Micro
Questions & Answers
Pests
COMMONLY FOUND PLANT-ASSOCIATED AND THEIR FUNCTION
By Abha Gupta, MS Horticulture, Assistant
Fungi
Genus Trichoderma
The fungi of the genus Trichoderma live in soils that are rich in organic matter. These fungi are also capable of establishing symbiotic relationships with the roots of the plants that are found growing in those soils. The benefits provided by these mushrooms have been widely recognized in a multitude of studies. Among them, here are some of the most outstanding benefits. Plants, unlike animals, don’t have the ability to produce antibodies against those pathogens that penetrate their organism, however, they do produce other types of molecules,
especially proteins and phytoalexins (substances with fungicidal properties and bactericides), which help fight the attack of the pathogen. The plant begins to produce these substances when it detects that an insect is attacking it or when it suffers an injury from some chewing or herbivorous animal.
The fungi Trichoderma secrete a series of substances that cause the plant to produce these defense proteins and phytoalexins, though is not being harmed by any parasite.
Horticulturist
phytoalexins: antimicrobial compounds within a plant´s defense system which control for invading fungi and bacteria
Many phytopathogenic fungi produce enzymes that break down the cell walls of the plant they’re infecting. The products of decomposition of these cells serve as a sign to the plant that it’s being attacked. Trichoderma fungi produce enzymes, especially cellulases, which decompose organic matter (dead roots, remains of other crops, etc.). The products derived from this enzymatic degradation tend to be very similar to the ones that are provoked in the attack of a pathogen to the plant, so they serve as a signal to activate the production of resistance substances.
Figure 1: When triggered with potentially harmful stimuli, symbiotic fungi within the genus Trichoderma release enzymes that activate an immune response in the plant, which produces resistant substances such as proteins and phytoalexins.
Microparasitism is the capacity that these fungi have to parasitize and grow on other possible plant pathogens. For example, some species of Trichoderma may be useful to combat and prevent Rhizoctonia solani, a fungus causing damping off and rotting of the root, as well as Pythium and Phytopthera. This property has also resulted in foliar sprayings of Trichoderma to combat fungal diseases such as oidium or mold. This mycoparasitism also stimulates the plant’s defenses, as the products of pathogenic fungus degradation are very similar to those that serve as a warning
CANNARESEARCH
rhizosphere: the area surrounding plant roots in which biological, physical, and chemical interactions occur
signal to the plant. For example, chitosan is a component of the cell wall of fungi that is not found in plants, and which triggers the production of a number of defense substances. In addition, they favor growth in general of the host plant, improving as well the assimilation of certain nutrients.
Mycorrhizal fungi
Mycorrhizae are fungi that form a symbiotic relationship plant roots, where the plant provides sugars and the fungi provides water and nutrients to the plant. Some edible mushrooms function in this way, such as truffles which depend on partnerships with hazelnut and oak. Depending on the way in which mycorrhizae colonize the roots, they can be classified as endomycorrhiza and ectomycorrhizae. In the case of ectomycorrhizae, the mycelium only grows externally, surrounding the root superficially or, at most, penetrating intercellularly in shallow layers. Mycorrhizae are species specific. For example, ectomycorrhizae is symbiotic primarily with tree species such as pine, beech, oak, chestnut, poplar, and birch and endomycorrhizae is mutualistic with herbaceous plants such as tomato, strawberries, tobacco, and medicinal plants. (See Figure 2)
The secondary roots that grow from these colonized roots will grow already wrapped in the mycelium of the fungus. This external mycelium, which extends further than the root, serves the plant to take advantage of the nutrients
that are farther away from its root environment. In the case of endomycorrhizae, the colonization involves penetration into the inside of the cells. There are several types of endomycorrhizae, but the most important from the agricultural point of view are the vesicular arbuscular mycorrhizae (VAM). Some of these fungi are Glomus, Gigaspora, Acaulospora and Sclerocystis. In the symbiotic relationship the plant provides the fungus with sugars from the photo-assimilates, and the mycorrhiza provides nutrients that the plant alone could not or would not assimilate in a very small amount. Mycorrhizae are found naturally in outdoor settings and can help plants attain greater access to nutrients. In indoor production, where plants are watered and well-fertilized with readily available, mineral nutrients, mycorrhizae would not provide as much benefit. In any case, if choosing a mycorrhizal addition to your grow system, be sure to choose an endomycorrhizae or ectomycorrhizae species compatible with the specific plant you are growing.
Bacteria
Rhizobacteria
Rhizobacteria are a type of bacteria and are found in abundance in the rhizosphere. [¨rhizosphere¨ definition] They live specifically in plant roots or very nearby and can provide a symbiotic relationship with the plant. As rhizobacteria, also known as rhizobia, colonize roots of the plants, they fix nitrogen from gaseous form found in the atmosphere and turn
Figure 2: This mycorrhizae includes a fungus of the genus Amanita.
it into a solid form, held within the plant. Since nitrogen is one of the most demanded nutrient for plants, this quite a helpful benefit. These nitrogen-fixers collaborate specifically with leguminous plants like clover, bean, and pea varieties. When these leguminous plants are incorporated back into the soil and decompose, the nitrogen that they had fixed slowly breaks down and becomes plant-available to the next crop grown in that same soil. In essence, the rhizobacteria in concert with leguminous plants can provide a relatively cheap form of nitrogen, but – getting that nitrogen does require time.
How bacteria can make nitrogen for your system
This amazing nitrogen-fixing process happens specifically in root “nodules”, which are protrusions that grow off of roots, small and round in shape. These nodules are almost nonexistent in other plants. Root nodules were first discovered in 1888 by German scientist and later a Dutch researcher isolated the bacteria that were in said nodules. Thus began
the identification of rhizobacteria, belonging to the genus Rhizobium. Rhizobia work through the action of nitrogenous enzymes to turn gaseous atmospheric nitrogen into a fixed, solid form. This transformation takes place in the interior of the nodules, which are characterized by a dense pink liquid they contain. It is said that the relationship between Rhizobium and leguminous plants is endophytic, as the bacteria are developed inside the host plant. (See Figure 3)
Another endophytic bacteria that is also capable of nitrogen fixation is Azetobactor diazotrophicus, which develops in the interior of the sugar cane plant, distributing itself through the vascular system. Actinomycetes Frankia also forms nodules with nitrogen-fixing capacity in some trees and shrubs of the Casuarina genus. There are also other atmospheric nitrogen fixative bacteria that colonize the roots of plants which are not leguminous and which, unlike of the genus Rhizobium, are not developed in the inside of the host tissues but in the rhizosphere; such as bacteria from the genus, Azospirillum.
