干旱胁迫下小麦根冠生物量变化及其与抗旱性的关系

以12个小麦品种为研究材料，分析了盆栽条件下于生殖生长期进行干旱胁迫后根冠性状的变化。结果表明，干旱胁迫在不同程度上降低了小麦产量、株高、根系和地上部干重，增大了根冠比，同时，减少了穗数，但对干粒重的影响较小。其中，变化比较大的是地上部干重和根冠比。相关分析表明，根系干重、穗数和地上部干重的变化与产量的变化呈极显著正相关，根系干重的变化又与穗数和地上部干重变化呈极显著正相关。这些性状的变化密切关系到抗旱指数(DJ)，除千粒重、根冠比的变化率与DI的相关性未达到显著水平以外，其余性状的变化率与DI达到了显著或极显著相关。在直接影响DI的性状变化中，地上部干重变化率(0．6197)、穗数变化率(0．6025)对DI起着明显的正效应，而根干重变化率(-0．3514)则起负效应，株高变化率的负效应较小(-0．0296)；根系干重、穗数和株高的变化率主要通过对地上部干重的影响，以及地上部干重变化率对穗数和根系干重变化率的影响间接对DI起作用：这些结果说明，在干旱条件下，协调小麦根冠平衡，最大程度发挥根系和地上部叶片的功能，才有利于提高产量.

The change of biomass of the root and shoot under drought stress and its relation with drought-resistance in wheat

The 12 wheat(Triticum aestivum L.) cultivars were used in this experiment,and the changes of characteristics of root and shoot after drought stress at reproduction stage were investigated under pot-cultivated condition. The results showed that the yield, plant height, and dry weight of root and shoot decreased, the ratio of root-shoot(R/S) increased, and the fringe number declined, but 1 000 grain weight changed little by drought stress, in which the more changes were shoot dry weight and R/S. The correlation analysis indicated that the changes of root dry weight, the fringe number and shoot dry weight were most significant positively related to change of yield, and also the change of root dry weight was the same to the fringe number and shoot dry weight. These characteristics were closely related to the drought index(DI), the change ratio of above characteristics were significant closely related to the DI expect for 1 000 grain weight. The change ratio of shoot dry weight(0.619 7) and the fringe number (0.602 5) had a positively direct influence on DI. However, root dry weight change ratio(-0.351 4) did negatively influence on DI, and the plant height change ratio (-0.029 6) had less negative influence on DI. The change ratio of root dry weight, fringe number and plant height had indirectly influence on shootdry weight, and the change ratio of shoot dry weight did also on change ratio of root dry weight, fringe number. These resultes suggested that harmonizing the balance of root-shoot under drought stress, playing the role of root and leaf at most could enhance yield.