外源激素对低温胁迫下南美油藤幼苗叶片生理生化指标的影响

Effects of exogenous hormones on physiological and biochemical indexes of Plukenetia volubilis under low temperature stress

【目的】探索南美油藤幼苗的抗冷害机制,为我国南美油藤幼苗低温胁迫适应性研究提供一定的理论参考和支持。【方法】利用脱落酸(ABA)和赤霉素(GA3)两种外源激素作为诱导剂,测定南美油藤幼苗在4℃低温胁迫下不同激素和不同浓度处理下的幼苗叶片膜系统[相对电导率(REC),丙二醛(MDA)含量]、渗透调节物质[可溶性蛋白(SP),可溶性糖(SS)]和氧化酶[超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)]活性等生理生化指标随处理时间的变化。【结果】南美油藤幼苗叶片喷施10μmol/L ABA后经低温胁迫能显著降低其膜系统REC和MDA含量(P<0.05,下同),而喷施10 mg/L GA3能有效降低其MDA含量;南美油藤幼苗叶片喷施10μmol/L ABA后经低温胁迫能显著增加其SP和SS含量,而喷施GA3南美油藤幼苗叶片SP和SS含量的增加效果不显著(P>0.05,下同);喷施10μmol/L ABA后经低温胁迫均能有效提高幼苗叶片SOD、POD和CAT活性,喷施10 mg/L GA3可适当提高其POD活性,5 mg/L GA3能在一定程度上提高其CAT活性,但随着低温处理时间的延长,喷施GA3对南美油藤幼苗叶片中CAT活性增强效果不显著。对7种生理生化指标的Pearson相关性分析结果显示,SOD、POD和CAT 3种氧化酶活性间存在正相关关系,且POD与REC呈负相关,CAT与REC和MDA含量呈负相关,故增强SOD、POD和CAT的活性,可适当降低REC和MDA含量,提高南美油藤幼苗的抗冷害能力。SP和SS均与3种氧化酶活性呈正相关,且SS与REC和MDA呈负相关,因此增加SP和SS含量对南美油藤幼苗抵抗冷害能力有积极的作用。【结论】喷施适当浓度的外源激素ABA(10μmol/L)和GA3(5~10 mg/L)能有效提高南美油藤幼苗的抗冷害能力。

【Objective】Mechanism of Plukenetia volubilis seedlings resistance to cold damage was explored to provide reference for adaptation analysis of P.volubilis seedlings responding to low temperature stress.【Method】In this study,two exogenous hormones,abscisic acid(ABA)and gibberellin(GA3),were used as inducers to determine the changes of physiological and biochemical indicators such as blade membrane system[relative conductivity(REC),the content of malonaldehyde(MDA)],osmotic adjustment substances[soluble protein(SP)and soluble sugar(SS)],oxidase[activity of superoxide dismutase(SOD),peroxidase(POD)and catalase(CAT)]in the leaves of P.volubilis seedlings treated with different hormones concentrations and the treatment times under low temperature stress.【Result】The results showed that 10μmol/L ABA applied to the leaf membrane system of seedlings after low temperature stress could significantly reduce their REC and MDA content(P<0.05,the same below),and 10 mg/L GA3 could effectively reduce the content of MDA.10μmol/L ABA could significantly increased SP and SS content in P.volubilis seedlings osmotic adjustment substance,but the effect of GA3 was not significant in increasing the content of SP and SS under low temperature stress(P>0.05,the same below).Additionally,10μmol/L ABA could effectively improve SOD,POD and CAT activities of seedlings leaves,10 mg/L GA3 could properly improve POD activity and 5 mg/L GA3 could improve CAT activity to some extent,but the effect of GA3 on enhancement of CAT activity was not significant with the extension of time.The Pearson correlation analysis was carried out on the seven physiological and biochemical indexes.The results showed that there were positive correlation relationships among SOD,POD and CAT,and POD was negatively correlated to REC,CAT were negatively correlated to REC and MDA.Therefore,the increase of SOD,POD and CAT activities could decrease the REC and the content of MDA which could improve the ability of cold resistant of P.volubilis seedlings.SP and SS were positively correlated with the activities of SOD,POD and CAT,and SS was negatively correlated with REC and MDA,thus increasing the contents of SP and SS could have a positive effect on the cold resistant of P.volubilis seedlings.【Conclusion】Spraying with appropriate concentration of exogenous hormone ABA(10μmol/L)and GA3(5-10 mg/L)could effectively enhance the ability of cold resistant of P.volubilis seedlings.