不同结荚习性大豆品种根系的时空分布特征

Root spatial and temporal distribution characteristics of soybean cultivars with different growth habits

研究不同结荚习性大豆根系的时空分布规律,有助于找到大豆根系生长中关键的时间点和空间位置。以亚有限型品种合丰50和无限型品种合丰55为材料,采用自制的两种栽培装置,于六节期（V6）、盛花期（R2）、盛荚期（R4）、始粒期（R5）、鼓粒期（R6）、成熟初期（R7）分段分层取样,分析大豆根长、根表面积、根体积以及根系干物质量的时空分布特征。结果表明,随着生育时期的推进,两个大豆品种根系的总干重、根系总长度、根系总表面积和根系总体积总体上呈现出单峰增长趋势,峰值均出现在R4至R6期。根系干重密度、长度密度、表面积密度、体积密度在垂直方向总体上随着土层深度的增加而逐渐减小,在水平方向上随着与主茎距离的增加而呈先减小后增加的趋势,并于垂直0-20cm和水平0-5cm的土层中达到最大值,其中垂直0-20cm土层根系的长度密度、表面积密度、体积密度和干质量密度在各生育时期分别占整体根系各指标的49.05%-66.09%、52.07%-66.66%、56.74%-69.73%和79.14%-84.82%;水平0-5cm土层根系的长度密度、表面积密度、体积密度和干质量密度分别占整体根系各指标的28.79%-41.68%、41.12%-59.24%、58.44%-76.64%和88.85%-94.02%。与合丰55相比,合丰50根系较发达、体积庞大、干物质积累多。在大豆高产品种选育中可以把R4-R6期内的根系各项指标作为参考依据。

In order to find the key point in time and spatial location in soybean root growth,root spatial and temporal distribution characteristics of soybean cultivars with different growth habits were studied. Hefeng 50（ semideterminate） and Hefeng 55（ indeterminate） were planted in two kinds of cultivation device,their root length,root surface area,root volume and root dry weight in different layers of vertical and horizontal direction were analyzed at V6,R2,R4,R5,R6,R7 stages. Results showed that total root length,total root surface area and total root volume showed unimodal growth trend peak with the advance of growth stages,the peak appeared at R4 to R6 stage. Root dry weight density,length density,surface area density,and volume density decreased gradually with soil depth increase,while these indicators first decreased and then increased with the increase of distance from the main stem,and they reached a maximum 0- 20 cm in vertical and 0- 5cm in horizontal respectively. Root length density,surface area density,and volume density in the vertical 0- 20 cm soil depth at different growth stages accounted for 49. 05%- 66. 09%,52. 07%- 66. 66%,56. 74%- 69. 73% and 79. 14%- 84. 82% of theirrespective total,and in the horizontal 0- 5cm of distance from the main stem accounted for 28. 79%- 41. 68%,41. 12%- 59. 24%,58. 44%- 76. 64% and 88. 85%- 94. 02% of their respective total. Hefeng 50 had more developed root system,root volume,greater dry matter accumulation than Hefeng 55. Therefore,root indexes from R4 to R6 stage could be used as reference in the high- yield soybean breeding.