Figure 3: Rhizobacteria in the root nodule of leguminous plants convert atmospheric nitrogen into a form that is readily available for the plant.
endophytic: host associated microorganisms that live within the plant for at least some of their life
CANNARESEARCH
There are other atmospheric nitrogen-fixing bacteria genera that do not develop in the interior of the plants or in the rhizosphere and, therefore, are not considered rhizobacteria, such as those of the Azotobacter genus, which feed on decomposing organic matter in the soil. Be mindful that when growing in systems where mineral nitrogen is readily available, such bacteria will have a less vital role to play with nutrient cycling, but in long-term systems with crop rotations there is much greater room for application. Also, consider if the bacteria selected is plant specific – such as certain rhizobacteria with leguminous plants.
Additional benefits from bacteria
Improve nutrient availability
Like Trichoderma, there are rhizobacteria that are able to mobilize inorganic phosphorus and iron, which can be found in the soil as insoluble compounds unavailable to plants. Some of these bacteria are of the genera Bacillus, Pseudomonas, Amyloliquefaciens, Rhizobium and Erwinia.
Produce phytohormones for plant development
Many of these bacteria produce phytohormones such as natural auxins (indolacetic acid), giberelines or cytokinins, whose presence can improve processes of germination or rooting. A fungus that produces large quantities of auxins is Azospirillum sp.
Trigger
plant
defenses and
serve as disease control agents
These rhizobacteria don’t make the plant produce phytoalexins or resistance proteins, but enhance their production in case it is attacked by some phytopathogen. Others are helpful with stress tolerance, such as Bacillus and Amyloliquefaciens.
Bacteria can also be a suitable candidate for preventing root rot such as damping off and even to combat aerial fungi such as the Botrytis. Many rhizobacteria are producers of a type of antibiotics, some with fungicidal or antiviral properties. The main rhizobacteria that produce this type of antibiotics are those of the genus Pseudomona and Bacillus. Some antibiotics such as Mupirocin produced by P. fluorescens are widely used in medicine.
Genus Pseudomonas
Beneficial microbes compete with pathogens for nutrients or glucose and some have their own method of winning a competitive edge. For example, the fluorescent Pseudomonas bacteria can produce proteins that transform slightly soluble iron into iron chelate, which it can then absorb much more easily. This then deprives the Fusarium fungi of the iron it needs to grow, preventing it from developing
(Louis Bolk Institute). Competition for glucose can also cause microbiostasis which means that the spores of that pathogenic fungus germinate much more slowly due to a lack of energy from glucose.
Pseudomonas can also produce antibiotics, which can be another tactic to remove pathogens, while other microorganisms produce enzymes that attack the cell walls of competing species. Microbes that produce chitinolytic enzymes have the potential to act against pathogenic fungi. It has also been found that several microorganisms or closely related species can cooperate to fight a pathogen. They can simply overwhelm a pathogenic microorganism by multiplying more rapidly and thus depriving all the competition of resources and therefore any chance of survival.
An example is Fusarium, which can produce fusarium acid that affects the plant cells but can also suppress the production of antibiotics of Pseudomonas (this was discovered through research at Wageningen University in the Netherlands).
Review and decide for your own system
There are many different types of microbes available for growers and many can add benefit to your system. It is worth taking a pause to review the function of the microbes in consideration and how they will fit in your current grow system. Does your system need help with nutrient cycling, infection prevention, textural improvement? The more you evaluate before you make additions to your system, the better prepared you will be to enjoy your system’s full potential. •
ZUCCHINI THE HUMBLE
SOME PEOPLE SAY THAT IF A WAR BROKE OUT AND WE DIDN’T HAVE ENOUGH FOOD, THE HUMBLE ZUCCHINI COULD SAVE THE DAY. THEY’RE EASY AND THE ZUCCHINI IS ALSO A DEFINITE CONTENDER FOR THE SPEED RECORD OF THE VEGETABLE WORLD. ADD IN THEIR HEALTHY VIRTUES AND YOU’LL UNDERSTAND WHY THE COURGETTE COULD HELP US OUT IN OUR HOUR OF NEED.
By Marco Barneveld,
www.braindrain.nu
The zucchini: the racing car of the vegetable world. These plants are really fast growers. Sow some seeds today, and you could be harvesting your crop in about 45 to 55 days. These guys are prolific. In some places in the world they plant them in other people’s cars, or put them on their neighbor’s doorstep. They take sacks of them to work along with recipes for zucchini bread, zucchini casserole, and grilled zucchinis. Hell, they even use them as baseball bats because they have no idea how to use their bumper zucchini crops.
Figure 1: Zucchini blossoms are xan edible delicacy that can be baked, fried, steamed, used as fillers, or eaten raw.
Veggie-fruit
The scientific name for the zucchini is Cucurbita pepo, and it is a member of the same family as cucumbers and melons. The inhabitants of Central and South America have been eating zucchinis for several thousand years, but the zucchini that we know today is a variety of summer squash developed in Italy. In North America, these are known as zucchini, which comes from the Italian zucchino, meaning a small squash. The term squash comes from the Indian skutasquash meaning ‘green thing eaten green’. Christopher Columbus originally brought seeds to the Mediterranean region and Africa.
The French snubbed the zucchini for a long time until chefs learned to choose the smaller fruits, which are less bland and watery. The zucchini and its larger version, the marrow, is actually a fruit, although most people think of them as vegetables – something that many ‘veggie-fruits’ like the tomato, cucumber and squash share with the zucchini. The zucchini doesn’t really care. It’s too busy growing. Its popularity in Western cuisine is actually quite new. Less than thirty years ago, the zucchini, formerly often referred to as the green Italian squash, would hardly have been recognized. Today, it is not only widely recognized, but a particular favorite of home gardeners. Despite its prolific growing nature, its popularity is probably due to in large part to its versatility in the kitchen, as a vegetable as well as in breads and desserts.
