平茬季节对云南松苗木萌蘖与内源激素关系的影响

Effects of Stumping Season on the Relationship between Sprouting and Endogenous Hormones of Pinus yunnanensis Seedlings

【目的】探究不同平茬季节对云南松苗木萌蘖能力的影响,为云南松萌蘖的激素调控提供理论依据。【方法】以不同平茬季节云南松苗木为材料,测定苗木生长指标和内源激素(IAA、GA_(3)、ZT和ABA)含量及比值的变化,并分析内源激素含量及比值与苗高、地径、萌条数、萌条长、萌条生物量的相互关系。【结果】平茬季节对云南松苗木生长有影响,春季平茬苗高、地径、萌条长及其生物量均最大,夏季平茬苗木和萌条长势较差,秋季平茬萌条数最大。平茬季节对苗木内源激素有显著影响,平茬后60和90 d,内源激素GA_(3)和ZT含量较高;在秋季平茬IAA、GA_(3)、ZT、IAA/ABA、GA_(3)/ABA、ZT/ABA和(IAA+GA_(3)+ZT)/ABA均为最大,春季平茬ABA含量最高。主成分分析和聚类分析结果显示:秋季平茬时苗木生长与春季和夏季明显不同;主成分分析中(IAA+GA_(3)+ZT)/ABA、IAA/ABA、ZT/ABA和GA_(3)/ABA对萌条数的作用较大,其中(IAA+GA_(3)+ZT)/ABA的特征向量最大;GA_(3)和GA_(3)/ABA对萌条长的作用较大;ZT、ABA和IAA对萌条生物量的作用较大,其中ZT的特征向量最大。【结论】平茬季节对苗木萌蘖影响显著,且苗木萌蘖是多种激素共同调控的结果;相较于春季和秋季,夏季平茬对萌蘖作用较大的内源激素含量及比值均不占优势。应综合考虑苗木生产用途的需求选择平茬季节,同时可根据研究结果采取相应措施以提高萌蘖能力。

[Purpose]To explore the effects of different stumping seasons on the sprouting ability of Pinus yunnanensis seedlings,so as to provide a theoretical basis for hormone regulation of sprouting and tillering of P.yunnanensis.[Methods]The growth indexes and the changes of endogenous hormone contents and values of IAA,GA_(3),ZT and ABA in P.yunnanensis seedlings in different stumping seasons were measured,and the relationships among endogenous hormone contents and ratios and seedling height,ground diameter,number of sprouts,sprout length and sprout biomass were analyzed.[Results]Stumping in different seasons had an effect on the growth and sprouting of P.yunnanensis seedlings.The seedling height,ground diameter,sprout length and its biomass were the highest in spring,while the seedling and sprout growth were poor in summer,and the number of sprouts was the highest in autumn.The stumping season had significant effects on endogenous hormones.The contents of endogenous hormones GA_(3)and ZT were higher at 60 and 90 days after stumping;the values of IAA,GA_(3),ZT,IAA/ABA,GA_(3)/ABA,ZT/ABA,(IAA+GA_(3)+ZT)/ABA were the largest in autumn,and ABA content was the highest in spring.The principal component analysis and cluster analysis showed that the seedling growth in autumn was significantly different from that in spring and summer;in principal component analysis,(IAA+GA_(3)+ZT)/ABA,IAA/ABA,ZT/ABA and GA_(3)/ABA had a great effect on the number of sprouts,among which(IAA+GA_(3)+ZT)/ABA had the largest eigenvector;GA_(3)and GA_(3)/ABA had a great effect on the sprouting length;ZT,ABA and IAA had a great effect on the sprouting biomass,and the eigenvector of ZT was the largest.[Conclusion]Stumping season has a significant effect on seedling sprouting,and seedling sprouting is the result of joint regulation of multiple hormones.Compared with spring and autumn,stumping in summer has no advantage in the content and ratio of endogenous hormones.The needs of seedling production and use will be comprehensively considered to select the stumping season,and corresponding measures can be taken to improve the sprouting ability according to the research results.