玉米根系活力及吸收面积的空间分布变化

The Space Distribution of the Maize Root Activity and Its Absorbing Area

分别用氯化三苯基四氮唑 ( TTC)还原法和甲基蓝吸附法测定玉米根系活力和吸收面积 ,研究其 0～1 5 cm土层根系的水平分布和离主茎 0～ 2 0 cm范围土壤根系的垂直分布情况。结果表明 ,TTC还原量在离主茎 0～ 2 0 cm的水平方向和离地面 0～ 45 cm的垂直方向上 ,随着离主茎距离的增加和土层深度的加深而降低。TTC还原强度在水平方向上与 TTC还原量的变化趋势类似 ,只是个别生育期 1 5～ 2 0 cm处回升 ;在垂直方向上与 TTC还原量的变化趋势相反 ,随土层深度的加深而增加。同样范围内根系总吸收面积和活跃吸收面积的变化趋势与 TTC还原量相同 ;而比吸收面积和比活跃吸收面积 ,在水平方向上随着离主茎距离的增加而明显增加 。

The space distributions of maize root were studied by measuring the maize root activity and its absorbing area with the methods of TTC reducing and methyl-blue absorption separately. The results indicated that TTC reducing intensity and its amounts gradually decreased from near to far in range of 0～20 cm at the horizontal directions, only at the earlier growth stage, going up again in the range of 15～20 cm. TTC reducing intensity progressively increased with increases of the soil layer depth in the range of 0～45 cm at the vertical directions, but TTC reducing amount decreased. The root absorbing area, total root absorbing area and active absorbing area were reduced with increase of the distance from main stems at the horizontal direction of 0～20 cm range, but the specific absorbing area and specific active absorbing area were increased. And at the vertical direction of 0～45 cm range, total root absorbing area and active absorbing area were decreased as the depth of soil layer increased, obvious changes taken place in the specific absorbing area and specific active absorbing area at different growth stages, both were gradually increased at former growth stages and decreased at earlier stages.