Determination of the extent to which anatomical stomatal characters determine leaf transpiration, temperature and CO2 assimilation in wheat

已知气孔密度在物种之间和物种内变化很大（Weyers & Lawson，1997）。增加每单位叶面积气孔数的操作不仅具有用于光合作用的更大CO2扩散的潜力（Tanaka et al.，2013），但也可以提高叶片冷却，确保叶片保持在光合作用的最佳温度。另一方面，数量的减少可以提高水的利用效率（Franks等人，2015）。因此，气孔密度提供了一个潜在的目标操纵，改变植物和大气之间的CO2和水通量。然而，如上所述，密度本身并不能决定气孔导度，气孔功能也必须考虑。气孔必须适应不断变化的环境条件（例如阳光和阴影斑点），气孔响应的速度极大地影响气体通量（Lawson et al 2010; Lawson & Blatt，2014）。气孔密度也被认为与气孔大小密切相关，较大的气孔密度与较小的气孔相关，通常认为较小的气孔对环境线索的反应更快（McAusland et al. 2016），突出了解剖学和功能之间的密切联系。增加的气孔导度以及因此的蒸腾作用已经显示导致增加的蒸发叶冷却和产量（Lu等人，1998年）。此外，增加气孔对环境信号的响应是一种可以导致提高冠层温度降低和产量的方法。因此，筛选小麦种质的气孔解剖和行为的差异，在选定的环境变化，可以帮助确定基因型与所需的冠层温度特性。本研究的目的是表征气孔特征和反应，使最佳的叶温和光合作用在小麦MAGIC人口，以确定新的遗传目标小麦育种。

Stomatal density is known to vary significantly between and within species (Weyers & Lawson, 1997). Manipulations to increase stomatal numbers per unit leaf area has not only have the potential for greater CO2 diffusion for photosynthesis (Tanaka et al., 2013) but could also enhance leaf cooling, ensuring the leaf is maintained at temperatures optimal for photosynthesis. On the other hand reductions in numbers could increase water use efficiency (Franks et al., 2015). Stomatal density therefore offers a potential target for manipulation, for altering CO2 and water fluxes between the plant and atmosphere. However as described above density alone does not determine stomatal conductance and stomatal function must also be considered. Stomata must adjust to changing environmental conditions (e.g. sun and shade fleck) and the speed of stomatal responses greatly influences gaseous fluxes (Lawson et al 2010; Lawson & Blatt, 2014). Stomatal density is also thought to be closely correlated with stomatal size, with greater stomatal densities being correlated with smaller stomata and smaller stomata are generally assumed to be faster in their responses to environmental cues (McAusland et al. 2016) highlighting the close link between anatomy and function. Increased stomatal conductance, and therefore transpiration, has been shown to result in increased evaporative leaf cooling and yield (Lu et al., 1998). Additionally, increased stomatal responsiveness to environmental cues is one approach that can lead to improved canopy temperature reductions and yield. Thus, screening wheat germplasm for differences in stomatal anatomy and behaviour under selected environmental changes can help identify genotypes with desired canopy temperature characteristics. The aims of this research are to characterize stomatal features and responses that allow optimal leaf temperature and photosynthesis in a wheat MAGIC population in order to identify novel genetic targets for wheat breeding.