Physiological and Biochemical Responses of Cowpea to Elevated Temperature

Abstract

Aims: To evaluate physiological, biochemical, and micrometeorological responses of cowpea (Vigna unguiculata L. Walp.) var. CO 7 to a +2 °C temperature regime and to compare six organic and inorganic treatments. Study Design: The experiment used a factorial completely randomised design with six treatments under two temperature regimes (ambient and ambient +2 °C), with three pot replicates for each treatment within each regime. Place and Duration of Study: The experiment was conducted during April-June 2021 in a Temperature Gradient Tunnel at the Agro Climate Research Centre, Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu, India. Methodology: Physiological, biochemical, and micrometeorological traits were evaluated at 30, 45, and 60 days after sowing. The measured variables were proline content, peroxidase activity, cell membrane thermostability, chlorophyll index, photosynthetic rate, stomatal conductance, transpiration rate, and leaf temperature. Results: Relative to ambient conditions, the +2 °C regime was associated with higher proline content, peroxidase activity, transpiration rate, and leaf temperature and with lower cell membrane thermostability, chlorophyll index, photosynthetic rate, and stomatal conductance. Across sampling intervals, vermicompost combined with a 3% Panchagavya foliar spray (T2) generally showed the most favourable overall physiological profile among the tested treatments. Conclusion: Under the conditions of this pot experiment, vermicompost combined with 3% Panchagavya was associated with improved physiological and biochemical performance of cowpea exposed to moderate warming. Field and multi-season validation is needed before effects on yield or long-term crop productivity can be inferred.