三个Y系中间砧对苹果幼树生长及叶片内源激素含量的影响

Effects of three Y-series interstocks on growth and hormone content in leaves of young apple trees

以Y-1、Y-2、Y-3中间砧嫁接‘长富2号’苹果(Malus pumila)幼树为试材,调查研究不同Y系中间砧对树体生长、枝类组成及叶片内源激素赤霉素(GA)、玉米素核苷(ZR)、生长素(IAA)、脱落酸(ABA)含量的影响,结果表明:3个Y系中间砧对‘长富2号’的株高、砧穗比值、分枝数量和枝类组成影响显著。矮化砧Y-2和半矮化砧Y-1的新梢生长量全年均低于半乔化砧Y-3,而分枝数量和短枝比例显著高于Y-3,结果表明随着中间砧致矮能力的增强,嫁接品种株高和新梢生长量降低,分枝数量和中短枝比例增加,且Y-2、Y-1与嫁接品种‘长富2号’的嫁接亲和性高于Y-3。叶片内源激素含量测定表明, 3个Y系中间砧‘长富2号’幼树新梢速长期顶部叶片ZR、IAA、ABA含量均高于缓长期, IAA、ZR、ABA含量表明与枝条长势呈正相关性;新梢缓长期中部叶片IAA/ZR、IAA/ABA的比值均为Y-3>Y-1>Y-2,与树体矮化性状及分枝性状呈一定的负相关,而顶部幼叶IAA/ZR、(IAA+GA3+ZR)/ABA均为Y-2>Y-1>Y-3,与树体矮化性状及分枝性状呈正相关;不同部位叶片激素比值在Y系间的差异,可能由Y系砧木对激素运输或代谢的调节所致。综上, IAA、ZR及IAA/ZR是Y系中间砧调控分枝及矮化的重要因素。

The effects of different Y-series interstocks on tree growth, branch composition and leaf endogenous hormones were studied, using ’Changfu 2’ grafted into Y-1, Y-2 and Y-3 interstocks, respectively, as materials. The results showed that there were significant differences in plant height, rootstock/scion ratio, branch number and branch composition among three Y-series interstocks. The shoot growth of Y-2 and Y-1 was lower than that of Y-3 in the whole growth period, Y-2 represent dwarfing, Y-1 represent semi-dwarfing, Y-3 represent semi-vigorous, while the number of branches and the proportion of short branches were significantly higher than that of Y-3. With the enhancement of the interstock dwarfing effect, the plant height and new shoot growth of grafted varieties decreased, and the number of branches and the proportion of medium and short branches increased. The grafting compatibility of Y-2 and Y-1 with ’Changfu 2’ was higher than that of Y-3. The determination of endogenous hormone content in leaves showed that the contents of ZR, IAA and ABA in the top leaves of new shoots at the rapid growth period were higher than those of at the slow growth period, which showed a positive correlation with the growth of branches. The ratios of IAA/ZR and IAA/ABA of the middle leaves at the new shoots slow growth period were Y-3>Y-1>Y-2, which were negatively correlated with tree dwarfing traits and branching traits. The contents of IAA, IAA/Zr and IAA/ABA in the top leaves at the shoots slow growth period were Y-2>Y-1>Y-3, which were negatively correlated with tree dwarfing traits and positively correlated with branch traits. The difference in the ratio of hormones in different parts of leaves may be caused by the regulation of Y-series interstocks on hormone metabolism or transportation. In summary, IAA, ZR and IAA/ZR were important factors for Y-series interstocks to regulate branching and dwarfing.