Great health properties
• The zucchini is not bad for your health either. The zucchini is one of the very low calorie vegetables; it provides only 17 calories per 4oz. It contains no saturated fats or cholesterol. The skin is a good source of dietary fiber that helps reduce constipation and offers some protection against colon cancers.
• And to pull in some big words, Zucchinis have an antioxidant value of 180 Trolex Equivalents (TE) per 4oz. Which might be far below berries but nonetheless, the pods are one of the common vegetables included
Figure 2 . Growing zucchinis is easy. Zucchini seeds can be germinated indoors for a longer growing season or directly into the ground after the last frost. Sow the seeds in rows or hills, about 1 inch deep. Plant four to fiver per hill and after they have germinated, keep the best two to three courgette plants.
in weight reduction and cholesterol control programs recommended by dietitians.
• Furthermore, zucchinis are rich in flavonoid polyphenolic antioxidants such as carotenes, lutein, and zea-xanthin. These compounds help neutralize harmful oxygenderived free radicals and reactive oxygen species from the body, helping protect against aging and various disease processes.
• Zucchinis are a very good source of potassium, containing even more than bananas. Potassium is a heart-friendly electrolyte which helps reduce blood pressure and the heart rate by countering pressure effects of sodium.
• Fresh zucchini is rich in vitamin A and fresh pods are a good source of vitamin C. In addition, they contain moderate levels of B-complex group of vitamins like thiamin, pyridoxine, riboflavin and minerals like iron, manganese, phosphorus, and zinc.
Grow it yourself
Growing zucchinis is easy, perhaps too easy. Sow the seeds in rows or hills, about 1 inch deep. The row spacing depends on the variety you are planting. In hills, plant four to five per hill and after they have germinated, keep the best two to three zucchini plants. Water the first day and, if there is no rain, every two to three days until they germinate. Zucchini plants like well-drained soil, but will grow in most soils.
We chuckle at the idea of adding fertilizer to such a prolific grower, but some soils are poor in nutrients. If your soil is poor, or if last year’s crop was less than stellar, a side dressing of fertilizer and regular feedings of fertilizer will improve the health of the plant and the size of the harvest significantly.
Here’s another tip for you: an individual plant can produce fruit right up until the first autumn frost. But, most plants lose their vigor, or fall victim to insect and plant disease. They can also spread right across your garden, with only the growing tip producing new fruits. We recommend a second planting right around the first of July. The second crop will
be more vigorous and productive in the second half of the year than older plants.
Growing zucchinis is easy: sow the seeds in rows or hills, about 1 inch deep. Plant four to five per hill and after they have germinated, keep the best two to three courgette plants.
When to pick
Zucchinis are at their best during late spring and summer. The best size for picking zucchinis is 4 – 5 inches long and 1.5-2 inches in diameter. Avoid overly mature, larger fruits, or those with pitted skin or a flabby or spongy texture. Furthermore, avoid those with soft and wrinkled ends as they indicate old stock and dehydration.
Once picked, place the fruits in a plastic bag and store them inside the vegetable compartment of the refrigerator set with adequate moisture. They can be stored for up to 2-3 days around a week.
FAST RECIPE:
Zucchini blossoms are also an edible delicacy. In general, blossoms are picked during morning hours when they are fresh and soft.
To prepare, open up blossoms and inspect them carefully for insects. Pull off any calyces attached firmly at the base.
Preparing to cook
Wash the fruits thoroughly in cold, running water just before cooking. Sometimes the fruits may require light scrub at places where dirt is attached firmly. Trim the neck and bases. Peeling zucchinis is not recommended. Zucchini plants are not hardy. They are susceptible to frost in the spring and autumn. They are also very susceptible to insects and disease. Fortunately, these prolific producers manage to yield a bountiful crop even so. If you plan to grow them, make sure your plans include how to use the large quantity you will have. And make those plans elaborate. Like feeding your entire neighborhood! •
MARINATED ZUCCHINI yellow squash SALAD
You can create this colorful salad just as fast as your zucchinis grow. It’ll be ready in just 15 minutes and you’ll get an added kick of vitamin A from the fresh basil. Great tip: use the peeler lengthwise rather than horizontally to create long, beautiful green and yellow ribbons of squash.
You will need:
• 1/2 cup cider vinegar
• 4 teaspoons sugar
• 1/2 teaspoon salt, divided
• 3 zucchinis (about 1 1/2 pounds)
• 2 yellow squash (about 3/4 pound)
• 1 garlic clove, peeled
• 1/2 cup packed fresh basil leaves
• 1 tablespoon fresh lemon juice
• 1 tablespoon extra-virgin olive oil
• 11oz part-skim mozzarella cheese, cut into cubes
Preparation
ENJOY
Combine the vinegar, sugar, and 1/4 teaspoon salt until the sugar dissolves. Trim the ends of the zucchini and squash; cut into thin ribbons with a harp-shaped peeler. Add to the vinegar mixture. Cover and chill for 2 hours or overnight. Bring a small pan of water to the boil; add garlic. Remove with a slotted spoon after 1 minute. Rinse under cold water; set aside. Add the basil to the boiling water; immediately remove and rinse under cold water. Reserve 1 tablespoon of cooking liquid. Transfer garlic and basil to a food processor, and add lemon juice, olive oil, reserved water, and the remaining 1/4 teaspoon salt. Process until smooth. Drain the squash, and divide among 4 plates. Top with cubed mozzarella, and drizzle with basil oil. Now take your time to enjoy. Not everything needs to happen as fast as a zucchini.
am using the full CANNA Coco line. What
You can use an
QuestionsAnswers &
wilting slightly, even
My tomato plants (bush type) are I grow organic cucumbers in a small g
We receive a lot of questions about growing. Of course, our researchers are more than happy to answer them! Just go to the contact page on our website, www.cannagardening.com, to submit your question.
Question
I grow organic cucumbers in a small greenhouse. I use your BioCANNA BioFlores nutrient on a soil mix made of peat moss, sand, and kitchen-scrap compost from last year. The seeds start out fine, but as growth accelerates, the leaves turn a lighter green and gradually yellow from the bottom up. What should I do?
