SENESCENCE OF FLAG LEAVES AND EARS OF WHEAT HASTENED BY METHYL JASMONATE

Treatment of flag leaves and ears of wheat plants with MJ (jasmonic ac id methylester) (10(-5) and 10(-4) M) did not increase ethylene produc tion, but it did accelerate senescence as indicated by the loss of chl orophyll. MJ also caused the closure of stomata, and consequently the rates of transpiration and photosynthesis decreased. Early maturity sh ortened the grain filling period, so the thousand grain weight was low er. Although ethylene elicited the same physiologic effects, the syndr ome of senescence by MJ is independent of the former. We conclude that senescence and death in wheat are far from being elucidated; however, MJ and ethylene seem to participate in the phenomenon.