Effects of CO₂ Enrichment and Drought on Photosynthesis, Growth and Yield of an Old and a Modern Barley Cultivar

Abstract

Susceptibility of crops to drought may change under atmospheric CO 2 enrichment. We tested the effects of CO 2 enrichment and drought on the older malting barley cultivar Golden Promise (GP) and the recent variety Bambina (BA). Hypothesizing that CO 2 enrichment mitigates the adverse effects of drought and that GP shows a stronger response to CO 2 enrichment than BA, plants of both cultivars were grown in climate chambers. Optimal and reduced watering levels and two CO 2 concentrations (380 and 550 ppm) were used to investigate photosynthetic parameters, growth and yield. In contrast to expectations, CO 2 increased total plant biomass by 34 % in the modern cultivar while the growth stimulation was not significant in GP. As a reaction to drought, BA showed reduced biomass under elevated CO 2 , which was not seen in GP. Grain yield and harvest index (HI) were negatively influenced by drought and increased by CO 2 enrichment. BA formed higher grain yield and had higher water-use efficiency of grain yield and HI compared to GP. CO 2 fertilization compensated for the negative effect of drought on grain yield and HI, especially in GP. Stomatal conductance proved to be the gas exchange parameter most sensitive to drought. Photosynthetic rate of BA showed more pronounced reaction to drought compared to GP. Overall, BA turned out to respond more intense to changes in water supply and CO 2 enrichment than the older GP.

Simulated annual changes in plant functional types and their responses to climate change on the northern Tibetan Plateau

“…In terms of the CO 2 fertilization effect, Kimball (1983), Chang et al (2016), Kim et al (2016) and Schmid et al (2016) stated that as CO 2 level increased, vegetation yield changed, and the change was however related to the environment conditions such as light, soil nutrient and soil moisture and temperature. We assume that the CO 2 fertilization effects can be reflected from the changes in photosynthesis and net primary productivity.…”

Atmospheric CO2 enrichment and drought stress modify root exudation of barley

“…Results of these measurements are given in Schmid et al . (). Plant development was reported using the BBCH code (Meier, ).…”

“…Schmid et al . () have investigated growth, yield, and photosynthetic parameters in the same experiment as ours with barley and found that CO 2 fertilization compensated for the negative effect of drought on grain yield and water‐use efficiency, especially in one of the two cultivars tested. Here, we present results from root exudation analyses to gain information on responses of the hidden half of barley plants.…”

CO2-Induced Changes in Wheat Grain Composition: Meta-Analysis and Response Functions

“…Photosynthesis and growth in C3 plants are often enhanced by eCO 2 resulting in a higher yield, which has been observed for many crops [2]. The magnitude of yield response has been shown to vary between different crops [3] and crop varieties [4,5], but also to depend on differences in experimental systems [6]. It has been argued that yield stimulation is overestimated due to unrealistic growing conditions in enclosure systems, including open-top chambers (OTCs) [7,8].…”