苦荞麦群体光分布对植株性状及抗倒性能影响的机理研究

Tartary buckwheat (Fagopyrum tataricum (L.) Gaertn) is an edible and medicinal crop belonging to family Polygonaceae and it is one of the most complete and nutritional foods and rich in minerals, vitamins, proteins, dietary fiber, amino acids, trace elements, and various bioactive phytochemicals. Thus, interest in the use of tartary buckwheat for health benefits is growing; the market demand is increasing day by day. Farmers are paying more attention to increasing the total yield of tartary buckwheat to meet the market requirement, and finally attaining more returns. However, based on investigation and production practice, lodging is one of the important factors that constrains grain yield and quality in tartary buckwheat. Because of the plant trait has a close relationship with lodging-resistancee in tartary buckwheat, the research begin with the traits of root and shoot. A method of using the crop cultivation science, botany, plant anatomy, plant physiology and mechanics of machinery to study the characteristic of light distribution and the relationships between plant trait and lodging-resistance in different populations, and to find the key traits of plant that affecting lodging-resistance, and further to reveal the limiting factors that influence the formation of key traits with lodging resistance. This study has the important theoretical and practical significance on breeding new varieties with lodging-resistance and application and extension of cultivation with lodging-resistance in tartary buckwheat. It also has great scientifc significance for exploring the mechanism of lodging-resistance at the molecular level, cloning functional genes and modifying the key traits with lodging-resistance in the future.

苦荞麦作为一种重要的药食同源作物，具有丰富的营养保健价值。近年来苦荞麦及其功能性制品日益受到消费者的青睐，市场需求量剧增。目前生产上,在大面积种植苦荞麦的过程中，倒伏已成为影响其优质高产的关键限制因素之一。本课题根据苦荞麦植株性状与抗倒间的紧密联系，从植株性状（地上部和地下部）着手，采用作物栽培学、植物学、植物解剖学、植株生理学及机械力学相结合的研究方法，研究不同密植群体的光分布特征，植株各性状与抗倒性的关系，并与植株化学组份和内源激素相结合，试图找到影响苦荞麦抗倒能力的关键性状，进一步探明影响其抗倒关键性状形成的限制因素，对苦荞麦抗倒伏品种的选育及抗倒栽培技术的应用具有重要的理论和现实意义；同时对下一步从分子水平探讨苦荞麦的抗倒机理，克隆功能基因、改良抗倒关键性状具有重大的科学意义。

苦荞作为一种重要的特色杂粮作物，具有丰富的营养保健价值。本项目围绕苦荞群体的倒伏问题，通过三年的研究，明确了影响苦荞倒伏的关键性状及其生理机制，主要结论如下：（1）高产密植条件下，苦荞群体冠层透光率明显降低，高密度群体中、下部冠层的透光率下降更为明显，红光/远红光比值降低。遮荫处理后，群体整个冠层的光合有效辐射显著降低，透光率明显下降，红光/远红光比值降低；（2）随群体密度增加，苦荞株高增加，节间长度变长，茎粗变小，根体积变小。遮荫处理后，苦荞植株性状与密度处理表现出类似的变化趋势，说明密植和遮荫均会影响苦荞植株的生长发育，形成不同的株型结构。改变红光/远红光比值发现，低的红光/远红光比值增加苦荞株高、节间长度，降低茎秆粗度；（3）茎秆机械强度随种植密度增加呈显著降低的变化趋势，高抗品种机械强度和穿刺强度显著高于低抗品种，茎壁厚度、大小维管束数量也以高抗品种较高。木质素在不同抗性品种间差异显著，高抗品种有较高的木质素含量，PAL、TAL和CAD酶活性也显著高于低抗品种。高的红光/远红光比值增加茎秆机械强度、木质素和纤维素含量。内源激素方面，与低抗品种相比，高抗品种GA3含量较低，而CTK含量较高，IAA含量无显著的差异。光质变化可影响苦荞茎秆内源激素含量，调节形态发育，高的红光/远红光比值降低GA3含量，增加CTK含量；（4）倒伏率随种植密度增加显著提高，不同抗性品种间差异显著，低抗品种倒伏率最高；（5）苦荞茎秆第1、2节节间长度、机械强度，子叶节穿刺强度，木质素和纤维素含量与倒伏率呈显著的相关关系，可作为评价苦荞抗倒能力，鉴定其抗倒性强弱的关键性指标。密植条件下，群体光环境发生变化，影响茎秆GA3和CTK含量，使茎秆纤细、细长。同时影响木质素代谢合成的相关酶活性，导致木质素含量降低，机械强度变小，抗倒伏能力减弱。生产上应通过合理群体密度，调控群体光环境，促进抗倒株型结构形成，增加群体抗倒能力，降低田间倒伏率。