Answer
There are quite a few possibilities of what could be happening. Your plants probably need more nutrients (mainly nitrogen). Kitchen-scrap compost is usually better as a soil conditioner than as a source of nutrients. Also, you make no mention of liming your soil mix. If the pH is off, the mineralization of the compost can be very slow. Try using a complete and balanced organic potting mix to rule out potential potting mix imbalances, since the BioCANNA line is designed to work with a well-made potting mix with a good base. The soil temperature could be too low (over 64°F is best). Proper organic soil mix is a must, especially when growing cucumbers because these plants are heavy feeders. Hope this helps!
Question
I am using the full CANNA Coco line. What is the appropriate amount of time to feed plain water before harvest? I have heard anywhere from no flush is required to 2 full weeks of feeding just plain pH adjusted water to leach the medium and the plant of nutrients so that the final product will be better. I am at week 7 of a 9 week plant.
Answer
Question
My tomato plants (bush type) are wilting slightly, even though the soil is not dry. This only happens once they have reached full size. Sometimes, I even lose a plant or two. I have also noticed some leaves burn from the edges inwards and most of the fruits do not mature properly. Can you help me? I am at a loss to understand this.
Answer
You could be consistently over-fertilizing your plants. This would definitely result in rapid and luscious growth. But,once the soil salinity exceeds a certain level (at full height) the high salts in the soil will actually begin to draw back the water from inside the plant (this is called reverse osmosis). Do an EC test on your soil to confirm this and change your fertilization technique accordingly. To save your existing plants, water with plain water or with an Epsom salt solution of around 0.5 EC and water until the runoff has the same EC as the water you are applying. The Epsom salt solution is more effective at removing nutrients from the soil (the magnesium kicks off nutrient elements adhering to cation exchange sites) so that your soil is left ready to be reset with a properly balanced nutrient solution. So, after you apply either plain water or your Epsom salt solution, then apply your nutrient solution till you get good runoff. Good luck and lay off the sauce!
Final flushing is done to force the plant into using up all its nutrient reserves that are moving through the vascular tissues and cells. This would imply that the correct amount of time to do so is to the point problems, usually yellowing, begin to occur. This can and will vary based on environmental conditions, level of fertility, the medium, and good old genetics. Typically, this takes 5-7 days, but it can be shorter in hydro systems and longer in organic mediums and for certain varieties, up to 14 days in some cases. This is a grower choice based on conditions, crop, and so forth.
I grow organic cucumbers
in 5 gallon containers. The vines are tied to
One cause comes to mind. Adding guano and vermi-compost into
the soil mix can introduce a high level of nitrogen in the form of amonium
Question
Would I need any other additives if I elect to use reverse osmosis water on my next grow cycle? I am currently using well water and everything is growing well. I am not sure if there are any benefits for me to change to RO water on the next grow. Any advice would be appreciated.
Answer
We have a saying here, “if it ain’t broke, don’t fix it.” The main points to consider with your well water is evaluating if it contains any elements at potentially toxic levels (particularly chlorine and sodium) and if it is considered hard or soft water. If you are growing on coco medium, moderately hard to hard water is ideal and if you have soft water you would want to amend it with calmag. If using our Substra line, we have a hard water and soft water option – so you can choose what’s best for you. Our Aqua line is optimal with soft water. And lastly our Terra or BioCANNA line is more forgiving of a range of water hardness, since the assumption is that you are growing on a welllimed potting mix. That said, without knowing what you are growing on – if you’re plants are looking well then there wouldn’t be a reason to RO your water (rendering it soft water).
Question
I grow organic cucumbers in 5 gallon containers. The vines are tied to a vertical trellis. I use a locally reputed organic soil mix and amend it with vermi-compost and good quality guano. The plants grow extremely fast and lush. The problem is that they are also host to some mildew fungi, probably powdery mildew. Once the leaves are affected, the fruits don’t develop normally and some develop rot. I grow a large variety of organic plants in that area and never have issues with that disease. I do not spray anything on the foliage. Any ideas?
Answer
Question
A friend of mine and I have been arguing about oscillating fans. He tends to like more air flow from many units. In my experience, too much horizontal air flow damages a lot of flowers and leaves and seems to restrict growth. Help us figure out who is right, please!
Answer
One cause comes to mind. Adding guano and vermi-compost into the soil mix can introduce a high level of nitrogen in the form of ammonium. Ammonium will definitely boost growth and green up a plant. It also reduces the plant´s capacity to withstand fungal and insect attacks. High ammonium nutrition can also interfere with proper flowering and fruit formation. Guano is reputably very rich in rapidly released ammonium nitrogen. Try cutting the concentration down or taking that ingredient out of the soil mix. Ensuring that the foliage is dry going into night, avoiding overhead irrigation, and looking at other varieties may also help.
You may both be right. I suspect your friend grows with higher relative humidity values than you do. At higher moisture levels, the plants prefer more horizontal air movement. It prevents the air immediately surrounding the leaves from becoming saturated with water vapor and it promotes transpiration. When the growing climate is dryer (below 50-55%), it is wiser to reduce the air flow as it can lead to desiccation. This puts the plants under stress – they will not transpire correctly and may suffer. Another trick is to set your oscillation fans on a cycle timer to have them run for a minute and stay off for five minutes, so that the foliage is not dealing with the wind the whole time. height) the high salts in the soil will actually begin to draw back the water from inside the plant (this is called reverse osmosis). Do an EC test on your soil to confirm this and change your fertilization technique accordingly. To save your existing plants, water with plain water or with an Epsom salt solution of around 0.5 EC and water until the runoff has the same EC as the water you are applying. The Epsom salt solution is more effective at removing nutrients from the soil (the magnesium kicks off nutrient elements adhering to cation exchange sites) so that your soil is left ready to be reset with a properly balanced nutrient solution. So, after you apply either plain water or your Epsom salt solution, then apply your nutrient solution till you get good runoff. Good luck and lay off the sauce!
Question
I grow in an ebb and flow garden and am happy with the results. I have recently noticed that a slimy substance is covering the walls of the reservoir. It is translucent and only appears after four days from the main tank change. Nothing a good cleaning agent can’t get rid of! Still wonder if it can affect my plants?
