[目的]探究云南松幼苗非结构性碳水化合物和内源激素对干旱胁迫的响应规律及其调控机制.[方法]以2年生云南松幼苗为试验材料,采用盆栽称重控水法,将土壤相对含水量分别控制在田间最大持水量的75%~85%(CK)、60%~70%(轻度干旱)、45%~55%(中度干旱)和30%~40%(重度干旱),研究不同干旱胁迫处理下云南松幼苗针叶非结构性碳水化合物(可溶性糖和淀粉)含量、内源激素(脱落酸ABA、生长素IAA、赤霉素GA和玉米素核苷ZR)含量的变化情况以及二者的相关关系.[结果]①随干旱程度的加重,云南松幼苗针叶可溶性糖含量逐渐增加,淀粉含量先升高后降低,可溶性糖/淀粉比值先降低后升高,淀粉分配比例先增后减,可溶性糖分配比例先减后增.②各干旱胁迫处理云南松幼苗针叶ABA含量较CK显著升高,而ZR、GA及IAA含量随干旱胁迫加重均呈下降趋势,IAA/ABA、GA/AB A 和 ZR/ABA比值较CK显著下降.③云南松幼苗针叶可溶性糖含量与ABA含量呈正相关关系,与IAA、GA、ZR含量均呈负相关关系,其中与IAA含量呈显著相关(R2=0.423 0,P<0.05);针叶淀粉含量与ABA、IAA、GA、ZR含量均呈正相关关系,其中与GA含量呈显著相关(R2=0.392 4,P<0.05);针叶可溶性糖和淀粉含量与IAA/ABA、GA/ABA、ZR/ABA比值均呈负相关关系,其中可溶性糖含量与IAA/ABA比值显著相关(R2=0.394 3,P<0.05).[结论]云南松幼苗可通过调整体内可溶性糖和淀粉的相互转化与分配,同时通过积累抑制生长的ABA和降低促进生长的GA、IAA、ZR,进而调整针叶IAA/ABA、GA/ABA和ZR/ABA比值来适应干旱环境.
[Objective]This study explored the regulation mechanism of non-structural carbohydrates and endogenous hormones in Pinus yunnanensis seedling under drought stress.[Method]Two-year-old P.yunnanensis seedlings were selected for treatments with relative soil water content controlled at 75%-85%(CK),60%-70%(light drought),45%-55%(moderate drought)and 30%-40%(severe drought)of the maximum water holding capacity in field by weighing.Contents of non-structural carbohy-drates of soluble sugar and starch and endogenous hormones of abscisic acid(ABA),auxin(IAA),gibber-ellin(GA)and zeatin nucleoside(ZR)in seedling needles under different drought treatments were investi-gated,and their correlations were analyzed.[Result]① With increasing drought,soluble sugar content in needles of P.yunnanensis seedlings gradually increased,starch content and starch allocation ratio first in-creased and then decreased,while soluble sugar/starch ratio and soluble sugar allocation ratio first de-creased and then increased.② ABA content of needles of P.yunnanensis seedlings increased significantly in all treatments compared with CK,ZR,GA and IAA contents showed a decreasing trend with the increa-sing drought stress,while IAA/ABA,GA/ABA and ZR/ABA ratios decreased significantly.③ Soluble sugar content was positively correlated with ABA content and negatively correlated with IAA,GA and ZR contents,of which the negative correlation with IAA was significant(R2=0.423 0,P<0.05).Starch con-tent was positively correlated with ABA,IAA,GA and ZR contents,of which the correlation with GA was significant(R2=0.392 4,P<0.05).Leaf soluble sugar and starch contents were negatively correlated with IAA/ABA,GA/ABA and ZR/ABA ratios,and the correlation of soluble sugar with IAA/ABA ratio was significant(R2=0.394 3,P<0.05).[Conclusion]P.yunnanensis seedlings adapted to drought environ-ment by adjusting conversion and distribution of soluble sugar and starch and IAA/ABA,GA/ABA and ZR/ABA ratios by accumulating growth-inhibiting ABA and reducing growth-promoting GA,IAA and ZR.