外源Ca~(2+)及NO供体硝普钠(SNP)对盐胁迫下紫苏种子萌发及幼苗抗氧化酶活性的影响

目的:通过对紫苏种子萌发及幼苗生理特性的研究,寻找提高紫苏种子及幼苗在盐胁迫条件下抗性能力的途径。方法:测定在外源Ca2+及NO供体硝普钠(SNP)处理后,NaCl胁迫下紫苏种子的发芽势(Gv)、发芽率(Gr)、发芽指数(Gi)和活力指数(Vi),并对紫苏幼苗总生物量以及叶片的丙二醛(MDA)含量、超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性进行测定。结果:100 mmol.L-1的NaCl胁迫下的紫苏种子萌发受到显著抑制,但是经过Ca2+和SNP处理后,萌发指标均有升高。外施10 mmol.L-1的Ca2+或0.1 mmol.L-1的SNP都能够有效的缓解NaCl对紫苏种子及幼苗造成的胁迫伤害,经过SNP,Ca2+的复合处理后,效果最为显著,各项指标均达到最大值,发芽势为65.1%,发芽率为89.3%,发芽指数为13.9,活力指数为为0.110 9。复合处理提高了幼苗的总生物量,降低了叶片的MDA含量,显著的提高了SOD,POD,CAT的活性,其结果分别达到0.84,5.71,4.92 U.mg-1,但是乙二醇双(2-氨基乙醚)四乙酸(EGTA)却显著的抑制了SNP对盐害的缓解作用。结论:10 mmol.L-1的Ca2+和0.1 mmol.L-1的SNP的复合处理能够有效的减缓NaCl胁迫对紫苏种子及幼苗产生的伤害,提高了种子及幼苗的抗盐能力。NO可能通过激活紫苏细胞质膜Ca2+通道促进Ca2+的吸收,改变胞内Ca2+浓度来发挥其对NaCl胁迫伤害的缓解作用。

Effect of exogenous Ca2+ and NO donor SNP on seed germination and antioxidase activities of Perilla frutescens seedlings under NaCl stress

Objective :In order to find a method for improving the salt resistance of seeds and seedlings for Perilla frutescens under NaCl stress, seed germination and physiological characteristics of P. frutescens seedlings were studied. Method : Several physiological indexes of P. frutescens seeds treated by Ca²⁺ and sodium nitroprusside (SNP) under NaCl stress like the germination vigor, germination rate, germination index and vigor index were measured. And other indexes like the biomass of the seedlings, the content of malondialdehyde (MDA) in leaves, the activities of superoxide (SOD), peroxidase (POD) and catalase (CAT) were also measured. Result : The germination of P. frutescens seeds under NaCl stress was inhibited obviously. But after the treatment with Ca²⁺ and SNP, all of the germination indexes increased. And the seeds that treated with SNP+Ca²⁺ had the most significantly increase in all indexes. The germination vigor was 65.1%, the germination rate was 89.3%, the germination index and vigor index were 13.9 and 0.110 9, respectively. The content of MDA decreased after the treatment. The activities of three enzymes include SOD, POD and CAT were increased by the treatment and get the maximin 0.84, 5.71 and 4.92 U·mg^-1 respectively. And the EGTA showed an obvious inhibition to the effect of SNP on P. frutescens. Conclusion : SNP (0.1 mmol·L^-1) and Ca²⁺ (10 mmol·L^-1) could significantly alleviate the damages to the seeds and seedlings of P. frutescens under NaCl stress, and promote the salt resistance of the seeds and seedlings. These results might suggest that exogenous NO might enhance P. frutescens salt resistance and alleviate salt injury possible by enhancing Ca²⁺ influx by activating Ca²⁺ channels and improving concentration of Ca²⁺ of P. frutescens seedlings.