不同浓度的外源NO对刺五加种子激素及酶含量变化的影响

目的:研究外源NO对刺五加种子解除休眠及萌发过程中内源激素及酶的变化规律,为打破刺五加种子休眠和人工栽培提供依据。方法:考察不同浓度(1,5,10,20 mmol·L~(-1))的外源NO供体硝普钠(SNP)处理刺五加种子,而后进行变温层积处理。采用高效液相色谱法检测出在不同层积时间(0,30,50,80,100,130 d)的内源激素赤霉素(GA3),脱落酸(ABA),吲哚乙酸(IAA),吲哚丁酸(IBA)及水杨酸(SA)含量变化。采用酶标仪全程监测体内酶过氧化氢酶(CAT),超氧化物歧化酶(SOD),过氧化物酶(POD),丙二醛(MDA)]水平的变化。结果:在刺五加种子萌发过程中,GA3,IAA,IBA和SA的含量逐渐增大,脱落酸的含量逐渐减小。POD和MDA水平显著下降,CAT和SOD的酶活力显著上升。外源NO可以提高刺五加种子萌发率,缩短种子萌发时间,20 mmol·L~(-1)SNP促进种子萌发效果最为明显,10 mmol·L~(-1)SNP促进种子萌发效果最弱,呈"V"型变化。结论:SNP促进刺五加种子萌发可能通过提高种子萌发过程中的激素和酶的含量,以提高种子内源NO含量而实现。

Effect of Exogenous Nitric Oxide on Plant Hormones and Enzyme Content of Acanthopanax senticosus Seeds

Objective: To investigate the effect of exogenous nitric oxide (NO) on breaking the dormancy of Acanthopanax senticosus seeds and the changes in endogenous hormones and enzymes,and provide a basis for breaking the dormancy as well as artificial cultivation of A. senticosus seeds.Method: Different concentrations (1,5,10,20 mmol·L^-1) of sodium nitroprusside (NO donor) were used to treat the A. senticosus seeds, and then thermophilic stratification was conducted. The content changes of endogenous hormones such as gibberellin (GA₃), abscisic acid (ABA),indolo acetic acid (IAA),indolo butyric acid (IBA) and salicylic acid (SA) at different stratification time (0, 30, 50, 80, 100,130 d) were tested by high performance liquid chromatography (HPLC). The activity change of its in vivo enzymescatalase (CAT), superoxide dismutase (SOD), peroxidase (POD), and malondialdehyde (MDA)] were tested by enzyme-labeled instrument.Result: In the seed germination process of A. senticosus,the contents of GA₃,IAA,IBA,and SA were increased gradually,while the content of ABA was reduced gradually. The enzyme activities of POD and MDA were significantly reduced,and the enzyme activities of CAT and SOD were increased obviously. Exogenous NO could increase the seed germination rate and shorten the seed germination time. The effect of 20 mmol·L^-1 sodium nitroprusside showed the most obvious effect and 10 mmol·L^-1 SNP showed the weakest effect in promoting seed germination,showing an obvious "V" shape for changes.Conclusion: Sodium nitroprusside could promote the seed germination effect of A. senticosus, probably by increasing the content of hormones and enzyme in the stage of seed germination and improving the contents of endogenous NO during germination.