Morphology,Distribution And Physiological Changes Of Apple Roots In Apple/white Clover System

Interspecies relationship research is the core issue in the research of agroforestry system.At present,the research on the relationship between the subterranean species is still weak.So far,how the fruit trees and forage components change the morphology,distribution and physiological changes of the root system in the orchard compound system.It is not clear that the competition/cooperative mechanism affecting species nutrition is unknown.In this study,the apple/white clover composite system was used as the research object,based on the root box cultivation experiment.Dynamic,continuous and quantitative research methods were used to analyze the root morphology,spatial distribution,and physiology of the fruit tree components of the apple/white clover compound system.The characteristics and laws of change provide the basis for further revealing the interspecific interaction mechanism between orchards and grasses.The main conclusions are as follows:(1)The topological indexes of roots of two young apple trees were all close to 0.5,which were close to forked branches.However,compared with apple monocropping treatments,the roots of the apple tree saplings in composite system had a tendency to change to fish tail;The total number of root connections in the young apple tree system was significantly higher than that of apple monocropping,but the number of external links in the root order was lower than that of apple monocropping.Intercropping white clover increased the fractal dimension of the apple root system in the composite system,but reduced the composite system.Fractal abundance of apple root system.(2)Compared with apple monoculture,the morphological parameters of apple saplings in diameter and RL,RSA,and RB were significantly changed in the interspecific interaction environment.D1,D2,D4,D5 There were significant differences in the morphology of root size and I,II,IV roots and monocropping apple roots.White clover had different degrees of effect on the root growth and development of different apple functions in the apple/white trifoliate system.(3)In the vertical direction,compared with apple monocropping treatments,the effects of white clover on the total RB,RL,and RSA of apple saplings in the composite system are different.The overall presentation of the composite system is that of apple monoculture,but During the autumnal growth period,the compound system>single-cropping apple treatment;the RB,RL,RSA distribution of the young apple tree in the composite system was higher in the 0-30 cm soil layer than in the 30-60 cm soil layer,and the diameters of the young apple tree in the composite system were in different periods.The vertical distribution has different degrees of displacement,and the distribution strategy of the autumnal growth period is the most significant.(4)In the horizontal direction,compared with apple monocropping,in the apple/white trifoliate complex system,the horizontal distribution of RBD,RLD,and RSAD in the weed grass area is smaller than that of the non-grown grass area and apple monoculture at each growth stage,ie Sapling area <grass area<Apple monoculture;D1 and D2 diameter stages RB,RL,RSA in each growth period in the apple spring growth period,during the autumn growth period,the white clover increased the area d≤2mm fine roots Biomass distribution ratio.(5)Compared with apple monoculture,in the apple/white clover interaction,the root activity,nitrate reductase activity,and active absorption area of young apple trees with different diameters and different root sequences significantly changed;The D2 and D3 diameters and II,III,and V all had significant differences;the white clover leaves had the greatest influence on the absorption capacity of apple roots with different d ≤ 3 mm and apple/white clover.(6)The dynamic changes of apple root activity and active absorption area during apple/white clover interaction were as follows: autumn shoot growth period> spring seedling growth period> deciduous period,root nitrate reductase: defoliation period> autumn shoot growth period.> Slight growth period;Compared with apple monocropping,the apple saplings in each growth stage have five diameters,and the white clover increases the root vigor of 0<d≤2mm,which is promoted during the growth period and the deciduous period of autumn.The activity of nitrate reductase in apple young roots with d≤2mm was affected.The effect of white clover on the active absorption area of apple roots was increased in different degrees.