[Truncated] High temperature can drastically reduce wheat yields. Therefore, adaptation strategies that minimise the negative impact of high temperature on wheat need to be explored. Transpiration (Tr) may play an important role in dissipating heat through evaporative cooling. This thesis assessed the role of Tr in ameliorating leaf temperature (Tleaf) in wheat in relation to changes in atmospheric vapour pressure deficit (VPD), air temperature (Tair) and soil water, and identified some of the mechanisms underlying the genotypic variability in those responses.
A morpho-physiologically diverse set of 20 wheat genotypes was assessed under ambient and elevated Tair to investigate whether greater water use aids plants to retain its biomass under high temperature. It was expected that the genotypes with greater water use would be superior in maintaing their biomass by inhibiting senescence through greater canopy cooling. A pot experiment was conducted in two partially-controlled glasshouses (ambient and elevated temperature) under wellwatered (WW) conditions. Greater water use and its effect on leaf cooling contributed to greater biomass retention under high temperature, which depended on genotype. Genotypes differed in their capacity to maintain cooler Tleaf, which did not always correlate with the Tr (VPD) response.
|Qualification||Doctor of Philosophy|
|Publication status||Unpublished - May 2015|