【摘要】 研究了棉花种子发芽过程中，胚根的发育和侧根的发生及赤霉素（ＧＡ３）的调节。结果表明，（１）在对照胚根的发育和侧根的发生过程中，生长素（ＩＡＡ）和三种细胞分裂素（ｉＰ＋ｉＰＡ、Ｚ＋ＺＲ、ＤＨＺ＋ＤＨＺＲ）无论是在下胚轴还是在胚根中，前期（４８ｈ前）含量较高，后期相对稳定，维持在较低水平。（２）赤霉素降低了胚根中过氧化物酶的活性，但是提高了７２ｈ以前吲哚乙酸氧化酶的活性。（３）赤霉素浸种显著的抑制了棉苗胚根的发育和侧根的发生，其抑制作用可能是通过降低下胚轴和胚根中前期生长素和三种细胞分裂素的水平来实现的。更多还原

【Abstract】 The regulation of exogenous GA 3 on the development of primary root and the initiation of lateral roots was studied in this paper during cotton seed germination by using CRI 12 as plant material. The results showed that (1) During the development of primary root and the initiation of lateral roots of the control cotton seedling, the levels of IAA, iP+iPA, Z+ZR and DHZ+DHZR vary greatly in both hypocotyl and primary root, the pattern of which is a curve with a high level before 48 hours and a low and stable level after 48 hours. (2) Exogenous GA 3 decreases the activity of peroxidase and increases the activity of IAA-oxidase in primary root. (3) Exogenous GA 3 profoundly retards the development of primary root and the initiation of lateral roots of cotton seedling. This effect of exogenous GA 3 on primary root and lateral roots is possibly the result of the decrease of the levels of IAA, iP+iPA, Z+ZR and DHZ+DHZR before 48 hours by exogenous GA 3.更多还原