Comparative PSII photochemistry of quinoa and maize under mild to severe drought stress.

Quinoa has been identified as a climate-resilient crop that can overcome unfavorable conditions. This study explores the photochemical efficiency of quinoa compared to maize subjected to drought stress. The JIP-test was used to assess the photochemical efficiency of both crops. Proline content, leaf water potential, and membrane leakage were also determined. The maximum photochemical efficiency (F_v/F_m) did not change for quinoa and maize under moderate stress. However, severe drought conditions resulted in a decline in F_v/F_m in maize but not quinoa. Furthermore, the PSII performance index (PI_ABS,total) declined steadily in maize soon after the onset of drought stress. The decline in the PI_ABS,total values for quinoa was only observed after a period of severe drought stress. Membrane leakage was also more prevalent in the maize plants, while quinoa had higher proline contents. This study concluded that both quinoa and maize maintained PSII structure and function under moderate drought conditions. However, only quinoa maintained PSII structure and function under severe drought conditions.