愈伤组织形成过程中钙离子与激素诱导效应的关系

RELATIONSHIP BETWEEN Ca^(2+) AND HORMONE EFFECT IN CALLUS FORMATION

实验研究了在胡萝卜、烟草愈伤组织形成过程中,激素诱导作用与钙离子的关系。结果表明:在含有正常浓度的激素和Ca^(2+)的培养基中,0.1—1mmol/L Ca^(2+)螯合剂EGTA抑制愈伤组织鲜重增长78.0%—88.4%; 10—50μmol/L尼群地平及10—60μmol/L异博定等细胞膜钙通道阻断剂分别抑制愈伤组织鲜重增长19.1%—81.9%及17.6%—70.3%。除去上述Ca^(2+)螯合剂及Ca^(2+)通道阻断剂后,受抑制的外植体基本上可恢复生长。在无激素培养基中,10—30μmol/L Ca^(2+)载体A_(23187)可使外植体膨大,使外植体脱分化细胞增多,并出现分生细胞团,初步说明A_(23187)诱导的Ca^(2+)内流可以部分地模拟激素的作用。以膜显示剂氯四环素探测胞内Ca^(2+)分布时发现分裂细胞、脱分化细胞、分生细胞团及愈伤组织区域的细胞荧光较强。以上事实说明在愈伤组织形成中激素诱导效应与细胞内Ca^(2+)有密切关系。

The experiment probed into the relationship between the action of hormones and Ca^(2+) in the callus formation of carrot and tobacco. The results were as follows; 0.1—1 mmol/L EGTA inhibited the increase of the callus fresh weight by 78.4%—88.40% in -the medium containing 2,4-D and 6BA. With Ca^(2+) and hormone present, Ca^(2+) channel blockers Nitrendipine (10—50μmol/L) and Verapamil (10—60 μmol/L) reduced the increase of the fresh weight by 19.1%—81.9% and 17.6%—70.3% respectively. The callus growth recovered after the Ca^(2+) antigonists being removed. In the hormone-free medium with a Ca^(2+) ionophore A_(23187)(10—30 μmol/L),the explants were expanded and the numbers of dedifferentiated cells and meristemoids increased slightly,indicating that A_(23187) was able to mimic the action of hormones partially. A membrane Ca^(2+) probe CTC was used to reveal the intracellular Ca^(2+) distribution and we found that dedifferentiated cells, dividing cells, meristemoids and callus area showed intense CTC fluorescence. The results above suggested that the effect of hormone in the callus formation and intracellular Ca^(2+) may be related closely.