【作者】 张岁岐；

【导师】 山仑；

【作者基本信息】 西北农林科技大学 ， 植物学， 2001， 博士

【摘要】 水分不足是干旱半干旱地区农业生产的主要限制因子，这种环境下的农业生产必须以水分的高效利用为中心，为此，除采取工程、农艺措施以减少农田水分的径流、蒸发、渗漏损失外，提高作物本身的水分利用效率（WUE）应是实现作物高效用水的中心和潜力所在。本研究以不同倍性的小麦进化材料和不同玉米品种为材料，在盆栽、管栽和大田条件下，就作物根系行为（根系大小、分布、功能）、根冠关系对其WUE的影响进行了研究，同时以玉米杂交种户单四号为材料在盆栽条件下就N、P营养影响作物根冠关系从而调控其WUE的机理进行了研究。获得如下主要结果：1、在玉米上，叶片水分状况和根源ABA浓度共同控制玉米叶片的气孔行为，且根源ABA浓 度与气孔阻力的关系更为密切，木质部汁液pH也在调控气孔行为方面有作用，pH值的增 加降低了玉米叶片的气孔开度；玉米根源ABA浓度与其叶片的光合和蒸腾速率成抛物线关 系，但由于光合和蒸腾对根源ABA浓度反应的敏感性区间存在差异，因而玉米的叶片WUE 也与其根源ABA浓度成显著抛物线关系，过高或过低的根源ABA浓度均会降低玉米的叶 片WUE；在可以长期产生ABA的情况下，根源ABA浓度与玉米产量和WUE成显著负相 关关系，两者均随根源ABA浓度的增加而降低，且以子粒产量计的WUE对根源ABA浓 度的敏感性要大于以生物量计的WUE对根源ABA浓度的敏感性，虽然根源ABA浓度对 地上部生长的影响要大于对产量的影响；玉米根系生长与根源ABA浓度也成显著负相关关 系，但根、冠生长对根源ABA浓度的敏感性不同，其对根系生长的拟制要小于对冠层生长 的拟制。杂交种户单四号由于在干旱下有相对较低的根源ABA浓度，因而在叶片气体交换 能力、生物量、产量和WUE上均高于其相应亲本，干旱下单叶WUE分别较两个亲本高38％ 和33％，整株水平WUE分别高25％和17％。2、根系水力导度Lp是反映根系吸水能力的重要水力学参数，玉米叶片的光合和蒸腾速率均随 其Lp的增加而线性增加，Lp也与玉米叶片WUE成抛物线关系，过高或过低的Lp均会降 低玉米的叶片WUE，且这种关系存在品种间差异；而Lp与玉米生物量、产量和WUE均 成正相关关系，随Lp的增大而增加，杂交种产单四号与其亲本相比有较高的根系Lp。3、作物的根、冠大小对其水分利用有明显调控作用，在小麦2n→6n进化过程中，小麦根系大 小与其整株水平WUE成显著负相关，WUE随根重的增大而减小，地上部生物量与其整株 水平WUE成抛物线关系，过大或过小的冠部生长均会降低小麦的整株水平WUE，根冠比 与其WUE成负相关关系。这说明在小麦从2n→6n的进化过程中，根系生长存在着对WUE 不利的冗余，而这种根系生长的冗余随染色体倍性的增加而减小，从而使其整株水平WUE 增大。在玉米上，根重和生物量与其WUE成抛物线关系，过大的根系生长反而会降低玉米 的WUE，杂交种户单四号合适的根冠比、深层根系的较多分布有利于促高其水分利用。因11 地冠关系对作物水分刊用的调控 此过大的根系生K反而时水分高效利川付个利影响。4、在小麦从Zn－6n的进化过程中，随染色体倍件的增加，小麦的生物翁呈递增进化趋势，l（根 系生长则呈递减进化趋势（根重、根长、根系表面积均降低），根冠比也呈递减进化趋势，汁 因此造成小麦整株水平WUE呈递增进化趋势，WUE随小麦染色体倍性的增加而增加。5、所有二倍体材料中，以法国黑麦（染色体组型g）的WUE为最高，而以斯卑尔脱山羊草（BB） 的WUE为最低。在其根冠生长方面，冠层生长以法国黑麦为最大，以斯卑尔脱山羊草为最 小；而根系则以一粒小麦和斯卑尔脱山羊草为最大，以节节麦（DD）为最小，且四组材料根 系在土壤剖面的分布存在差异，5（）elf？以下，A、B两染色体组小麦的根重明显大于D、R组 小麦，A、BM组小麦的根冠比也明显大于D、R组小麦。可见，不同染色体组在控制小麦生 长和WUE方面的作用不同。6、N、P影响了干旱下玉米叶片的气体交换能力，表现为提高了干旱下玉米叶片的气孔导度和光 合速率，且N的作用要大于P的作用：N具有同时降低玉米叶片光合作用的气孔和非气孔限 制的作用，而P提高玉米光合则主要是由于降低了于旱下的非气孔限制。施用N、P明显改 变了干旱下玉米的根系行为，表现为降低了干旱下根源ABA浓度，也同时降低了其ZRs浓 度；N、P提高了玉米根系的水力导度，且N的作用要明显大于P的作用；促进了玉米的生 长，但由于P对玉米根系生长的较大促进作用，使得N降低了玉米的根冠比，而P提高了玉 米的根冠比。由于施用N、P对玉米根系行为和根冠关系的影响，因而明显提高了玉米的叶 片和整株水平WUE，且在严重干旱下P的促进作用更为明显。7、较大的根系、较高的根源ABA浓度是作物适应于旱的重要机制，但其对作物在于旱下生存的 重要性要大于其对生产力和水分利用的重要性，因此，通过人为措施减小根系生长、降低根更多还原