Answer
This slimy substance is usually a byproduct of a bacteria living in your reservoir. If your plants are thriving and you regularly sanitize the equipment, it most likely will never affect your crop. If you want to reduce the onset of this situation, here are a few tips:
-Reduce or eliminate air injection stones and apparatus in the tank. The added oxygenation promotes bacterial development and skews the pH.
-Reduce or eliminate protein based organic additives such as fish emulsion or blood meal.
-Discontinue use of compost teas or microbial inoculants.
-Keep water temperature under 75°F.
SEQUOIAS
• Sequiadendron giganteum also called the giant sequoia, holds the record for largest tree found in the world at 275 feet tall with a 36 foot diameter base. This tree is named General Sherman and is also the largest living organism by volume on the planet at 2.7 million pounds.
DID YOU KNOW THAT...?
• Alana Chin at the University of California discovered that coastal redwoods drink water through their leaves. These sequoia grow two different kinds of leafy shoots. These are traditional needles that aid in photosynthesis and specialized shoots that absorb water from the air at four times the rate.
• Sequoia sempervirens, or coastal redwood, holds the record for tallest tree found in the world at 379.1 feet tall.
• Giant sequoias can live up to 3,000 years old, making them the third longest lived tree species.
• Sequoia tree bark can grow up to three feet thick.
• A tall coastal redwood absorbs up to 13 gallons of water in the hour after it gets wet.
• Sequoias are extremely hardy due to the high concentration of tannic acids in their bark which protect against fungal rot and wood boring insects.
• Giant sequoias produce seeds in cones once in their long lifetimes. These seeds are activated and released from the cone during forest fires.
HAPPENING What ,s
You can’t squeeze blood from a stone, but wringing water from the desert sky is now possible thanks to a new sponge-like device that uses sunlight to suck water vapor from the air, even in scorching hot and dry biomes. Text: Marco Barneveld
FROM HAR VESTING WATER
This gorgeous blue planet we live on is called blue for a reason. That reason is water. The only tiny problem with that water is that it is not divided equally. The lack of water in deserts makes it a unique growing environment and native desert plants have evolved to adapt to dry, rugged conditions. Deserts cover about one-fifth of the Earth’s land surface and while it may seem that they are deplete of water, the funny thing is that there is always, at least, some water in the air.
At any given time, about 13 trillion liters of water are floating in the air. This equals 10% of all the freshwater in the lakes and rivers on Earth. Over time, scientists have come up with ways to catch a few drops, like using fine nets to pull water out of fog banks or power-hungry dehumidifiers to pull it out of the air.
Fog and dew
Fog and dew harvesting are two ways to harvest atmospheric water now, but both have many problems. Fog harvesting only works when the relative humidity is 100% and it is only used in a few coastal deserts at the moment. Dew harvesting, on the other hand, requires a lot of energy to provide cold surfaces for water to condense on and it still needs humidity of at least 50%, depending on the temperature of the air.
So, both of these methods need very humid air or a lot of electricity to be helpful on a large scale. But, a new spongelike device that uses sunlight to pull water out of the air, even when it’s dry, makes it possible to get water from the air, even in the desert.
Jus t sunlight
The new system can work with as little as 20% humidity and doesn’t need any energy other than sunlight or any other source of low-grade heat. That means that soon, homes in the driest parts of the world could have a solar-powered device that can give them all the water they need, helping billions of people.
Professor Evelyn Wang, head of MIT’s Department of Mechanical Engineering and her team have made a significant improvement to a design initially developed in 2017 that can use heat from the sun or another source to pull drinkable water directly from the air, even in dry places in remote regions with limited access to water and electricity.
Adsorbent material
The earlier device harnesses a temperature difference within the device to allow an adsorbent material, which collects
liquid on its surface, to draw in moisture from the air at night and release it the next day.
But that device needed expensive metal-organic frameworks (MOFs), which are limited in supply, and the amount of water it could produce was not enough to make it worthwhile. Now, by adding a second stage of desorption and condensation and using an easily accessible adsorbent material, the researchers say they have greatly improved the device’s output, making it much more likely that it could be used widely.
Zeolite
Instead of MOFs, the new design uses an adsorbent called zeolite. The material is easy to find, stable, and has the right adsorbent properties to make a good water-making system using only regular day-night temperature changes and heating from the sun. Drops of water from the system can be collected in a tank using a funnel.
The system’s overall productivity is about 0.8 liter per square meter daily. Double the amount of water compared to the first version. The exact rates depend on temperature changes, the amount of sunlight in the area, the level of humidity, and the adsorbent material.
Can we cool the planet?
Now that the system has been shown to work, scientists can look for even better adsorbent materials, which could increase the water harvesting rates even more.
The current rate of about 0.8 liters of water per square meter per day may be enough for some uses. It will at least stop you from dying from thirst, but it’s not enough to grow crops.
But if the water harvesting rates can be increased through better and smarter adsorbent materials, it could even work for some crops. According to professor Wang, there are already adsorbers being made that can adsorb about five times more water than this zeolite. This could lead to a similar increase in water output. And, what if we use more than one thermal cycle per day and get the heat from something other than the sun?
Will we be able to harvest atmospheric water in such an amount that our deserts will turn green and fertile? Will we be able to color the planet green in that one-fifth of the planet, which is desert? And if we do, could we cool down the world? The future will tell. •
Pests & DISEASES
After the discovery of viruses in the last years of the 19th century, biologists and philosophers have debated for almost 100 years about the latter being the smallest life form known to man.For many years viruses were considered the paradigm of DNA/RNA programmed for its own survival. Raw and effective, a virus ¨carries¨ and replicates a very small fragment of genetic material, necessary to encode the proteins (often enzymes) needed to subdue the host cellular metabolism, infect nearby cells, and replicate the virus, destroying the host cell.
Theodor O. Diener (US Department of Agriculture, Beltsville, Maryland, U.S) discovered the first viroid in 1971 through first contact with the infectious agent of potato spindle tuber disease.VHe showed that the agent is a free RNA of 359 nucleotides, too small to contain the genetic information necessary for self-replication nor capable to synthesize a shell.
