苹果砧木八棱海棠和M9T337的根系分布及水分输导组织特征

Characteristics of root distribution and water-transportation tissues of apple rootstocks Malus micromalu and M9T337

[目的]本文旨在研究砧木乔化/矮化和抗旱能力差别的生理机制,并探索不同土层深度根水分输导组织结构和导水能力的差别,以期为生产上合理制定栽培管理技术措施提供理论依据和试验证据。[方法]本研究测定了常用乔化砧木八棱海棠和矮化砧木M9T337的地上部分生长情况、根分布,同时测定了枝条和不同土层深度的根的木质部导管特征,并根据木质部水分输导组织特征计算了枝条和不同土层深度的根的导水能力。[结果]八棱海棠的树高、基径、枝条数、枝条长度均显著高于M9T337(P<0.05);八棱海棠在不同区域的根生物量和粗根根长密度均显著高于M9T337(P<0.05),细根根长密度除个别区域外均显著高于M9T337(P<0.05),八棱海棠的根垂直分布范围为0～60 cm,M9T337为0～40 cm;八棱海棠根和茎的导管直径和导水率均显著大于M9T337(P<0.05),根和茎的导管密度显著低于M9T337(P<0.05);两个树种深层根的导管直径和导水率均高于浅层根。[结论]八棱海棠根和茎的导水能力更大,根长密度大,根系垂直分布范围广,是其乔化和抗旱能力强的重要原因。深层根有助于根系吸收深层土壤的水分,可能是提升树木抗旱能力的重要因素。

[Objective]In order to explore physiological mechanisms and drought tolerance of apple rootstock vigorous/dwarfing,the structure and water-transport ability of root system at various soil depth of two common apple rootstock species were investigated,and research was aimed to provide technical support for fruit production management.[Methods]Vigorous rootstock Malus micromalu and dwarfing rootstock M9T337 were used as experimental materials.The growth condition,root distribution,and xylem vessel trait of both branch and root system at different soil depth were measured.Hydraulic conductivity of root and branch was determined based on the xylem vessel traits.[Results]Study results indicated that the major parameters including plant height,basal diameter,and the number and length of branch of M.micromalu were significantly higher than that of M9T337,and both root biomass and root length density of M.micromalu with a vertical distribution of 0~60 cm were significantly greater than that of M9T337 with vertical distribution of 0~40 cm.Vessel diameter and hydraulic conductivity of both root and branch of M.micromalu were significantly higher than that of M9T337,while vessel density of root and branch was significantly lower in M.micromalu,and vessel diameter and hydraulic conductivity of deep roots were greater than that of shallow roots for both species.[Conclusion]M.micromalu possessed more efficient vessels,higher root length density and wider vertical root distribution,which greatly contributed to its vigorous effect and strong drought resistance.The deep root,conducting water absorbing from deep soil,may act as an important factor for improving tree’s drought resistance.