砒砂岩区不同留茬高度及坡向下沙棘根系分形特征

为提高内蒙古砒砂岩区沙棘(Hippophae rhamnoides)人工林根系的生长能力,对东(E)、南(S)、西(W)、北(N)不同坡向沙棘植株进行了距地表0、10、15、20 cm(即a、b、c、d)留茬高度处理,而根系分形特征是植物根系构型应对环境异质性的表型可塑性,为反映沙棘根系对不同坡向不同留茬生长环境的适应结果,基于分形理论在砒砂岩区对东、西、南、北不同坡向下留茬后的沙棘人工林的全根、主根、一级侧根及二级侧根分形特征以及根系和土壤含水率关系进行研究,以未平茬沙棘为对照(即e)。结果表明,(1)不同坡向相同留茬下沙棘根系分形维数(D)变化为E>N>W>S;土壤含水率为E>N>W>S,这与根系分形维数变化规律一致。(2)相同坡向不同留茬下沙棘根系分形维数(D)变化为c(留茬15 cm)>b(留茬10 cm)>a(留茬0 cm)>d(留茬20 cm)>e(未平茬)。(3)不同坡向不同留茬下沙棘根系各级分形维数变化为D3(二级侧根)>D2(一级侧根)>D1(主根),且D3与D呈显著正相关。(4)在相同坡向不同留茬下土壤含水率变化为:c

Fractal Features of Hippophae rhamnoides Roots under Different Stubble Height and Slopes in Soft Sandstone Area

To improve the growth ability of Hippophae rhamnoides artificial forest roots in the sandstone region of Inner Mongolia,the plants of Hippophae rhamnoides from different slopes to the east(E),south(S),west(W)and north(N)were respectively treated with stubble height of 0,10,15,20 cm(a,b,c,d)above the ground.While the fractal characteristics of root system were the phenotypic plasticity of plant root configuration to cope with environmental heterogeneity.In order to reflect the adaptation results of Hippophae rhamnoides root system to different stubble growth environment,which is based on fractal theory,the fractal characteristics of the whole root,main root,primary lateral root,secondary lateral root as well as the relationship between root and soil moisture content of Hippophae rhamnoides were studied in the area of sandstone region.The plants with open stubble(e)were regarded as contrast group.The results showed that:The variations of Hippophae rhamnoides roots fractal dimension were in orders of DE>DN>DW>DS of same stubble under different slopes.Soil water contents were eastern slopes>northern slopes>western slopes>southern slopes of same stubble under different slopes,which were consistent with the roots fractal dimension;The variations of roots fractal dimension were Dc(15 cm stubble height)>Db(10 cm stubble height)>Da(0 cm stubble height)>Dd(20 cm stubble height)>De(open stubble)of different stubble under same slopes;Hippophae rhamnoides roots fractal dimensions at different levels of D3(secondary lateral root)>D2(primary lateral root)>D1(main roots)under different stubble and slopes.There was a significant positive correlation between D3 and D;Soil water contents were c