β-氨基丁酸诱导气孔关闭机制及其节水效应研究

Water deficiency is one of the key limiting factors of crop yields in the northwestern regions of China. Plant anti-transpirant plays important roles in improving water use efficiency (WUE) in agricultural production. However, there are still some problems of the present anti-transpirant, such as fulvic acid (FA) is nearly unabsorbable for leaf. Recent studies suggest that soil-drenched β-aminobutyric acid (BABA) can prime plant resistance to pathogen, drought and salt stress, etc. Our group previously found that foliar application of BABA could induce stomatal closure, which might function in improving WUE of crops. In this project we plan to use Glycine max (L.) Merr. (Soybean) as a model plant, which is one of the most important economic crops in the northwestern regions. Field and greenhouse experiments will be conducted by combining techniques of plant physiology and cell biology. This project will investigate (1) the spatiotemporal dynamics and dose effect of BABA-induced stomatal closure in soybean; (2) Mechanisms underlying BABA-induced stomatal movement in soybean; (3) Effects of BABA on WUE in soybean and the underlying mechanisms. This project will reinforce our understanding of how BABA can improve WUE in crops through inducing stomatal closure. It will also help to develop new water-saving solutions through the use of effective anti-transpirant in agricultural production and food security.

水资源匮缺是我国西北地区作物产量提升的限制因子。植物抗蒸腾剂对提高农业用水的有效性具有重要影响。近年来，国内外围绕抗蒸腾剂开展了大量研究。然而，已有的抗蒸腾剂大田施用效果大多不及预期或被发现存在明显缺陷[如，黄腐酸（FA）：叶片难吸收]，有待进一步创新。已有证据表明根部浇灌β-氨基丁酸（BABA）促植物抗病、抗旱及抗盐胁迫等。申请人发现叶面喷施BABA可诱导气孔关闭，可能有节水效应。项目拟以西北地区主要经济作物栽培大豆(Glycine max)为实验材料，通过设计田间实验和温室控制实验，结合植物生理生态学和细胞生物学技术手段，研究(1) BABA诱导栽培大豆气孔关闭的时间动态和剂量效应规律；（2）BABA诱导栽培大豆气孔关闭机理；（3）BABA对栽培大豆水分利用效率的影响及其生理生态调节机制。研究结果将揭示BABA诱导气孔关闭提高植物水分利用效率的机制，有助于探索高效蒸腾抑制节水新途径。

水资源匮缺是我国西北地区作物产量提升的限制因子。植物抗蒸腾剂对提高农业用水的有效性具有重要影响。近年来，国内外围绕抗蒸腾剂开展了大量研究。然而，已有的抗蒸腾剂大田施用效果大多不及预期或被发现存在明显缺陷[如，黄腐酸（FA）：叶片难吸收]，有待进一步创新。已有证据表明根部浇灌β-氨基丁酸（BABA）促植物抗病、抗旱及抗盐胁迫等，然而其对植物气孔运动的调控作用及其节水效应研究长期被忽视。项目以西北地区主要经济作物栽培大豆(Glycine max)为实验材料，通过设计田间实验和温室控制实验研究发现：（1）BABA不能直接诱导大豆气孔关闭，高浓度BABA（250 µM）对大豆保卫细胞有毒害作用，导致保卫细胞活力降低甚至消失；（2）叶面喷施100µM BABA不能诱导大豆叶片表面的保卫细胞内脱落酸（ABA）含量增加，但能增强其气孔对ABA响应的灵敏性，进而诱导气孔更快速地关闭；（3）在聚乙二醇6000（0.4 MPa）模拟的干旱胁迫下，叶面喷施100µM BABA能改善叶片光合作用和抗氧化防御体系；（4）大田实验结果表明：在土壤水分亏缺的条件下，叶片喷施喷施100µM BABA能够提高大豆产量和水分利用效率（p＜0.05），其中最佳的施用时间为分枝期，花期次之，鼓粒期施用效果不显著。本项目研究成果揭示：叶面喷施β-氨基丁酸（BABA）促进大豆的抗旱节水，可能与提高大豆气孔响应脱落酸（ABA）的敏感性促进气孔快速关闭及改善叶片光合作用和抗氧化防御体系有关。同时，BABA作为一种有效的能够改善植物响应干旱胁迫的物质，在水分匮缺的条件下能够提高作物产量和水分利用效率，成本低、效果优，具有较好的应用推广价值。