普通型与短枝型苹果接穗对嫁接幼树根系构型的影响

Effects of Different Growth Type Scions on Root Architecture of Self-rooted Young Apple Trees

以嫁接在‘冀砧2号’自根砧上的‘天红1号’(普通型红富士)、‘天红2号’(短枝型红富士)1年生盆栽苹果幼树为试材,以‘冀砧2号’/‘冀砧2号’为对照,研究不同生长类型品种接穗嫁接在‘冀砧2号’自根砧上的根系构型和内源激素含量差异。结果表明,‘天红1号’接穗植株新梢长度、地上部鲜质量、根系鲜质量和根冠比最高。‘天红1号’接穗植株根系活力显著高于‘天红2号’接穗植株和对照植株。‘天红1号’接穗植株根系体积、根尖数最大;对照植株的根系长度、表面积、根平均直径和根分叉数最大。‘天红1号’接穗植株叶片IAA含量,根系IAA、ZR和GA_(3)含量最高。‘天红1号’接穗植株根系MdPIN1a、MdAUX1、MdARF7和MdYUCCA10相对表达量高于对照和‘天红2号’接穗植株。综合研究结果,与短枝型红富士‘天红2号’相比,普通型红富士‘天红1号’嫁接在‘冀砧2号’自根砧上的树体长势旺,根系发达;不同生长类型接穗梢尖产生生长素的多少及向基运输的生理生化机制差异是造成同一自根砧根系构型差异的主要原因,ZR和GA_(3)参与了根系构型的建成。

One-year-old apple seedlings with different scion-rootstock combinations,marked as‘Tianhong 2’(spur type)/‘Jizhen 2’,‘Tianhong 1’(standard type)/‘Jizhen 2’and‘Jizhen 2’/‘Jizhen 2’were used as experimental materials.The differences of root architecture and endogenous hormone content were measured to explore the effect of scion-rootstock combinations on root characteristics.The results showed that the shoot length,fresh weight of the aboveground and root system,and root-shoot ratio of‘Tianhong 1’/‘Jizhen 2’were the highest.The root activity of‘Tianhong 1’scion plants was significantly higher than that of‘Tianhong 2’scion plants and control plants.The root volume and root tip number of‘Tianhong 1’scion plant were the largest.The root length,surface area,average root diameter and root bifurcation number of the control plants were the largest.The content of IAA in leaves and the content of IAA,ZR and GA_(3)in roots of‘Tianhong 1’scion plants were the highest.The relative expression levels of MdPIN1a,MdAUX1,MdARF7 and MdYUCCA10 in roots of‘Tianhong 1’/‘Jizhen 2’were higher than those o‘f Jizhen 2’‘/Jizhen 2’and‘Tianhong 2’‘/Jizhen 2’.In conclusion,standard type Red Fuji‘Tianhong 1’grafted on the self-rootstock of‘Jizhen 2’had more vigorous tree growth than that of the spur type Red Fuji‘Tianhong 2’.The differences in the amount of auxin produced by the shoot tips of different growth types and the physiological and biochemical mechanisms of transport to the base are the main reasons for the differences in the root architecture of the same self-rooted rootstock.Moreover,ZR and GA_(3)were involved in the formation process of apple root architecture.