Impact of Ethylene and Abscisic Acid on Programmed Cell Death in Endosperm and Grain Filling of Wheat (Triticum aestivum L.)

Programmed cell death (PCD) is an important physiological activity of plants in adapting to the external environment and maintaining metabolism. However, the mechanism of hormone regulating PCD and nutrient accumulation in endosperm cells during wheat growth needs to explore more research. In this study, the hormone regulation of PCD in wheat endosperm and grain filling under post-anthesis drought stress was studied through spraying ethylene synthesis inhibitor cobalt nitrate (CN) and abscisic acid (ABA) synthesis inhibitor fluridone (FU). The results showed that CN treatment reduced the content of 1-aminocyclopropane-1-carboxylic acid (ACC) (23.6%) and DNA hydrolase activity (6.1%), while increased the viability of endosperm cells, the maximum number (7.1%) and DNA content (5.4%) of endosperm nuclei. Besides, it also up-regulated the expression of ethylene receptor and dad1, delayed the change of nuclear shape, and prolonged the duration of high-filling-rate period (12.1%), leading to increased grain weight (6.4%). However, FU treatment reduced the content of ABA (12.3%), the maximum number (5.1%), and DNA content (7.3%) of endosperm nuclei. Besides, it also down-regulated the expression of ethylene receptor and dad1, increased ACC content (15.6%) and DNA hydrolase activity (15.6%), accelerated the change of nuclear morphology, and shortened the effective filling period (8.1%), leading to reduced grain weight (8%). This study explored the role of plant hormone regulation in wheat and urge for more for sustainable agriculture.