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Bolivarian Republic of Venezuela Ministry of Popular Power for Education IUP “Santiago Mariño” Extention Merida

Teacher. Aracelis Torres

Vascular plants

Student: Yulexy Molina ID 20940660 Merida, 24-de enero del 2014


Introduction

Vascular plants, tracheophytes Also known as And Also higher plants, form a large group of plants are defined as Those That land plants have lignified tissues That the xylem for conducting water and minerals THROUGHOUT the plant. They also have a specialized non-lignified tissue (the phloem) to conduct products of photosynthesis. Vascular plants include the club mosses, horsetails, ferns, gymnosperms including conifers and flowering plants angiosperms. Scientific names for the group include Tracheophyta and Tracheobionta.


Characteristics Vascular plants are distinguished by two primary characteristics: 1. Vascular plants have vascular tissues which distribute resources through the plant. This feature allows vascular plants to evolve to a larger size than nonvascular plants, which lack these specialized conducting tissues and are therefore restricted to relatively small sizes. 2. In vascular plants, the principal generation phase is the sporophyte, which is usually diploid with two sets of chromosomes per cell. Only the germ cells and gametophytes are haploid. By contrast, the principal generation phase in non-vascular plants is the gametophyte, which is haploid with one set of chromosomes per cell. In these plants, only the spore stalk and capsule are diploid. One possible mechanism for the presumed switch from emphasis on the haploid generation to emphasis on the diploid generation is the greater efficiency in spore dispersal with more complex diploid structures. In other words, elaboration of the spore stalk enabled the production of more spores and the ability to release them higher and to broadcast them farther. Such developments may include more photosynthetic area for the spore-bearing structure, the ability to grow independent roots, woody structure for support, and more branching.


Transpiration The most abundant compound in all plants, as in all cellular organisms, is water which serves an important structural role and a vital role in plant metabolism. Transpiration is the main process of water movement within plant tissues. The basic minerals and nutrients a plant. Water is constantly transpired from the plant through its stomata to the atmosphere and replaced by soil water taken up by the roots. The movement of water out of the leaf stomata creates a transpiration pull or tension in the water column in the xylem vessels or tracheids. The pull is the result of water surface tension within the cell walls of the mesophyll cells, from the surfaces of which evaporation takes place when the stomata are open. Hydrogen bonds exist between water molecules, causing them to line up; as the molecules at the top of the plant evaporate, each pulls the next one up to replace it, which in turn pulls on the next one in line. The draw of water upwards may be entirely passive can be assisted by the movement of water into the roots via osmosis. Consequently, transpiration requires very little energy to be used by the plant. Transpiration assists the plant in absorbing nutrients from the soil as soluble salts.

Absorption Living root cells passively absorb water in the absence of transpiration pull via osmosis creating root pressure. It is possible for there to be no evapotranspiration and therefore no pull of water towards the shoots and leaves. This is usually due to high temperatures, high humidity, darkness or drought. Conduction Xylem and phloem tissues are involved in the conduction processes within plants. Sugars are conducted throughout the


plant in the phloem, water and other nutrients through the xylem. Conduction occurs from a source to a sink for each separate nutrient. Sugars are produced in the leaves (a source) by photosynthesis and transported to the roots (a sink) for use in cellular respiration or storage. Minerals are absorbed in the roots (a source) and transported to the shoots to allow cell division and growth.

Gymnosperms plants

The female cones produce eggs, which are contained in ovules. Female cones have a sticky resin that “catches� the pollen released by the male cone. When fertilized, the female cone enlarges and the scales separate. This separation allows the seeds to drop out of the cone and is dispersed by animals, such as chipmunks & squirrels.

Angiosperms Angiosperms are flowering plants that reproduce through seeds that are contained in fruit. The flower of a plant can contain male anatomy, female anatomy and sterile structures. A plant that contains both male and female anatomy is known as a perfect flower. A flower that only contains male or only female anatomy is called an imperfect flower.

Monocot Angiosperms


Angiosperms are broken into 2 groups: the monocots and the dicots. Monocots have 1 cotyledon, parallel veins, flower parts in multiples of 3 and scattered vascular bundles through out the stem. Examples of monocots are corn and grasses.

Dicot Angiosperms

Dicots contain 2 cotyledons, have a network vein pattern in their leaves, have flower parts in multiples of 4 or 5 and have their vascular bundles in a ring around the edge of the stem. Examples of dicots are roses and maple trees.


Anexos

Angiosperm and gymnosperms plants


Characteristic


Cycle of live

YULEXY MOLINA  

VASCULAR PLANTS

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