乙烯可促使植株上最老的叶子先落已是公认的事,而处在营养生长期的棉苗则属例外。得克萨斯州学院试验站对叶龄和乙烯诱发的脱落关系进行了研究,在一定的条件下,嫩叶、顶生叶、未展开或半展开的叶子比稍老的叶子、基生叶或子叶先落。顶生叶随着乙烯浓度的增大及株龄的增高(从2—5周)而增大脱落的程度或范围。这种反应是由生长激素反应抑制剂促成的。 It is generally accepted that ethylene can promote the first leaves of plants to grow down, with the exception of cotton seedlings in vegetative growth. The Texas State College Experimental Station studied the relationship between leaf age and ethylene-induced shedding. Under certain conditions, young leaves, top leaves, unexpanded or semi-expanded leaves were slightly older than slightly older leaves, basal leaves or cotyledons drop. Top leaves with increasing ethylene concentration and plant age (from 2-5 weeks) and increase the extent or extent of shedding. This reaction is stimulated by growth hormone response inhibitors.