“Viroids, the smallest known infectious agents belong to the new order of sub-viral agents”
Andrea Properzi, QM at Fundacion CANNA, Editor: Abha Gupta, MS Horticulture
Figure 1: HLVd consists of a single stranded polymer of 256 nucleotides that assume a rod-like structure. HLVd is characterized by a subtle infection of hops, as the name suggests.
Viruses are cellular hackers
After the injection of their genetic material, viruses take over the cellular machine, start synthesizing their own enzymes and proteins and induce both self replication and infection of nearby cells. These ancestral hackers are well protected by a capsid, a protein shell. Capsids give viruses their observable shape, vector viruses during their migration in the organisms, and act as sensors for specific cellular membranes identified as targets.
Viroids are shapeshifters.
Characterized and shaped just by their genetic materials (RNA), viroids are naked structures interacting with the environment. The nature, orientation and strength of the interaction with nearby compounds are able to modify the
geometries of the viroid that is able to adapt to great number of chemical environments.
Hop Latent Viroid disease (HLVd) HLVd symptoms
A plant with HLVd shows a set of strange symptoms: growth stunting, brittle stems, poor flowering and expression of secondary structures and metabolites, malformation and/ or chlorosis of the leaves; without an evident cause. Plants can also be latent, asymptomatic carriers. The latency period between the infection of the plant and the appearance of the first symptoms can not be attributed to a single determining factor and may vary greatly between different chemo-types. (see Figure 1)
Data harvested from different studies seems to indicate that young individuals are more efficient in recognizing/fighting foreign RNA fragments as viroids, generating the delay that we rationalize as latency.
HLVd alters the growth/defense ratio of the infected plants meaning a generalized delay in growth, which effects nutrient uptake. The second and increasingly preoccupying effect is on primary and secondary structures like flowers/
fruits and hairs/spikes, leading to potential yield losses between 30-80%.
(See Figure 2)
Transmission and Precautions
The recovery of clean genetic material from contaminated samples is harder than it may sound: HLVd is capable of surviving for long periods of time outside the comforts of
Figure 2: HLVd alters the growth/defense ratio of the infected plants meaning a generalized delay in growth, which effects nutrient uptake. The second and increasingly preoccupying effect is on primary and secondary structures like flowers/fruits and hairs/spikes, leading to potential yield losses between 30-80%.
living cells and dead tissues have been proven to spread the disease.
The use of sterile indoor environments, single-use gloves and tools and a proper biological isolation of contaminated plants, has been recommended. Ten percent bleach solution or Bunsen burner/flame sterilization are conservative ways to prevent/avoid contagion via reusable tools limiting the expenses relative to one-use materials. HLVd spread through seed is less common but cannot be excluded yet. Seeds should be considered as small ¨vaults¨ for DNA structures and are among the harshest environments for foreign genetic material; preventing the accumulation of the pathogen. The outside of the seeds could still carry debris and other fragments that may act as viroid vectors; a mindful treatment (washing) is advised to further reduce the risk. Studies on HLVd on hops seem to exclude contagion via insects. As for many other pathogens the best way to ensure a rapid response to HLVd is a solid analytical program.
Reverse transcription PCR (RNA Polymerase chain reaction) testing involves amplifying RNA sequences in the sample and after few passages, identifies known fragments (viroid sequences and fragments) with high precision, allowing for an early diagnosis. Testing through third party labs can range from $25-50/test. Larger growers may opt to build their own testing facility, which costs well into the thousands of dollars. Multiple sample submissions are needed per plant in order to confidently determine that the plant is viroid-free, due to its latent nature. To effectively diagnose a disease free plant, some labs recommend a minimum of 3-4 tests per plant,
each test taken 1-2 weeks apart. Growers would want to be especially careful with stock plants.
If a facility is tested positive to HLVd, the selected genetics may still be saved, labs/companies have developed their own patented technique to fight viroid accumulation in specific tissues.
Heat and/or cold treatments are generally used on meristem or nodal tissues culture in order to clean the sample. Cleaned plant tissue cells are than grown on specialized growth media and propagated to create disease-free rooted shoots referred to as a “plantlet” (aka micropropagation). The biggest drawback for this procedure is the price that may reach the thousands of dollars.
Conclusions
Just as we all experienced over the last few years, it can be challenging to manage a virus and HLVd brings its own stubbornness. However, with persistence and collective effort, the virus can be prevented and managed. d – the cultivar can be saved using lab techniques. Meristematic or nodal tissue sample can be treated using a heat or cold therapy (the exact treatment is protected by each lab) until it is rendered disease-free. This material can then be used to generate new, clean plants using tissue culture technology.
It can be challenging to ensure that your plant production remains completely free from diseases, but every effort made towards this will be worth saving future headache and lost value. Good luck while protecting your plants and as always, feel free to reach out as questions come up.
Bibliography
Gergerich, R.C., and V. V. Dolja. Introduction to Plant Viruses, the Invisible Foe. The Plant Health Instructor. 2006 DOI: 10.1094/PHI-I-2006-0414-01
Patzak, J.; Henychová, A.;Krofta, K.; Svoboda, P.; Malíˇrová, I. The Influence of Hop Latent Viroid (HLVd) Infection on Gene Expression and Secondary Metabolite Contents in Hop (Humulus lupulus L.) Glandular Trichomes. Plants 2021, 10, 2297. https://doi.org/10.3390/plants10112297
Holger Puchta, Karla Ramm and Heinz L.Sanger. The molecular structure of hop latent viroid (HLVd), a new viroid occurring worldwide in hops; Accession no. X07397 Max-Planck-Institut fuir Biochemie, April 18, 1988
Marina Barba, Zhibo Zhang. Viroid Elimination by Thermo-therapy, Cold Therapy, Tissue Culture, In Vitro Micrografting, or Cryotherapy:, in Viroids and Satellites, 2017
MICROBES WILL FIND THEIR WAY INTO ANY GROW SYSTEM, WHETHER YOU INVITED THEM IN OR THEY SHOWED UP UNANNOUNCED. IF YOU WANT TO ENCOURAGE BENEFICIAL MICROBES, YOU NEED TO FOSTER A HEALTHY ENVIRONMENT WHERE THEY CAN PROSPER. AND AS FOR KNOWING WHO TO INVITE? THIS DEPENDS ON THE SYSTEM IN WHICH YOU ARE GROWING. SOIL, COCO, INERT HYDROPONICS, AND AEROPONICS EACH HAVE SPECIFIC PHYSICAL AND CHEMICAL PROPERTIES THAT WILL IMPACT THE DECISION ON WHICH MICROBES ARE THE BEST FIT. BEFORE REVIEWING EACH SYSTEM, LET’S START WITH REVIEWING IDEAL CONDITIONS FOR YOUR PREFERRED MICROBIAL ECOSYSTEM.
