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This work was aimed at testing the involvement of ethylene in the maturation of grain and senescence of the foliar structures of the wheat inflorescence . Whole wheat ears emitted ethylene to the atmosphere . From pre-anthesis, ethylene emission progressively increased from 0.76 nl g -1 FW h -1 to a peak 1 .53 nl g -1 FW h -1 at the hard dough stage of the grains, to fall to a minimum of 0 .10 nl g -1 FW h -1 at the dormant seed stage . Ethephon increased the ethylene release, hastened the process of grain maturation and senescence of the ears . Aminoethoxyvinylglycine and silver thiosulfate produced the opposite effects . It is concluded that ethylene plays a role in grain maturation and in the senescence of the green bracts of the inflorescence .Abbreviations : Ag+ = silver ion ; AVG = aminoethoxyvinylglycine ; SAM = S-adenosylmethionine ; STS = silver thiosulfate ; TGW = thousand grain weight 107

In this work we present evidence that the drought stress syndrome in the flag leaves and ears of wheat plants, provoked by the production of ethylene (shortening the grain filling period and lowering the grain weight) is reversed by the application of a free radical scavenger, sodium benzoate or the ethylene synthesis inhibitor, aminoethoxyvinylglycine. Rehydration by watering also attenuated the detrimental effect of the water deficit. Consequently, the grain filling period was longer, the grain weight increased, and the total protein content was higher than that in plants watered regularly.

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