Climate ready rice: Optimising transpiration to protect rice yields under abiotic stresses

气孔是叶片表面的微小孔隙，允许植物与大气之间进行气体交换。它们对光合作用至关重要，但许多水蒸气通过叶片气孔蒸腾而损失。当水分有限时，气孔会进行调整以防止水分流失，但它们永远不会完全关闭。我们已经用模式植物拟南芥证明，减少气孔数量可以通过减少蒸腾失水来提高植物的抗旱性，并有助于保持土壤中的水量。相反，增加气孔的数量增强了蒸发冷却，并有望增加对热应力的耐受性。我们希望将这一策略应用于水稻，以便我们可以测试减少气孔数量是否可以提高作物对干旱和热胁迫的耐受性，这两种胁迫在世界许多地方都是产量的主要限制因素。我们将开展旨在重新引导植物水分流失的实验，以增强生殖器官的蒸发冷却，而不会影响植物的耐旱性，这在未来炎热干燥的环境中以及大气二氧化碳浓度较高的情况下可能很重要。我们已经培育出了气孔数量减少或增加的水稻植株，并计划测试在干旱或高温条件下种植这些植株是否可以提高收获谷物的总产量。这些实验将在转基因植物上进行，但我们也建议通过非转基因技术分离和研究参与气孔发育的基因中的水稻变体，并将其纳入我们的研究并测试其抗旱性和耐热性。我们相信，我们的工作将对提高耐旱性和耐热性的水稻作物的生产具有战略意义，是改善整个亚洲粮食安全的重要一步。我们的项目直接解决牛顿水稻研究资助计划的以下目标：-更大的弹性，以非生物胁迫（在这个项目中干旱和高温胁迫）。- 提高资源利用效率（在该项目中提高了水资源利用效率）。- 新的研究工具和技术开发（在本项目中，为发现基因和性状而对种质进行筛选和鉴定）。

Stomata are microscopic pores on the surface of leaves that allow gas exchange between plants and the atmosphere. They are crucial for photosynthesis, but much water vapour is lost by transpiration through leaf stomata. When water is limiting, the stomatal pores adjust to prevent water loss but they can never completely close. We have shown with the model plant Arabidopsis thaliana that reducing the number of stomata can improve plant drought resistance by reducing water loss through transpiration, and help to conserve the amount of water in soils. Conversely, increasing the number of stomata enhances evaporative cooling and would be expected to increase tolerance to heat stress. We would like to apply this strategy to rice so that we can test whether reducing stomatal numbers could improve crop drought and heat stress tolerances, both increasingly major limitations to yield in many parts of the world. We will carry out experiments that aim to re-direct plant water loss to allow enhanced evaporative cooling in reproductive organs without compromising plant drought tolerance, which could be important in future hot and dry environments and at higher atmospheric carbon dioxide concentrations. We have already generated rice plants with genetically reduced or increased stomatal numbers, and propose to test whether growing these under drought or high temperature conditions can improve the total yield of grain harvested. These experiments will be performed on genetically modified (GM) plants but we also propose to isolate and study rice variants in genes that are involved in stomatal development through non-GM techniques, and include these in our studies and test them for drought and heat resistance. We believe that our work will be strategically relevant to the production of rice crops with enhanced drought and heat stress tolerance, and an important step towards improving food security across Asia. Our project directly addresses the following aims of the Newton Rice Research funding scheme: - Greater resilience to abiotic stresses (in this project drought and heat stresses). - Improved resource use efficiency (in this project enhanced water use efficiency). - Novel research tool and technology development (in this project screening and characterisation of germplasm for gene and trait discovery).