根箱法原位分析黄梁木幼苗移栽后的根系生长  

In situ analysis of Neolamarckia cadamba seedling root growth after transplanting using rhizobox

作　　者：吴道铭 张书源 董晓全 古敏 邹璇 WU Daoming;ZHANG Shuyuan;DONG Xiaoquan;GU Min;ZOU Xuan(College of Forestry&Landscape Architecture,South China Agricultural University,Guangzhou 510642,Guandong,China)

机构地区：[1]华南农业大学林学与风景园林学院,广东广州510642

出　　处：《中南林业科技大学学报》2020年第7期9-17,共9页Journal of Central South University of Forestry & Technology

基　　金：国家自然科学基金项目(41807112);广东省自然科学基金项目(2018A030310213)。

摘　　要：【目的】利用活动式根箱在土壤栽培条件下原位动态观察和分析黄梁木移栽后根系的形态和分布变化,解答黄梁木是如何构建根系网络及其根系形态和分布是否存在独特特征的两大问题,以期为黄梁木的水肥管理提供理论依据。【方法】将6个月苗龄的黄梁木实生苗移栽于装有赤红壤的活动式根箱,每10 d利用扫描仪获取0~15、15~30和30~45 cm土层根系生长图像,借助根系分析软件WinRHIZO和Image J分析移栽后40 d内这3个土层的根长、根表面积、根体积、根直径、根分支数和根分支角度等指标,并计算根直径、根深宽比、根分支数和分支角度的动态变化率以及根分支数和分支角度的相关性,最后模拟移栽后黄梁木根系生长变化。【结果】在移栽后40 d内,黄梁木的根长、根表面积、根体积、根直径和根分支数均随时间变化不断增加,根系伸长速率达到21.4 cm·d-1;黄梁木70%的根长、根表面积、根体积和根分支数分布15~30 cm和30~45 cm土层;黄梁木根系总长、根表面积和根体积主要由直径≤1.5 mm的细根贡献,特别是直径≤1.5 mm根系长度占根系总长的百分比大于96%;根系横向伸展速率为0.77~1.5 cm·d-1,纵向伸长速率达2.6 cm·d-1;15~30 cm土层单条二级根产生的三级根数量显著大于0~15 cm和30~45 cm土层的,最大值达58条·二级根-1;二级根和三级根分支角度在60°~80°之间;二级根和三级根的分支角度随着时间变化而不断增大,且二级根和三级根的分支数和分支角度均呈极显著正相关关系(P<0.01),相关系数均大于0.8。【结论】本研究的活动式根箱及相关方法较好地实现了土壤栽培条件下黄梁木根系生长的动态原位观察和分析。黄梁木综合运用不断伸长根系和扩大分支角度两种策略,在移栽后的短时间内长出大量细根,迅速在15~45 cm土层建成较发达的根系网络,形成较强的水分和养分吸收能力。为�【Objective】Aimed to understanding how a root system is formed and whether there are some characteristic features of root architecture and distribution in Neolamarckia cadamba,a flexible rhizobox was established to study the changes in the architecture and distribution of N.cadamba roots under the soil condition with in situ observation and analysis.This study will provide a scientific basis for the irrigation and fertilization management of N.cadamba.【Method】Six-months old N.cadamba seedlings were transplanted in flexible rhizobox which was filled with latosolic red soil.In every 10 days,the images of root growth in 0-15 cm,15-30 cm and 30-45 cm soil layer was collected by the scanner,respectively.The length,surface area,volume,diameter,number and branching angle of root within 40 days of transplanting were analyzed by root system analysers WinRHIZO and Image J.The dynamic changes of root diameter,the ratio of root depth and root width,root number and branching angle and the correlation coefficient between root number and branching angle were analyzed.The growth of N.cadamba root after transplanting was further simulated.【Result】Within 40 days of transplanting,the length,surface area,volume,diameter,and number of root increased with time.The elongation rate of root reached 21.4 cm·d-1.The roots of N.cadamba mostly distributed in 15-30 cm and 30-45 cm soil layers,and these two layers had over 70%of total root length,root surface area,root volume,and root number.The roots of N.cadamba were mainly fine roots(≤1.5 mm in diameter),and these fine roots contributed most of total root length,root surface area,and root volume.In particular,the length of fine roots(≤1.5 mm in diameter)accounted over 96%in total root length.The growth rate of root in horizontal was 0.77-1.5 cm·d-1,and was 2.6 cm·d-1 in vertical.The fork rate of tertiary root reached 58 per secondary root in 15-30 cm soil layer,and it was significantly higher than that in 0-15 cm or 30-45 cm soil layer.The branching angle of secondary root

关 键 词：黄梁木 根系结构 根分支 原位观察 根箱 

分 类 号：S792.99[农业科学—林木遗传育种]