陕北枣树‘七月鲜’细根形态的季节变化

Seasonal Variations of the Fine Root Morphology of “Qiyuexian” Jujube in Northern Shaanxi

以‘七月鲜’枣树(Zizyphus jujuba)为研究对象,在枣树不同生长时期(萌芽期、展叶初期、展叶中期、全叶期、果实成熟期、落叶前期)用完整土块法采集枣树完整根系并按根序进行细根分级。根系扫描仪结合分析软件获得各根序细根长度、表面积、直径等参数。结果表明:1)不同物候期枣树1、2级细根之间的比例均大于2、3级细根之间的比例。枣树1、2级细根比例在5.2~6.2之间,2、3级细根比例在2.7~3.3之间。不同物候期枣树1、2级细根以及2、3级细根分支比之间差异均不显著(P>0.05)。2)‘七月鲜’枣树不同物候期细根直径和组织密度均表现为1级根<2级根<3级根。1级根、2级根和3级根直径和组织密度均在萌芽期较小,落叶前期较大,导致生物量增加为后一年展叶前的根系生长准备养分。3)1级根、2级根和3级根比表面积、比根长的最大值均出现在萌芽期,并且在果实成熟期均出现峰值。除细根分支比外,‘七月鲜’枣树细根形态在不同物候期具有明显变化,可为枣树地下管理提供理论依据。

The objective of this study was to examine the morphological variations of the fine roots of ＂Qiyuexian＂,a cultivar of jujube growing in Northern Shaanxi, China, in different developmental stages （bud leaf,early-and middle-period of leaf expansion, full leaf, fruit ripening, and leaf falling stage）. The complete fine roots were collected by excavating soil blocks and ranked by root order. The fine root samples were scanned by the Espon scanner,Win-RHIZO system was used to obtain root parameters such as total length,surface area,volume and average diameter. The results showed that 1） in different developmental stages,the ratios of the first order roots to the second ones （ranged from 5.2 to 6.2） were higher than those of the second ones to the third ones （2.7 to 3.3）. Differences in branching ratios of the first and sec- ond roots,as well as the second and the third roots were not significant （P〉0.05）. 2） Root diameters and tissue densities of the roots with different orders increased with the increase of the root order （1st〈2nd〈 3rd） ,which were lower in bud leaf stage and higher in leaf falling stage to accumulate nutrients for the root growth in the next year. 3） The maximum values of specific root length and specific surface area appeared in bud leaf stage,while peak values were also observed in fruit ripening stage. These results suggested that the seasonal variations of the fine root morphology of Qiyuexian had obvious changes in different phenological periods, which could be considered as a theoretical basis for the underground management of jujube trees.