A water-centred framework to assess the effects of salinity on the growth and yield of wheat and barley

Abstract

We used a water-centred framework (yield = transpiration × transpiration efficiency × harvest index) to investigate the effect of soil salinity on growth and yield of wheat and barley. Our working hypothesis is that salinity reduces transpiration proportionally more than transpiration efficiency. We established a glasshouse experiment with the factorial combination of four varieties (wheat: Janz, Krichauff; barley: Mundah, Keel) and three soil treatments: a control with no NaCl added, and NaCl added to achieve soil EC 1:5 0.75 dS m −1 and 1.5 dS m −1 . Pot-grown plants were watered to weight to determine transpiration and shoot dry matter was determined using a non-destructive image analysis system. Consistent with our hypothesis, salinity reduced transpiration (30-60%) proportionally more than transpiration efficiency (0-35%); transpiration accounted for 90% of the variation in shoot growth across varieties and treatments. Against this pattern, there were time-and variety-dependent responses. The rate of leaf appearance and the transpiration efficiency of Janz, Krichauff and Keel showed a two-stage response to salinity. In stage 1, salt-stressed plants maintained rate of leaf appearance and transpiration efficiency close to or slightly below those of the controls. After a clear break point where the slope changed, stage 2 was characterised by a substantial reduction in both traits. Stage 2 was not evident in saltstressed Mundah, which maintained a relatively high rate of leaf appearance and transpiration efficiency. Across species, harvest index increased from 0.40 in controls to 0.47 at 0.75 dS m −1 . Harvest index of plants grown at 1.5 dS m −1 was unaffected in wheat, and was reduced in barley. We propose that an understanding of the effect of salinity on crop development, growth and yield requires integration of low-level traits in a framework of resource capture, resource-use efficiency and plant allocation. Osmotic stress tolerance, Na + exclusion, and tissue tolerance to accumulated Na + would improve yield of salt-stressed crops to the extent that these traits contribute to the maintenance of water uptake and harvest index.

Salinity tolerance loci revealed in rice using high-throughput non-invasive phenotyping

“…2a,b). These results are consistent with a previous study of wheat and barley under saline conditions19. Notably, the aus panel had a greater average decrease for TR in all four intervals when compared with indica (Supplementary Table 1).…”

“…3). Salinity reduced TR proportionally more than TUE, similar to wheat and barley19. The indica panel had a lower average decrease in TUE compared with the aus panel (16.7% versus 24.4% for interval 2–6 days after treatment; Supplementary Table 1), and TUE was positively correlated with biomass production over time (RGR; Supplementary Fig.…”

Evaluating physiological responses of plants to salinity stress

“…Other physiological components are also likely to contribute to salinity tolerance, such as the maintenance of plant water status, transpiration (T) and transpiration use efficiency (TUE) (Harris et al , 2010; This et al , 2010; Barbieri et al , 2012); leaf area (Maggio et al , 2007); seed germination (Foolad and Lin, 1997); production of antioxidants (Ashraf, 2009); early seedling growth (Kingsbury and Epstein, 1984); and harvest index (HI) (Gholizadeh et al , 2014). Very little is known about these physiological components, so understanding the effects of salinity on these processes needs further investigation.…”

“…It has been proposed that the ability of plants to maintain normal rates of transpiration under saline conditions is an important indicator of salt tolerance, particularly because transpiration is related to normal rates of CO 2 uptake for photosynthesis (Harris et al , 2010). However, assessment of a plant’s transpiration rate using porometers (Meidner and Sheriff, 1976) and infra-red gas analysers (Nobel, 1991) can be difficult due to rapid changes in stomatal conductance that can occur in both space and time (Munns et al , 2006).…”

Simulation for response of crop yield to soil moisture and salinity with artificial neural network

“…An understanding of plant responses to water and salinity is of great practical significance. Recently, numerous studies have been carried out to investigate plant response to water and salt stress (Bassil and Kaffka, 2002;Katerji et al, 2003;Ashish et al, 2009;Chen et al, 2009;Clermont-Dauphina et al, 2010;Harris et al, 2010).…”