冬小麦根系向水分胁迫层的水分传输研究

项目名称： 冬小麦根系向水分胁迫层的水分传输研究

项目编号： No.50809068

项目类型： 青年科学基金项目

立项/批准年度： 2009

项目学科： 生物科学

项目作者： 沈玉芳

作者单位： 中国科学院水利部水土保持研究所

项目金额： 20万元

中文摘要： 采用隔离式水培柱及土培箱，以黄土区旱地冬小麦为主要指示作物，通过控制上下层水势差、氘水（2H2O）标记和不同土层氮磷养分供应的方法，研究了作物不同生育期根系提水作用及传输量的大小、水势差及养分供应对根系提水作用、根系特性和产量的影响。结果表明，上、下层存在一定水势差是作物根系发生提水作用的基本前提条件，且中度水分胁迫处理下作物根系提水作用强于重度水分处理；施氮磷对作物根系提水作用具有显著调节作用，但无论施于上层还是下层冬小麦根系提水作用均在扬花期或灌浆期达到顶峰, 随后又迅速下降，随生育期呈单峰变化规律，且以氮、磷配施处理一夜间和全生育期提水作用最强；相同水肥条件下，水分敏感型XN979冬小麦根系提水作用及水分利用效率均低于抗旱型CW134；冬小麦全生育期根系提水总量与上层根系参数的相关性要大于下层根系；与地上部生物量、千粒重和穗粒重也呈正相关关系；研究结果充分证明了氮磷养分供应对旱地作物不同生育期提水作用及传输量大小的影响；基本明确了不同水势差下作物不同生育期根系提水作用的强弱；为从植物根系提水-土壤养分系统进一步理解黄土区旱地作物利用土壤剖面深层水分而维持上层根系生存及活性的策略。

中文关键词： 冬小麦；根系提水作用；氘标记；水势差；养分供应

英文摘要： Whether root hydraulic lift is the living strategy of plant suffering from drought stress of the upper layer of soil，is currently a key research topic at home and abroad. Nutrition solution column experiment and soil column experiment were conducted to study the root hydraulic lift of crops in the dryland of Loess Plateau. In the study the stable isotope deuterium was used to obtain more precise results through adding deuterium oxide to the lower layers of the columns. The water potential gradients and nutrient supply were controlled through reasonable experiment designs to understand the effects of water potential difference upon root hydraulic lift, and to clarify if nitrogen and phosphorus nutrient has a role on hydraulic lift during the different growth period of crops. The results showed that the water potential gradient between the upper layer and the lower layer was the premise of root hydraulic lift. The hydraulic lift of crops under moderate water stress was higher than under heavy water stress. Nitrogen and phosphorus nutrients have enhancement effects on hydraulic lift. And the effect on overnight and whole growth period hydraulic lift was best when the nitrogen and phosphorus were supplied together. The hydraulic lift showed a single peak, highest at flowing or filling stage, for winter wheat in different fertilization treatments. The hydraulic lift and water use efficiency of water-sensitive winter wheat variety (XN979) were lower than drought-resistant variety (CW134) with same water and nutrient treatments. For winter wheat, the correlation coefficients of whole hydraulic lift with top layer root parameters were better than with lower layer root ones. And they were positive with shoot biomass, 1000-grain weight and grain yield. All these results indicated that nitrogen and phosphorus nutrient can enhance the hydraulic lift during the different growth period of crops, and made it clear that the water amount from hydraulic lift of crops and the effects of water potential gradients upon root hydraulic lift. It is obvious that the research can, from the hydraulic lift to nutrient supply, further the understanding of the strategy crops using the water existed in the deeper soil layers to keep upper root survive and activity in the dryland of Loess Plateau.

英文关键词： Winter wheat; Root hydraulic lift; Deuterium labelling; Water potential difference; Nutrient supply