钙在IAA诱导绿豆下胚轴原生质体膨大过程中的作用

含钙培养液(对照)和仅用IAA处理的原生质体的体积和~(45)Ca~(2 )放射性强度均无变化。IAA处理含钙培养液中的原生质体,5min后~(45)Ca~(2 )积累明显增多,体积开始膨大。处理30min时~(45)Ca~(2 )积累最多,此时原生质体的膨大效应最好;随后~(45)Ca~(2 )积累和膨大效应逐渐下降。K~ 、Zn~(2 )、Ba~(2 )、Mg~(2 )等也可在一定程度上代替Ca~(2 )使原生质体体积膨大。原生质体的吸水在膨大中起着一定作用。EGTA、LaCl_3和verapamil均抑制IAA诱导的原生质体~(45)Ca~(2 )积累和体积膨大。说明Ca~(2 )可能在6-BA诱导原生质体膨大的过程中起着重要作用。

THE ROLE OF CALCIUM IN IAA-INDUCED SWELLING OF PROTOPLASTS ISOLATED FROM HYPOCOTYL OF ETIOLATED MUNG BEAN SEEDLINGS

This paper studied on the role of calcium in IAA-induced swelling of protoplasts isolated from hypocotyl in etiolated mung bean (Pkaseo-lus radiatus L. ) seedlings. Protoplasts incubated in CaCl2-bearing medium without hormone maintained a constant volume and a consistent intensity of 45Ca2 radioactivity. To treat with IAA, they began to swell and continually swelled to the maximum volume 30 minutes later (Fig. 2). However, the protoplasts could not swell when IAA was added into the medium without CaCl2 (Fig. 1). It was suggested that Ca2 may be necessary for IAA to induce protoplast swelling. And also, IAA enabled the protoplasts to swell in less extent with K , Zn2 , Ba2 or Mg2 instead of Ca2 (Fig. 3). Radioisotope experiments showed that K influx increased when K replaced Ca2 (Fig. 4), and water absorption plays a role in the swelling (Fig. 5). 45Ca2 accumulation in protoplasts treated by IAA was much higher than that of control, and the time course of 45Ca2 accumulation was similar to that of protoplasts swelling (Fig. 6).45Ca2 level and the swelling of protoplasts sharply declined when EGTA, verapamil or LaCl3 was added into the medium (Table 1, 2 and 3). These results indicated that Ca2 may play an important role in lAA-induced swelling.