【Abstract】 Water availability is a major determinate of crop productivity in arid and semi-arid regions of the world, thus the high use efficiently of water should be center of the crop production in this regions. One solution to this problem is to irrigate in diy environment, i.e. to modify the environment to suit the crops. Another solution is to select and cultivate crops requiring less water for growth (increase crop water use efficiency), i.e. to modify the crop to suit the environment better. Water use efficiency (WUE) may be expressed at various level. A higher WUE at equal water uptake is a desirable trait for crop because, both in rain-fed and in irrigated crops, more biomass or yield will be produced with the available water. Therefore it is not surprising that there have been extensively studied in WUE of crop, but most is focused on the crop responses of shoot, root as a sensor of soil environment change, its effect on WUE is studied less. The present potted piped and field experiments were designed to investigate the effects of crop root behavior (root size .~ profile distribution.~ function .~ concentration of ABA in root xylem sap et al) and root-shoot relations on its WUE, using wheat evolution genotype with different ploidy chromosomes sets and different corn varieties (Zea May) under various water conditions. The major results are as follows: 1. The instantaneous water use efficiency at the leaf level (WUE1) and the long-term water use efficiency (WIJEI) at whole plant level of corn hybrid HuDan 4 is higher than that of its parent under severe drought because of relative lower ABA concentration in root xylem sap, larger root growth and root-shoot ratio, more root distribution in deeper soil layer and higher root hydraulic conductivity(Lp) compared with its parent, which result in higher stomatal conductance ((is) and photosynthesis rate (Pn); WUE1 of HuDan 4 is higher than that of its parent under moderate and irrigated conditions, but its WIJEi is lower than that of parent because of large root growth and higher root hydraulic conductivity which is advantageous to water uptake of root and transpiration loss of leaf. 2. Stomatal behaviour of corn is controlled integratedly by both leaf water status and ABA concentration in root xylem sap under drought conditions , but it is more closely related to ABA concentration in root xylem sap than to the leaf water status. (is of corn decrease with increase of pH in root xylem sap. Pn and transpiration rate (Tr) of corn leaf is parabolic correlated with ABA concentration in root xylem sap. WUEi is also parabola correlated with ABA concentration in xylem sap because the sensitivity of Pn and Tr to ABA concentration in root xylem sap is different. Under long terni drought conditions, corn biomass, yield and WUEI are negative correlated with ABA concentration in root xylem sap, they decrease with the increase of ABA concentration in root xylem IV sap, and the sensitivity of yield WUEI to ABA concentration in root xylem sap are larger than that of biomass WUEI, although the effect of ABA concentration in root xylem sap to biomass production is larger than that to yield. Meanwhile, root growth of corn is reduced by ABA, but its decrease is less than that of biomass. The sensitivity of different corn varieties to ABA concentration in root xylem sap is different, its order is HuDan 4 473?han 4. Therefore, it is possible to increase WIJE by regulating ABA concentration in root xylem sap. 3. Pn and Tr of cont leaf is linearity correlated with its root hydraulic conductivity (Lp), both i更多还原