Genotype-dependent responses of chickpea to high temperature and moderately increased light.

Our aim was to understand how moderately increased light intensities influenced the response of chickpea to high temperature. Three chickpea genotypes (Acc#3, Acc#7 and Acc#8) were treated at control (26 °C and 300 μmol m s photosynthetic photon flux density/PPFD), high temperature (38 °C and 300 μmol m s PPFD), increased light intensity (26 °C and 600 μmol m s PPFD) and combination of increased light and temperature (38 °C and 600 μmol m s PPFD). The net photosynthetic rate (P) of Acc#3 and Acc#8 significantly decreased at high temperature regardless of light intensity. The P of all three genotypes at increased light intensity was significantly higher than that at high temperature. The intracellular CO concentration (C), stomatal conductance (g) and transpiration rate (E) of Acc#3 and Acc#8 at increased light intensity with or without high temperature significantly decreased in comparison with control and individually high temperature treatment. The relative water content of Acc#3 at high temperature and the combination treatment decreased as compared with control. The relative water content of Acc#7 at control was higher than the other three treatments. The F/F (Maximum quantum efficiency of photosystem II) of leaves from the three genotypes at 38 °C were lower than at 26 °C regardless of light intensity. The high temperature decreased chlorophyll content in the lower bottom leaf of Acc#7 and Acc#8 than control. In conclusion, chickpeas showed a higher net photosynthetic rate at increased light intensity to withstand heat stress, which was genotype-dependent. Physiological responses of different chickpea genotypes to increased temperature and light intensity indicated that distinct responsive mechanism of photosynthesis. This study provides information on how chickpea respond to high temperature and increased light intensity, which will help us to improve chickpea to deal with future climate changes.