外源NO对NaCl胁迫下板蓝根种子萌发和幼苗生理特性的影响

Effects of exogenous nitric oxide on seed germination and seedling physiological characteristics of Isatis indigotica under NaCl stress

目的了解外源NO对NaCl胁迫下板蓝根种子萌发和幼苗生长的影响，以便为板蓝根在栽培生产中遇到的盐害问题提供理论参考和解决方法。方法采用霍格兰营养液培养种子，在60mmol／LNaCl胁迫下，测定不同浓度的外源NO供体硝普钠（SNP）处理后板蓝根种子发芽势、发芽率、发芽指数、活力指数、发芽速率指数、平均发芽时间和幼苗苗高、根长、苗质量和根质量的变化，分析板蓝根叶片丙二醛（MDA）量、超氧化物歧化酶（SOD）和过氧化物酶（POD）活性的变化。结果60mmol／LNaCl胁迫显著抑制板蓝根的种子萌发和幼苗生长；经过0．01～0．5mmol／LSNP处理后，种子萌发和幼苗生长指标均有升高，其中以0．1mmol／LSNP处理时各项指标最高；1．0mmol／LSNP处理时幼苗生长指标显著降低。与60mmol／LNaCl处理相比，0．1mmol／LSNP处理时板蓝根种子发芽率和发芽势分别提高12．91％和63．90％，发芽指数和活力指数分别提高16．71％和44．77％，发芽速率指数提高23．64％，平均发芽时间缩短0．1d；幼苗苗高、根长、苗质量和根质量分别提高43．61％、35．05％、51．79％和82．14％；叶片MDA量降低34．83％，SOD和POD活性分别增加43．78％和39．85％。结论0．1mmol／LSNP能有效地减缓NaCl胁迫对板蓝根种子萌发和幼苗生长的抑制作用，增强叶片抗氧化能力，提高种子及幼苗的抗盐能力；高浓度（1．0mmol／L）SNP处理加剧了NaCl胁迫对板蓝根幼苗的伤害。

Objective To offer the reference and method for salt damage in the cultivation of Isatis indigotica and to study the effects of exogenous nitric oxide （NO） on the seed germination and early seedling growth of I. indigotica under NaC1 stress. Methods Hoagland＇s nutrient solution was used to culture the seeds, and the changes of germination energy, germination percentage, germination index, vigor index, germination velocity index, mean germination time, seedling height, root length, seedling weight, and root weight ofL indigotica, and the changes of the MDA content, the activities of SOD and POD of L indigotica leaves after the trealment with exogenous NO donor, sodium nitroprusside （SNP） at different concentration under 60 mmol/L NaC1 stress were determined. Results Under 60 mmol/L NaC1 stress, the seed germination and early seedling growth of I. indigotica were obviously inhibited, which were increased after 0.014.5 mmoFL SNP trealment and the maximum index was obtained under 0.1 mmol/L SNP treatment, while the seedling growth was markedly reduced after 1.0 mmoFL SNP treatment. Compared with 60 mmol/L NaC1 treatment, the germination percentage and germination energy after 0.1 mmol/L SNP treatment were increased by 12.91% and 63.90%; The germination index and vigor index were increased by 16.71% and 44.77%; The gemaination velocity index was increased by 23.64%; The mean germination time was shortened by about 0.1 d; The seedling height, root length, seedling weight, and root weight were increased by 43.61%, 35.05%, 51.79%, and 82.14%; The MDA content was decreased by 34.83%; The activities of SOD and POD were increased by 43.78% and 39.85%, respectively. Conclusion SNP （0.1 mmol/L） could greatly alleviate the NaC1 stress for the seed germination and early seedling growth ofI. indigotica, enhance the ant-oxidative capacity of leaves, and improve the salt resistance ability of the seed and seedling. But the SNP treatment at high concentration （ 1.0 mmol/L） could seriously damage the seedling of/. indigotica under NaC1 stress.