中文摘要：

以白桦细胞为试材，通过在悬浮培养第七天进行MeJA、CaCl2及其互作处理，研究Ca2＋在MeJA诱导白桦三萜合成中的作用。结果表明，MeJA处理后显著促进白桦细胞中总三萜和齐墩果酸的合成，分别于48h达到最高积累量46．90和1．31mg·g-1。MeJA＋EGTA和MeJA＋LaCl3·7H2O处理，均降低了MeJA对三萜合成的促进作用，仍显著高于对照。抗逆酶结果显示，CaCl2和MeJA＋CaCl2处理均不同程度的提高了CAT、PAL和APX的活性，而SOD的活性则受到Ca2＋的抑制；两种钙离子抑制剂加入后显著影响抗逆酶的活性。MeJA处理早期（2h），三萜途径各关键酶基因F粥、聃、阳、BPW、即y显著上调表达。MeJA＋LaCl3·7H2O处理早期（2h）除BPW降低外，BPY、BPX2、SS和SE表达量均高于MeJA单独处理；而同MeJA处理相比，MeJA＋EGTA处理2h，BPW、BPX2、SS、SE和FPS表达量均下调。暗示Ca2＋参与了MeJA诱导白桦防御系统启动和三萜物质合成，但两种Ca2＋抑制剂EGTA和LaCl3在三萜合成中的作用效果和机制存在差异。

英文摘要：

We investigated the role of Ca2＋ in the MeJA-induced biosynthesis of triterpenoid by treating suspending cells of Betula platyphylla with CaCl2, MeJA and combining with inhibitors of Ca2＋. MeJA could promote the synthesis of total triterpenes and oleanolic acid in the cells significantly, which, respectively reached the peak of 46.90 and 1. 31 mg · g-1 after 48 hours＇ treatment. The induction effect of MeJA decreased after treating by MeJA ＋ EGTA and MeJA ＋ LaCl3 · 7H2O. The accumulation amount of oleanolic acid were still higher than that of the control. By analyzing the activity of defense enzyme, the activities of CAT, PAL, APX were enhanced after treated by CaCl2 and MeJA ＋ CaCl2, while the SOD was inhibited by Ca2＋. After adding two inhibitors of Ca2＋, all enzymes were effected significantly. The expression of key enzyme genes in the triterpene pathway such as FPS, SS, SE, BPW, BPYBPX2 was significantly upregulated after two hours＇ MeJA treatment. The expression of BPW was reduced after two hours＇ treating with MeJA ＋ LaCl3 · 7H2O. The expression of BPY, BPX2, SS and SE regulated treated by MeJA. Meanwhile the expression of BPW, BPX2, SS, SE by MeJA ＋ LaCl3 · 7H2O were higher than those and FPS were down-regulated at two hours after MeJA ＋ EGTA treatment compared with MeJA treatment. Therefore, Ca2＋ played a role in triterpenoid biosynthesis induced by MeJA, but two Ca2＋ inhibitors had different effect and mechanism in triterpenoid biosynthesis.