By Abha Gupta, MS Horticulture, Assistant Horticulturist
Ideal conditions for beneficial microbes
Moisture and aeration
In order for microbes to thrive within a substrate, they need ideal environmental conditions. Just like people, microbes need food, shelter, and water – which translates for them as moisture content, aeration, proper pH and EC content, and a food source. For the type of microbial life that growers typically want to see thrive in their terrestrial ecosystem, the substrate needs to have the right amount of moisture – not too wet and not too dry. If the substrate is too wet, the majority of pore spaces are filled with water, leaving little room for oxygen. Healthy microbes need oxygen in their habitat, also known as aerobic conditions. Other microbes will propagate in anaerobic conditions, meaning there is little to no oxygen and generally a high water content instead. However, anaerobic
Figure 1: Microorganisms can significantly affect the development of plants growing in the substrate, both positively and negatively. Many factors are important for microorganisms, such as the type of growing medium, moisture levels, amount of oxygen, organic matter, pH, and salinity.for beneficial
microbes are not typically the kind of microbes growers are striving for in their grow environment. In addition, low oxygen environments can slow nutrient release within the root zone, as both microbes need air to break down nutrients into plant available forms and the nutrients themselves require oxygen to undergo chemical processes that render their elements as
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plant available. Plants grown in a substrate with very little oxygen will usually be weaker and pathogenic anaerobic microorganisms tend to benefit from that.
Sources of energy
Now that we’ve established that the proper moisture and oxygen content must be available to microbes, let’s review their demand for food. Microbes feed off of organic matter, which is broken down carbon material. This includes decaying roots, stems, or other plant parts and organic materials found in potting mixes and substrates. Substances that are exuded from the root system like sugars, amino acids or phenols can either attract or repel microorganisms. Plants can be strategic
Figure 2: Rhizopus is a genus of common saprophytic fungi on plants that helps with decomposition. You´re likely familiar with Rhizopus as it´s responsible for mold on rotting fruit and bread.
by exuding substances that attract beneficial organisms, establishing a symbiosis with a particular microorganism. An example of this is the presence of symbiotic bacteria in the root nodules of leguminous plants such as peas or beans, which convert atmospheric nitrogen into a form that can be absorbed and used by the plant.
“Humic substances: the remains of ecomposed plants and animals that make up organic matter in soil and water”
saprophytic: to obtain nutrition from decaying organic matter
As microbes chow through organic material, they help to create better aeration as the material they ate is left as an empty space within the substrate. Microbes leave behind humic substances which serve as a type of glue to hold these pore spaces structurally. While this helps with soil texture, over time substrates become compressed, which needs to be considered reusing substrate and amending it so that ideal texture is regained. In addition to carbon based materials, microbes are ready to feed off of nutritive elements made available to them as well. This can be helpful when microbes decompose a carbonbound nutritive element and render it to a form that a plant can then use for growth. Similarly, when microbes break down old, decaying plant parts, they can help prevent fungal diseases as they encourage nutrient recycling. On the down side, microbes are just like humans in that they typically are not going to work harder than they need to. When we fertilize plants, microbes will consume some of the fertilizer load applied, as it is readily available, as compared to having to break down nutrients from a complex form. Work smarter not harder, right?
Environmental pH
Another environmental condition to consider is the pH. This is obvious for plant production and also very important for microbes. Most microorganisms prefer a pH 5.5 and 5.8. Extreme pH levels, as well as pH fluctuations can disturb the development of microflora. The salinity or EC level in the substrate will also affect the growth of microorganisms and in particular, the type and composition of the salts in the growing medium also has an impact. This is especially true of salts such as potassium chloride or sodium chloride that can change the rhizosphere of plants and thereafter, the microbial community as well.
Microbes suited for each grow system
Soil-based
It can be fairly straightforward to think of covering the basic living requirements of microbes, but this goes further when applied to grow systems where we can evaluate what the benefits vs trade offs are for adding microbes. Starting with soil based systems, there are clear compatibilities with microbial additions. Soils tend to contain organic matter, which provides a food source for microbes. Microorganisms that have a high saprophytic capability (meaning they live off dead organic matter) will do better in a substrate containing organic material such as peat or reused substrate.
Dead leaves or other plant parts lying on the surface of the substrate will do just as well. In addition, soils are a dynamic habitat where a microbial community will almost certainly develop on its own. However, one needs to be conscientious of promoting the type of microbes that truly are beneficial. Part of this is achieved by maintaining proper moisture and aeration. Microbes behave in sort of a build it and they will come kind of manner, so it’s possible that by creating welcome conditions you are creating the start for a healthy microbial ecosystem. Another logical approach is to inoculate a soil based system with an ideal blend of microbes, to begin
CANNARESEARCH
with, ensuring that an appropriate balance is being created. Growers may select microbes to target nutrient recycling, disease prevention, and enhance substrate texture. (To find out more about specific microbes and their function, see the article, “An overview of commonly found plant associated microorganisms and their function,” found in this magazine.)
In a long term, living soil type of system, microbes for nutrient recycling are helpful as growers build up a base of organically bound nutrients, such as compost, manure, and cover crop plant remains. These can also be found as parts of the living plants themselves sloughs off into the root zone or, depending on how the soil is managed, old roots are broken up and incorporated back into the soil. Some microorganisms can actually produce enzymes that can decompose accumulated salts. As the soil is used over time, the texture will become compressed and less aerated, which is where microbes can be helpful. Some microbes can help to improve soil texture and will be a welcome fit in many soil based systems.
