半干旱地区小麦群体的根系特征与抗旱性的关系

Relationship between root system characteristics and drought resistance of wheat populations in semiarid region.

对抗旱性能不同的 5个春小麦品种 (分别为A、B、C、D、E)的试验表明 ,在 0～ 1 2 0cm土层中 ,其根密度分别为 66、1 0 4、1 37、1 0 2和 99μg·cm- 3;总根量分别为 78.7、1 2 4 .3、1 64.3、1 2 1 .8和 1 1 8.7g·m- 2 ;产量分别为 2 0 1、2 0 7、1 41、2 1 8和 1 90g·m- 2 .在水分为主导因子的旱作条件下 ,根系过大的品种 ,个体间竞争激烈 ,其群体的抗旱性较差 ;根系较小的品种 ,个体间竞争较弱或无竞争 ,故群体抗旱性较强 .

A field experiment with five spring wheat ( Triticum aestivum) varieties 8275(A),79157(B),8832(C),8624(D) and DX24(E) which have different drought resistance shows that the average root density in 0～120 cm soil layer is 66 μg·cm -3 for A,104 μg·cm -3 for B,137 μg·cm -3 for C,102 μg·cm -3 for D and 99 μg·cm -3 E, and their total root weight is 78.7,124.3,164.3,121.8 and 118.7 g·m -2 ,respectively.The grain yield of these five varieties are respectively 201,207,141,218 and 190 g·m -2 .When water is a primary limiting factor, the drought resistance of wheat is worse for those with large root systems,and an intense competition for water is existed among individuals;but is better for those with small ones, and no competition for water is existed.