Pre-harvest application of proprietary elicitor delays fruit senescence

Abstract

The proprietary elicitor, YEA!, is an organic patented material derived from exoskeletons of crustaceans. YEA! appears to be responsible for actually reducing ethylene biosynthesis. This was tested using triple response assays on etiolated Arabidopsis thaliana seedlings, which is conducted using seeds germinated in the dark. Normally elongated hypocotyls (stems) are severely reduced in length by low concentrations of ethylene. When the seeds were germinated on agar medium containing 0.1 mg/mL YEA!, the results were the same as controls and indicated ethylene was not produced by the seedlings. Ethylene is a plant hormone that is associated with senescence. Sorenson compared YEA! with a water control by spraying the leaves once and two applications to the soil around orange trees several weeks preceding harvest. Fruit from treated trees was picked later than from untreated control trees, as abscission was delayed. In addition, post-harvest gassing procedure with 10 ppm ethylene gas for 4 days at 20°C was more severe than normally used on picked citrus to induce degreening. Data in Fig. 1 represent citrus treated with YEA! in comparison with fruit picked from trees treated in an identical manner, except with water. Application of YEA! results in the delay of fruit sensecence, and gassed fruit does not exhibit expected signs of aging, as demonstrated by lower quantity of ethanol produced during a 3 month storage period. Because the fruit treated with YEA! requires more severe than normal gassing with ethylene to initiate post-harvest degreening, it may be concluded that eth-ylene biosynthesis is reduced by YEA! application in citrus.