玉米根系活力杂种优势及其与光合特性的关系

Heterosis of Maize Root Activity and Its Relationship with Photosynthetic Characteristics

对大田不同水分处理条件下玉米杂交种及其亲本在经济产量形成期的根系活力及其衰退的杂种优势进行了研究,并分析了根系活力与叶片光合特性之间的关系。结果表明,水分亏缺显著降低了玉米的根系活力;充分供水和水分亏缺条件下,玉米杂交种根系活力都具有显著的杂种优势;杂交玉米种根系活力衰退速率具有显著的负优势,抽雄后灌水能够显著降低玉米根系活力衰退速率。杂交玉米种在抽雄期各水分处理下的光合速率显著大于亲本;玉米根系活力与光合速率之间具有显著的正相关关系,随着根系活力的增高,玉米光合速率、气孔导度和蒸腾速率均增高。因此,杂交种较高的抗旱性是根冠共同作用的结果。在玉米育种和栽培中,要充分地考虑到根系对地上部生理活性的影响。

The use of heterosis was an important method to increase the yield of maize, but the studies of heterosis was centralized in the shoot of maize, whether the root activity has heterosis and the relationship of root activity and photosynthetic characteristics were not clear. The present field shelterout rain experiment with hybrid maize and its parents under three soil water conditions was designed to study the heterosis on root activity and its declined properties and its relationship with photosynthetic characteristics. The root activity at the start of Head stage and at one month after Head stage, the photosynthetic characteristic and the root activity declined value were measured. The results indicated that for all the three maize genotypes, root activity decreased under drought stress. The root activity had obvious heterosis regardless drought stress or not at two stages, the heterosis on root activity declined under drought stress at the start of Head stage. The root activity declined rate has negative heterosis, root activity declined rate decreased under drought stress, and irrigation after Head stage distinctly reduced the rate of root activity declined. The photosynthetic rate of hybrid was larger than its parents. Analysis results showed that there were significant positive correlation between root activity and photosynthetic characteristics, which meant photosynthetic parameters increased with the in crease of root activity. Therefore, the higher drought resistance of hybrid resulted from the combination of root and shoot, the influence of root activity on the shoot physiologic activity should be adequately considered in the breeding and planting practice of maize.