Using Ethylene Inhibitor and Polyamine…

Using Ethylene Inhibitor and Polyamine to Extend Turf-type Tall Fescue Sod Shelf Life

By Xunzhong Zhang, Ph.D., J. Michael Goatley, Ph.D. and Jon Dickerson School of Plant and Environmental Sciences Virginia Tech, Blacksburg, VA

One of the major concerns sod growers have is sod quality decline after harvest and during transportation. Heat accumulation due to respiration and ethylene production during sod storage cause heat injury of sod and accelerate leaf senescence, especially during summer months. A standard practice in the floriculture industry for lengthening the life of cut flowers and potted plants is postharvest treatment with the ethylene inhibitor 1-MCP; EthylBloc). However, to our knowledge, no study has been conducted to investigate the effects of 1-MCP and other compounds with ethylene inhibiting function on ethylene production, heat injury and shelf life of tall fescue sod. This study was to investigate effects of three ethylene inhibitors on extending shelf life of turf-type tall fescue sod.

PHOTO 1. The harvest of the treated sod occurred on July 2, 2020.

The trial was conducted at Virginia Tech Turfgrass Research Center during summer 2020. There were eight treatments (control, aminoethoxyvinylglycine (AVG), spermidine (SPE), EthylBloc alone or in all possible combinations). A randomized block design was used with four replications. Foliar application of AVG (25 µM) and SPE (0.25 mM) alone or in combination to turf took place on June 30, 2020, 48 hours before sod harvest. Immediately prior to harvest, all individual and combination treatments containing EthylBloc were initiated by placing two bags (wetted) of EthylBloc sachet with active ingredient being the ethylene inhibitor 1-methycyclo-propene (1-MCP) (provided by Oasis Grower Solutions) in each piece of sod. The treated sod was harvested (photo 1) and placed under rainout shelter for 72 hrs and temperature and ethylene production inside each sod roll were monitored from 0 to 72 hrs (photo 2), and then the sod was transplanted into the prepared field plots for recovery test (photo 3). Turf visual quality was rated weekly on a visual scale of 1 to 9 with 9 indicating the best quality. Photochemical efficiency was measured with a chlorophyll fluorometer weekly for a period of six weeks. At the end of the trial, the root strength was measured. The results showed that application of ethylene inhibitors reduced ethylene production in the sod roll during 72 h period from July 2 through July 5.

PHOTO 2. Temperature sensors and tubing for ethylene sample collection were placed in the center of sod roll.

PHOTO 3. Sod was transplanted on July 6, 2020.

At the end of sod storage (July 5), all ethylene inhibitor treatments except for SPE reduced ethylene concentration. The transplanted sod experienced so called “post-transplant shock” and a reduction in turf quality in the first week after transplanting, but gradually recovered in the following weeks. We found all inhibitor treatments except for AVG, and AVG+SPE+EthylBloc improved turf quality rating when compared to the control as measured on July 20 (two weeks after transplanting). On August 5, all ethylene inhibitor treatments had higher turf quality rating than the control. The ethylene inhibitor treatments consistently improved photochemical efficiency. Application of AVG, EthylBloc, and AVG+SPE increased root strength of transplanted sod as measured on August 10. Th preliminary results of this study suggest the ethylene inhibitors could be used to extend shelf life of tall fescue sod and further study is warranted to investigate the mode of action and confirm the results.

We acknowledge the Virginia Agricultural Council, Turfgrass Producer’s International, and the Virginia Agriculture Experiment Station for their support of this research.