局部灼伤对小麦幼苗外源茉莉酸吸收与运转的影响

Effects of Localized Wounding on the Transport and Distribution of Exogenous JA in Wheat Seedling

采用示踪技术探索了3 H JA的运输和分配规律及其受伤害胁迫的影响。外源 3 H JA能够在小麦幼苗体内向上和向下运输 ,局部灼伤其运输与分配都发生了改变。从小麦根系饲喂的3 H JA ,在植株内的分布量依序为根 >茎 >叶 ,时间较长 (4h)时分配于心叶的3 H JA大大增加。当叶片受到局部灼伤时3 H JA向地上部的输出量减少 ;但局部灼伤可加快由心叶饲喂的3 H JA的向下运输 ,改变3 H JA在小麦幼苗各部位的分配比率。心叶饲喂短时间 (5min)时 ,3 H JA主要积累在受到伤胁迫的展开叶 (第 2叶 )中。向展开叶 (第2叶 )饲喂的3 H JA向下运输的速率高于向上运输的速率。

Jasmonic acid (JA) is an important signal substance in the induction of plant systemic defense responses. Transport and distribution of exogenous JA and effects of wounding stress on it were investigated by 3H JA and radioisotope technique. The results showed that 3H JA could be transported from root to shoot and also could be transported conversely from youngest leaf to root (Figs.1,2). Distribution of 3H JA from roots to youngest leaf increased by 8 fold after feeding 4 hours (Fig.1). However, changes in transport and distribution of 3H JA occurred when the 2nd leaf was wounded. The transport of 3H JA out of root 5 min after feeding fell to half the level in unwounded plant (Table 1); 3H JA transport out of the youngest leaf increased 24 h after feeding (Table 2). Wounding leaf caused changes in 3H JA distribution. 5 min after feeding, 3H JA was mainly in the wounded leaf (2nd leaf) (Table 2). After feeding 3H JA to mature leaf (2nd leaf), it was transported both upward and downward, with downward transport much faster than the upward one (Fig.3). The rapid transport of 3H JA into wounded leaf and accumulation here demonstrated that an important role of JA in plant defense as a wounding signal.