60Coγ对春兰根状茎染色体倍性及相关酶活性的影响

本试验以春兰茎尖诱导的根状茎为材料，用60Coγ急性辐照后，研究比较了辐照对诱芽情况、染色体倍性及细胞色素氧化酶（COD）、过氧化物酶（POD）、淀粉酶（AMY）、酯酶（EST）酶活性的影响。结果显示：（1）大于10Gy的γ射线辐照抑制了根状茎的芽诱导及增殖；（2）低剂量辐照（≤7 Gy）处理的部分根状茎出现超二倍体现象，高剂量辐照（≥10 Gy）处理则均出现亚二倍体现象；（3）处理根状茎中的EST酶活性均高于对照，POD和AMY活性在低剂量（≤7 Gy）时高于对照，而COD酶活性在高剂量（≥10 Gy）时高于对照。研究表明，7-10 Gy为临界剂量，可作为春兰根状茎辐照诱变的适宜剂量。

Chromosome Ploidy and Related Enzyme Activities of Cymbidium goeringii Rhizome Induced

After acute irradiation of 60Coγ-rays irradiation of treated on Cymbidium goeringii ‘Songnei', stem tip induction, the bud induction, chromosome ploidy and cytochrome oxidase (COD), peroxidase (POD), amylase (AMY), esterase (EST) enzyme activities rhizomes between different treatments were analyzed. Results showed that irradiation of dose above 10 Gy γ-rays inhibited the bud induction and proliferation of rhizome. Low-dose-irradiation（≤7 Gy）induced hyperdiploid phenomenon, and all with high-dose-irradiation（≥10 Gy）caused hypodiploid. EST activity of Cymbidium goeringii rhizome after the treatment was higher compared to the control, POD activity and AMY activity were higher in low dose (≤ 7 Gy) than that of control, while COD activity was higher in high dose (≥ 10 Gy) than that of control. The results indicated that the critical dose was between 7~10 Gy, which could be used as the optimal dose for irradiation-induced mutation of Cymbidium goeringii.