Primary Metabolite Profile Changes in Coffea spp. Promoted by Single and Combined Exposure to Drought and Elevated CO2 Concentration

Climate change scenarios pose major threats to many crops worldwide, including coffee. We explored the primary metabolite responses in two Coffea genotypes, C. canephora cv. Conilon Clone 153 and C. arabica cv. Icatu, grown at normal (aCO2) or elevated (eCO2) CO2 concentrations of 380 or 700 ppm, respectively, under well-watered (WW), moderate (MWD), or severe (SWD) water deficit conditions, in order to assess coffee responses to drought and how eCO2 can influence such responses. Primary metabolites were analyzed with a gas chromatography time-of-flight mass spectrometry metabolomics platform (GC-TOF-MS). A total of 48 primary metabolites were identified in both genotypes (23 amino acids and derivatives, 10 organic acids, 11 sugars, and 4 other metabolites), with differences recorded in both genotypes. Increased metabolite levels were observed in CL153 plants under single and combined conditions of aCO2 and drought (MWD and SWD), as opposed to the observed decreased levels under eCO2 in both drought conditions. In contrast, Icatu showed minor differences under MWD, and increased levels (especially amino acids) only under SWD at both CO2 concentration conditions, although with a tendency towards greater increases under eCO2. Altogether, CL153 demonstrated large impact under MWD, and seemed not to benefit from eCO2 in either MWD and SWD, in contrast with Icatu.

Sensitivity analysis of three pearl millet cultivars to varying temperature and CO2 concentration on summer pearl millet in south Saurashtra Agro-climatic zone of Gujarat using CERES-MILLET model

The sensitivity analysis of three cultivars (GHB 538, GHB 558 and GHB 732) of pearl millet was performed to study the impact of climate change on summer pearl millet in south Saurashtra Agroclimatic zone of Gujarat using calibrated CERES-millet model by changing maximum and minimum temperatures by -4 to +4 °C and increasing concentration of CO2 upto 530 ppm. Results revealed that with increase in maximum temperature by 4 °C, the grain yield was decreased by 11.4 to 19.9 % and anthesis and maturity was decreased by 10 to 13 days in different cultivars. The effect of minimum temperature was also of the similar order to maximum temperature, but the varietal differences were observed. The simulated grain yield increased up to 18.2 %, anthesis increased up to 11 days and maturity increased up to 17 days with elevated CO2 concentration of 530 ppm

Elevated Atmospheric CO2 Concentration Improved C4 Xero-Halophyte Kochia prostrata Physiological Performance under Saline Conditions

A significant increase in atmospheric CO2 concentration and associated climate aridization and soil salinity are factors affecting the growth, development, productivity, and stress responses of plants. In this study, the effect of ambient (400 ppm) and elevated (800 ppm) CO2 concentrations were evaluated on the C4 xero-halophyte Kochia prostrata treated with moderate salinity (200 mM NaCl) and polyethylene glycol (PEG)-induced osmotic stress. Our results indicated that plants grown at elevated CO2 concentration had different responses to osmotic stress and salinity. The synergistic effect of elevated CO2 and osmotic stress increased proline accumulation, but elevated CO2 did not mitigate the negative effects of osmotic stress on dark respiration intensity and photosystem II (PSII) efficiency. This indicates a stressful state, which is accompanied by a decrease in the efficiency of light reactions of photosynthesis and significant dissipative respiratory losses, thereby resulting in growth inhibition. Plants grown at elevated CO2 concentration and salinity showed high Na+ and proline contents, high water-use efficiency and time required to reach the maximum P700 oxidation level (PSI), and low dark respiration. Maintaining stable water balance, the efficient functioning of cyclic transport of PSI, and the reduction of dissipation costs contributed to an increase in dry shoot biomass (2-fold, compared with salinity at 400 ppm CO2). The obtained experimental data and PCA showed that elevated CO2 concentration improved the physiological parameters of K. prostrata under salinity.