TIBA、LaCl_3、Verapamil和TFP对菜豆下胚轴生长素诱导的导管分化和形成的效应

Effects of TIBA, LaCl_3, Verapamil and TFP on Auxin-induced Tracheary Differntiation and Formation of Bean Hypocotyls

通过ＴＩＢＡ、ＬａＣｌ３、Ｖｅｒａｐａｍｉｌ和ＴＦＰ对菜豆下胚轴导管分化和形成的调控作用，证明生长素、Ｃａ２＋和ＣａＭ是木质部导管分化和形成所必需的。ＮＡＡ能诱导菜豆下胚轴导管的分化；ＴＩＢＡ能抑制生长素类诱导的导管分化和形成；ＬａＣｌ３和ＴＦＰ在导管分化诱导期（最初２４ｈ）具抑制作用；Ｖｅｒａｐａｍｉｌ与ＴＩＢＡ相似，在导管分化诱导期和导管形成期（伤口形成后７２ｈ之内）都有抑制作用。

Ten-day old bean seedlings (Phaseolus vulgaris L. ) were treated with several chemical substances in the way shown in Fig. 1. After 5 days'treatment, bean hypocotyls were cut into upper and lower parts at wound and 2. 0 cm above and below the wound. The two parts were put into freshly boiled lactic acid solutions (80%) for 3 d. Newly formed tracheas between 8 original vascular bundles were counted under microscope (× 50). The results were as follows:The optimum NAA concentration for the induction of trachea formation was 10-4 mol/L(Fig. 2). The key time for induction was the first 24 h (Fig. 3).TIBA inhibited auxin-induced trachea formation in 72 h after wound formation. The maximum inhibition by TIBA occurred in the first 24 h (Table 1 ). LaCl3 had inhibitive action on trachea only when used in the first 24 h (Table 2), and Verapemil did so in 72 h after wound formation (Table 3)although both were Ca2+ channel blockers. TFP, a CaM antagonist, inhibited trachea formation only when used in the first 24 h(Table 4). It was suggested that auxin transport and the presence of CaM and Ca2+ were important for trachea formation in bean hypocotyls. Trachea formation may begin at 24￣ 48 h after wound formation. After 72 h, auxin-induced trachea formation ended, after which inhibitors did not affect auxin-induced trachea formatiom.