根系构型决定了植物植株固定和资源吸收等很多重要功能,并通过资源的分配确定了植物的根冠比和净初级生产力.对黄河三角洲贝壳堤岛3种优势灌木柽柳、酸枣和杠柳的根系构型进行了研究,并验证了植物根系分支直径的尖细速率和根系分支前后的比例.结果表明:3种植物的根系构型不同,酸枣和杠柳根系主要分布在浅表层,水平根幅与垂直根幅的比值较大,而柽柳的垂直根深所占比例最大;杠柳和酸枣的拓扑指数分别为0.85和0.96,趋向于1,近似于鱼尾形分支,而柽柳的拓扑指数为0.65,接近于叉状分支.平均连接长度以酸枣最大,杠柳次之,柽柳最小.随连接长度增加,酸枣根系相比其他两种植物的尖细速率趋向于平缓.此外,3种植物的分支前后直径都符合Leonardo da Vinci法则.总之,根据根系构型,黄河三角洲贝壳堤岛3种灌木植物可以划分为2类,一类是以根系地表分布,扩大根幅,鱼尾形分支觅养的酸枣和杠柳,另一类则是根系深扎,充分利用地下资源的柽柳,体现了2种不同的生境适应对策.
Root architecture and adaptive strategy of 3 shrubs in Shell Bay in Yellow River Delta
Root system architecture determines many of the vital functions of a tree e.g.stability of anchorage and resource uptake.The shoot:root ratio is determined through the allocation of resources.In this study,the root architecture,root diameter tapering rate and branching ratio of 3 different shrubs,Tamarix chinensis,Ziziphus jujube and Periploca sepium were studied in shell bay in Yellow River delta.The results showed that:root architecture differed greatly among species in terms of rooting behaviour.The ratio of horizontal to vertical root amplitude of Z.jujube and P.sepium was larger than that of T.chinensis,with mainly shallow root system.Root ranching pattern differed by species,with the shrub Z.jujube and P.sepium tending to be herringbone-like (TI =0.96,0.85) and T.chinensis being dichotomous(TI =0.65).The average length of links was very long for all species,with shortest being T.chinensis,longest in Z.jujube.With increasing of link length,the tapering rate of Z.jujube tended to be slower compared to other two shrubs.In addition,we tested the "pipe-stem" theory.In short,the three kinds of shrubs should be divided into 2 root behavior for the adaptive strategies for resource exploration and exploitation.Namely,the horizontal roots expanding,fish-shaped foraging strategy,i.e Z.jujube and P.sepium.The other was T.chinensis with deep root system for full use of underground resource.
shell bayroot architecturetopological indiceslength of link
国家科技期刊平台
NSTL
万方数据
维普
