云南重楼种子萌发过程内源激素含量及酶活性变化研究

Dynamic Changes of Enzyme and Endogenous of Paris polyphylla Smith var. yunnanensis Seed During Different Stages of Germination

为探讨云南重楼种子萌发不同阶段的酶和内源激素的变化,本研究采用生理生化方法测定云南重楼种子萌发不同阶段超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)、苹果酸脱氧酶(MDH)和6-磷酸葡萄糖脱氢酶(G-6-PDH)活性,以及吲哚乙酸(IAA)、赤霉素(GA_3)、脱落酸(ABA)、水杨酸(SA)、反玉米素(TZ)、茉莉酸(JA)6种内源激素的含量,并分析比较其差异。结果表明,云南重楼种子在即将出苗阶段的SOD、POD活性迅速升高,CAT、MDH和G-6-PDH活性降低;IAA、GA_3含量均在即将出苗阶段显著高于其他阶段,种子休眠解除后ABA含量迅速下降。胚根刚突破种皮阶段,其SA、TZ、JA含量均最高,SOD、POD、IAA、GA_3间呈极显著正相关(P<0.01),MDH与G-6-PDH呈极显著正相关(P<0.01),ABA与GA_3呈显著负相关(P<0.05),SA、TZ、JA间呈极显著正相关(P<0.01),IAA/ABA、GA_3/ABA、SA/ABA在种子休眠解除和出苗阶段均呈上升趋势。综上,SOD、POD、GA_3是种子出苗阶段的关键物质,TZ、SA和JA对种子休眠解除具有重要的影响,IAA/ABA、GA_3/ABA及SA/ABA增大对种子休眠解除和出苗均有促进作用。本研究结果为云南重楼种子繁殖提供了理论依据和实践指导。

The aim of this study is to investigate the changes of endogenous hormone contents and enzyme activities in the seeds of Paris polyphylla Smith var. yunnanensis during germination. The seeds at different germination stages were collected to determine their enzyme activities of superoxide dismutases（ SOD）,catalases（ CAT）,peroxidases（ POD）,malate dehydrogenases（ MDH）,and glucose-6-phosphate dehydrogenase（ G-6-PDH） as well as contents of the six endogenous hormones,namely indoleacetic acid（ IAA）,gibberellic acid（ GA3）,abscisic acid（ ABA）,salicylic acid（ SA）,trans-Zeatin（ TZ） and jasmonic acid（ JA）,respectively. The results demonstrated that during the imminent emergence stage,the activities of SOD and POD increased rapidly,while those of CAT,MDH and G-6-PDH decreased gradually. The contents of IAA and GA3 were significantly higher at the imminent emergence stage than any of other stages,but those of ABA decreased rapidly after release of seed dormancy. When the radicles just broke through the seed coats,the contents of SA,TZ and JA all reached the highest level. During the whole germination stages,significant positive correlation was found among the changes of SOD,POD,IAA and GA3（ P〈0. 01）,between MDH and G-6-PDH（ P〈0. 01）,and among SA,TZ and JA（ P〈0. 01）,but the change of ABA was negatively correlated with that of GA3（ P〈0. 05）. Moreover,the relative ratio of IAA/ABA,GA3/ABA,SA/ABA all showed an increasing tendency during the stages of seed dormancy release and emergence. Taken together,the results indicated that： SOD,POD and GA3 might be critical in germination of the seeds; TZ,SA and JA might participate in regulation of epicotyl dormancy release; increase of the IAA/ABA,GA3/ABA,SA/ABA ratio could promote seed dormancy release and emergence. These results would provide a theoretical basis and practical guidance for Paris polyphylla Smith var.yunnanensis breeding.