The Plant-Transpiration Response to Vapor Pressure Deficit (VPD) in Durum Wheat Is Associated With Differential Yield Performance and Specific Expression of Genes Involved in Primary Metabolism and Water Transport

Abstract

The regulation of plant transpiration was proposed as a key factor affecting transpiration efficiency and agronomical adaptation of wheat to water-limited Mediterranean environments. However, to date no studies have related this trait to crop performance in the field. In this study, the transpiration response to increasing vapor pressure deficit (VPD) of modern Spanish semi-dwarf durum wheat lines was evaluated under controlled conditions at vegetative stage, and the agronomical performance of the same set of lines was assessed at grain filling as well as grain yield at maturity, in Mediterranean environments ranging from water stressed to good agronomical conditions. A group of linear-transpiration response (LTR) lines exhibited better performance in grain yield and biomass compared to segmented-transpiration response (STR) lines, particularly in the wetter environments, whereas the reverse occurred only in the most stressed trial. LTR lines generally exhibited better water status (stomatal conductance) and larger green biomass (vegetation indices) during the reproductive stage than STR lines. In both groups, the responses to growing conditions were associated with the expression levels of dehydration-responsive transcription factors (DREB) leading to different performances of primary metabolism-related enzymes. Thus, the response of LTR lines under fair to good conditions was associated with higher transcription levels of genes involved in nitrogen (GS1 and GOGAT) and carbon (RCBL) metabolism, as well as water transport (TIP1.1). In conclusion, modern durum wheat lines differed in their response to water loss, the linear transpiration seemed to favor uptake and transport of water and nutrients, and photosynthetic metabolism led to higher grain yield except for very harsh drought conditions. The transpiration response to VPD may be a trait to further explore when selecting adaptation to specific water conditions.

Tolerance of Combined Drought and Heat Stress Is Associated With Transpiration Maintenance and Water Soluble Carbohydrates in Wheat Grains

“…The amount of water used in transpiration is driven by the evaporative demand in the atmosphere (Grantz, 1990). Our work illustrated the genetic variation in transpiration response to VPD previously observed in diverse wheat genotypes grown under well-watered and water-limited conditions (Schoppach and Sadok, 2012;Schoppach et al, 2016;Medina et al, 2019). In addition, we identified genetic variation in transpiration response to combined D&H ( Figure 5B).…”

Impact of Climate Variability and Its Related Disease Prevalence on the Yield of Winter Wheat (Triticum Aestivum Lam) in South East Ethiopia

“…However, the effect of rainfall variability on wheat production varies with types of varieties grown, types and properties of soils and climatic conditions of a given area [6]. Water deficits during grain filling not only reduce carbon assimilation rates, but increase canopy temperature via reduced transpiration rates and canopy senescence via accelerated leaf senescence [7]. Therefore, change in temperature and rainfall would change phonological requirements of future crops will, in fact, likely be the first factor to explore in explaining differences in yields [8].…”

Developing a sequential cropping capability in the JULESvn5.2 land–surface model

“…An additional simulation completed as a sensitivity test to see if low humidity in the driving data could be affecting the model yields, did have the effect of increasing NPP and yield for WestUP suggesting this hypothesis is worthy of further investigation. However, how plants respond to high VPD is still the source of a great deal of debate (Medina et al, 2019). There are two theories for the plant response to high VPD; the first is stomatal conductance decreases as VPD increases because of an increase in transpiration that lowers the leaf water potential (Streck, 2003;Ocheltree et al, 2014;Medina et al, 2019) rather than a direct response to the humidity.…”

“…However, how plants respond to high VPD is still the source of a great deal of debate (Medina et al, 2019). There are two theories for the plant response to high VPD; the first is stomatal conductance decreases as VPD increases because of an increase in transpiration that lowers the leaf water potential (Streck, 2003;Ocheltree et al, 2014;Medina et al, 2019) rather than a direct response to the humidity. In this first theory if the rate of movement of moisture out of the stomata cannot be met by the vascular structure of the plant then the plant will become water stressed (Streck, 2003).…”

“…However, Streck (2003) suggest that a direct response to VPD is probably contingent on the plant being exposed previously to water stressed conditions. (Medina et al, 2019) investigate the response to high VPD of both irrigated and rainfed C3 and C4 grasses and find evidence of the direct response to VPD in some species; in fact there are published results that support both of these hypotheses. Further investigation is needed to confirm exactly why the simulation at WestUP does not achieve the observed yields.…”