Response of C₄ (maize) and C₃ (sunflower) crop plants to drought stress and enhanced carbon dioxide concentration

Abstract

Sunflower (Helianthus annuus L.) and maize (Zea mays L.) were chosen as C<sub>3 </sub>and C<sub>4</sub> crop plants and assessed for the impact of enhanced CO<sub>2</sub> (700 ppm) and its interaction with drought stress in open top chambers (OTCs). The ameliorative effect of higher CO<sub>2</sub> concentration (eCO<sub>2</sub>) under drought stress was quantified. It is interesting to note that the C<sub>3</sub> crop responded significantly and positively with eCO<sub>2</sub> under both well-watered and drought stress treatments for root: shoot ratio while C<sub>4</sub> crop showed a better response only with the drought stress environment. Root volume showed a positive significant response with CO<sub>2</sub> concentration enhanced over ambient level and the increment in root volume was 146% and 340% in sunflower and maize crops, respectively. The leaf water potential, stomatal conductance and transpiration showed a decreasing trend in both the crops with drought stress and eCO2 showed an ameliorative effect leading to higher P<sub>n</sub> rates in sunflower crop under drought stress treatment. The findings reveal that improvement of root traits is worth attempting for the future crop behavioral responses under eCO<sub>2</sub> and drought stress environments. The study confirmed the beneficial effect of eCO<sub>2</sub> in maize and sunflower by ameliorating the adverse affects of drought stress.

Terrestrial net primary productivity in India during 1901–2010: contributions from multiple environmental changes

“…Several field scale studies have shown that elevated CO 2 concentration (600 ppm) stimulated plant biomass in grasslands (from 2.0 g plant −1 to 2.87 g plant −1 ), forests (Nataraja et al 1998), and croplands (Vanaja et al 2011). Using multivariate analysis, Bala et al (2013) reported that elevated CO 2 concentration was the most important factor in increasing total NPP in India during 1982-2006.…”

Effects of free‐air CO2 enrichment and drought on root growth of field grown maize and sorghum

“…Moreover, it was expected that the genotypes respond differently to this stimulation under the climate conditions of Central Europe, as sorghum is adapted to drought stress but not to cool climate and vice versa for maize. In addition, the effects of elevated [CO 2 ] and drought on SRL and RSR were investigated as the results published yet are highly uncertain (Grzesiak et al., ; Vanaja et al., ).…”

“…Changes in RDM under drought stress and elevated [CO 2 ] are likely to affect also root/shoot ratio (RSR). Results of current studies on RSR of maize under drought stress are ambiguous, showing higher, unchanged or lower RSR compared to well-watered conditions (Grzesiak et al, 1999;Vanaja et al, 2011). Rogers, Prior, Runion, and Mitchell (1995) reviewed the effects of elevated [CO 2 ] on RSR reporting differing responses.…”

Impact of elevated Carbon Dioxide on two groundnut genotypes (Arachis hypogaea L.) under Open Top Chamber facility

“…Higher increment in root volume than root length was observed by Vanaja et al in rainfed crops [10] under eCO2. Vanaja et al observed and reported that eCO2 significantly increased root volume in sunflower (C3) and maize (C4) crops [11]. The response of root dry weight to eCO2 was more significant at later growth stages in both the genotypes and the increment was higher in K-9 as compared with Dharani.…”