一氧化氮参与铵硝营养对弱光下娃娃菜幼苗生长及抗性的影响

Effect of nitric oxide involved in the moderate ammonium nitrate nutrition on growth and resistance of baby cabbage seedling under low light

【目的】前期研究表明总氮浓度为5mmol/L,铵硝配比为10∶90可以促进弱光胁迫下娃娃菜幼苗的生长,本试验验证一氧化氮(NO)是否参与铵硝营养缓解弱光下娃娃菜幼苗生长及抗性的调节,以期为实际生产提供理论依据.【方法】以娃娃菜幼苗为试验材料,采用营养液栽培,处理第8d,对其抗氧化酶活性、丙二醛及脯氨酸含量进行测定.【结果】弱光下,单独NO供体硝普钠(SNP)处理后,抗氧化酶SOD活性显著高于铵硝比10∶90处理(CK),丙二醛(MDA)含量显著小于CK,说明SNP可缓解弱光胁迫对娃娃菜幼苗的氧化损伤;铵硝比中添加NO抑制剂(L-NAME,NaN3)和清除剂Hb后,地上地下鲜重及总叶面积较CK减小,SOD活性、MDA和Pro含量显著增加.【结论】NO抑制剂和清除剂逆转了铵硝对弱光胁迫下植株抗氧化系统及细胞膜的保护作用.因此,NO参与了铵硝比10∶90缓解弱光胁迫对娃娃菜幼苗的SOD活性、MDA及Pro含量的调节.

[Objective] Previous study has shown that moderate ammonium： nitrate （10＂ 90,total nitro- gen of 5 mmol/L） could reduce low light stress on baby cabbage seedlings. The experiment verified wheth- er nitric oxide（NO） involved in the ammonium nitrate nutrition to regulate the growth and resistance of ba- by cabbage seedling under low light or not, providing theoretical basis for production. [Method] Baby cab- bages seedlings were used as material and cultivated in nutrient solution for 8 days under low light to meas- ure the antioxidant enzyme activities methane malondialdehyde（MDA） and proline （pro） content. [Result] The results indicated that under low light, seedlings supplied with NO donor sodium nitroprusside （SNP） compared with those treated with ammonium： nitrate at 10：90 （CK）increased SOD activities, decreased MDA content, but the difference in pro content was not significant showing that SNP could reduce oxida- tive damage of low light stress on baby cabbage seedlings. However adding the NO scavenger （Hb） and in-hibitor（L-NAME,NaN3） into the ammonium nitrate solution, fresh weight and total leaf area decreased and the SOD, MDA, Pro increased significantly compared with CK. [Conclusion] NO scavenger and inhibi- tor reversed protective effect of antioxidant system and cellular membrane under low light. NO involved in the moderate ammonium, nitrate regulation of SOD,MDA and Pro content of baby cabbage seedlings under low light.