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

气孔是叶子表面的微小气孔，它允许植物和大气之间进行气体交换。它们对光合作用至关重要，但大部分水蒸气通过叶片气孔的蒸腾作用损失掉了。当水分有限时，气孔调节以防止水分流失，但它们永远不能完全关闭。我们已经用模式植物拟南芥表明，减少气孔的数量可以通过减少蒸腾作用导致的水分流失来提高植物的抗旱性，并有助于保持土壤中的水分。相反，增加气孔数量可以增强蒸发冷却，并有望提高对热应激的耐受性。我们希望将这一策略应用于水稻，这样我们就可以测试减少气孔数量是否可以提高作物的干旱和热胁迫耐受性，这两者在世界许多地方都日益成为产量的主要限制。我们将开展旨在重新引导植物水分流失的实验，以便在不影响植物抗旱性的情况下增强生殖器官的蒸发冷却，这在未来炎热干燥的环境和更高的大气二氧化碳浓度下可能是重要的。我们已经培育出气孔数量减少或增加的水稻植株，并提议测试在干旱或高温条件下种植这些水稻是否能提高收获的粮食总产量。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水稻参与气孔发育的基因变异，并将这些变异纳入我们的研究，并测试它们的抗旱性和耐热性。我们相信，我们的工作将与生产具有更强抗旱和耐热性的水稻作物具有战略意义，并为改善亚洲各地的粮食安全迈出重要一步。我们的项目直接解决了牛顿水稻研究基金计划的以下目标：-对非生物压力（在这个项目中是干旱和热压力）有更强的适应能力。-提高资源利用效率（在本项目中提高了用水效率）。-开发新的研究工具和技术（在本项目中筛选和鉴定用于基因和性状发现的种质）。

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).