The role of ethylene and l-aminocyclopropane-l-carboxylic acid (ACC) in pollination and senescence of cut flowers of hippeastrum (Hippeastrum x hybridum hort.)

Pollination of hippeastrum flowers did not affect the corolla life span. Only stigma and style from pollinated flowers wilted sooner than those from the unpollinated ones. Pollination or application of ACC to intact pistil accelerated synthesis of ethylene by the pistil only when stigma was mature. This was not observed when immature stigmas were treated. Various parts of the pistil showed different ability to synthesize ethylene after wounding. Production of this gas was the most intensive in the stigma, whereas decreased amounts of ethylene were emitted successively by the upper, middle and lower parts of the style. Increased amounts of ACC were found in pollinated or wounded pistils. Production of ACC was the highest in the stigma, and smaller in the style; amount of ACT decreased toward the basis of the style. The influence of ethylene and ACC on in vivo germination of pollen was also examined. Germintaion of pollen was accelerated by both ethylene and ACC