Coco
Coco based systems are unique in their ability to maintain quality texture for a longer time compared to a typical soils based system. Also, in a purely coco-based system, organic nutrients are
not applied but instead readily available mineral nutrients are applied. The implications of these features of coco means that it may not be as beneficial to apply microbes that target textural and nutrient recycling goals. However, microbes would still be helpful in decomposing old plant material and rendering it into plant available nutrients. Lastly, coco systems are still vulnerable to infections and microbes can be used to prevent or treat such inflictions.
Rockwool, clay, sand
When growing in inert substrates, like rockwool, clay pebbles, or sand, microbes again can be helpful for disease prevention and treatment and for decomposing old roots into useful nutrients. However, these inert systems are generally fertilized with readily available, mineral nutrients, so a microbe is not left with a big role to play with nutrient breakdown. Likewise, when growing in an aeroponic system, microbes are not necessary for nutrient turnover. And lastly, when growing in deep water culture, the constant moisture and lack of sufficient aeration may prevent microbes from thriving and being truly effective.
Considerations for your microbial additions
While adding microbes in a grow system has many potential benefits, be sure to have a full understanding of your system components and the goal of the microbes you are adding. Take caution with the quantity of microbes that are being added, as well. More does not always mean more and overloading a system with microbes may contribute to the microbes consuming some of the nutrients you intended to go towards your plants’ development and this can even lead to a deficiency. Avoid unwanted mistakes by gearing yourself with knowledge. After all, knowing is growing! Take the time to learn your system, be deliberate about your inputs, adjust as needed, and enjoy your grow! •
Grower,s
KNOWING ABOUT PLANT PHYSIOLOGY IS YOUR QUICKEST AND SAFEST ROUTE TO EASY, PLENTIFUL YIELDS!
If your goal is to harvest plentiful yields every time, find out exactly what your crop needs, and provide it. On the other hand, if a few failed crops, lower than expected quality, or other disappointment are not going to push you into bankruptcy, go ahead and learn by trial and error. Grow that cactus in sitting water and see how it goes.
As you probably know, water moves up from the roots through the stems and then evaporates out through the leaves, carrying along nutrients and other things that the plant needs. Each type of plant has evolved in different versions and each
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¨As a first time microgreens grower this Canna brand Coco brick was a life saver. So easy to use and virtually mess free due to the fact that it comes in its own mixing bag.
I used no other nutrients this round, just the Coco and r.o. water and they came out fantastic. Will definitely be using this product for every run.¨ -Jennifer
CANNAtalk wouldn’t be complete without a good old Sudoku puzzle. Sit down, relax and train your brain for a moment. ! Are you new to this kind of puzzle? Here’s what to do: each row, column and 3x3 grid must contain all the numbers between one and nine, once only.
STUDY FINDS PLANTS CAN TALK, BUT WHO IS LISTENING?
Over the years, more studies have proven that plants have a secret language previously unknown made up of visual, chemical, and tactile cues. Sound is an important form of communication for many organisms so why would plants be any different? This curious pondering led to a recent breakthrough by research professors at the University of Tel Aviv in Israel who discovered that plants actually produce sound waves beyond what the human ear can hear.
To test whether plants create sound, researchers built recording systems in isolated acoustic boxes with microphones that could detect ultrasonic sounds ranging from 20-250kHz. For reference, the maximum frequency that a human adult can detect is approximately 16kHz. They used healthy tomato and tobacco plants as a control group to compare against the same species exposed to different individual stressors; drought and injuries (cuts).
Surprisingly, they were able to record intermittent, hollow, popping sounds believed to come from cavitation, or the formation of bubbles. Researchers suggest that the sounds
Facts
By Margaux Cline
occur when an air bubble in the plant´s cytoplasm pops due to pressure. The healthy plants hardly made these sounds but the stressed plants emitted 30-50 per hour.
To test this further, the scientists moved the experiment into a greenhouse and created a machine learning models to categorize the different sounds picked up on the microphones. In a groundbreaking discovery for bioacoustics, the computer algorithm was able to differentiate between the plants based on whether they were unstressed, thirsty, or cut. Imagine recording your garden´s sounds to determine which plants are stressed!
Just because plants are making these sounds in specific patterns, doesn´t mean that they are communicating or that anything is aware of these cues. However, we know that many insects, mammals, plants, and microbes respond to sound. Are plants using these noises to communicate? Are these sounds detectable to other organisms? More research is needed to determine if plants use sound to interact with their environment and if anything can understand them.
Khait, Itzhak, et al. “Sounds Emitted by Plants under Stress Are Airborne and Informative.” Cell, vol. 186, no. 7, Mar. 2023, pp. 1328-1336.e10, https://doi.org/10.1016/j.cell.2023.03.009.
NEW MICROBES COULD BE THE FUTURE OF RECYCLING
sing microbes to process our biodegradable plastic waste isn´t a novel finding. The issue has been that although microbes were proven to degrade plastics in the past, scientists have only ever discovered species that can do so at higher temperatures (86 degrees F) meaning the process requires a heat source. These systems are costly and not carbon neutral which have challenged researchers to find microbes that can break down plastics at lower temperatures.
Thanks to scientists at the Swiss Federal Institute of Technology, two previously unknown fungal species have been discovered in the Swiss Alps and Greenland that can degrade plastics at lower temperatures. These species produce the digestive enzymes to break down plastics at 59 degrees F, bringing us closer to carbon neutrality. Now, researchers can look into what temperature is optimal for this degradation and further their understanding of the enzymes responsible. With over 367 megatons of global plastic production that harm aquatic, terrestrial and soil life, these fungal microorganisms could be the superheroes we need to heal the planet!
Rüthi, Joel, et al. “Discovery of Plastic-Degrading Microbial Strains Isolated from the Alpine and Arctic Terrestrial Plastisphere.” Frontiers in Microbiology, vol. 14, 2023, https://doi.org/10.3389/fmicb.2023.1178474.
CANNA Research Grow it Yourself Questions & Answers
Factographic What’s Happening? Pests & Diseases
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Editors: Abha Gupta and Margaux Cline
Email: editor@cannatalk.com
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Contributors issue 41: Marco Barneveld, Margaux Cline, Abha Gupta, David Hill, Andres O´Hara, Andrea Properzi, David Rosenberg and Mirjam Smit.
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