干旱胁迫下3个油菜品种地上、地下部生长特征与抗旱性的关系

为了探索干旱胁迫下不同抗旱性油菜品种的地上、地下部生长特征与抗旱性的关系，通过土柱栽培试验，对油菜品种DR1、DR2和DR3在不同水分处理条件下不同土层根量、地上部生物量、冠层覆盖面积及抗旱性之间的关系进行研究。结果表明：3个品种在水分胁迫和正常供水条件下产量和根系生物量在品种间均达到显著性差异，3个品种的抗旱能力大小依次为：DR1>DR3>DR2；不同水分处理下油菜的根系主要分布于0~30 cm土层，占根系总量的70%以上；在干旱胁迫下，3个品种DR1、DR2和DR3的总根量分别减少了22.53%、24.17%和24.53%，但仍表现出抗旱性强的品种DR1的根系总量最大,达到12.07 g，其次为品种DR3和DR2；在大于30cm的土层中，DR1的根系量占到总根量的31.5%，这表明根系垂直分布量的多少对抗旱性的影响较大，同时植株冠层面积、总生物量、根系干重与抗旱性的直接通径系数分别为0.5861、0.4514、0.5715，说明除了根系外，大的冠层面积可减少地表蒸发有利于作物抗旱。

Relationship between growth characteristics of above- and under-ground and drought resistance of three rapeseed cultivars under drought stress

In order to explore the relationship between growth characteristics of above- and under-ground and drought resistance of different drought resistance rapeseed varieties under drought stress, through soil column cultivation experiment under the condition of different water treatment, we studied the relationship of root in different soil layer, above-ground biomass and canopy cover with drought resistance of rapeseed varieties DR1, DR2 and DR3. The results showed that under the condition of water stress and normal water, yield and root biomass of all three varieties achieved significant differences and the drought resistance of three varieties as follows: DR1>DR3>DR2. Under different water treatments, the root weight of rapeseeds was mainly distributed in the soil layer of 0~30 cm, accounting for more than 70% of the total root weight. Under drought stress, the total root weight of the three varieties DR1, DR2 and DR3 were decreased by 22.53%, 24.17% and 24.53%, respectively. But, the root weight of DR1 was the greatest and reached 12.07 g, which showed strong drought resistance, followed by DR3 and DR2. In different soil layers, the root weight of the DR1 was higher than that of DR2 and DR3. In the soil layer below 30 cm, the root weight of the DR1 had the largest percentage of the total root weight. This indicated that the vertical distribution of root considerably impacted the yield under drought resistance. Meanwhile, the direct path coefficients of plant canopy area, total biomass, dry weight of roots, and drought resistance were 0.5861, 0.4514 and 0.5715, respectively, that indicated that except for the root system, reducing the surface evaporation was conducive to crop drought resistance.