Thermal stress-induced physiological and biochemical alterations in papaya genotypes

Abstract

Low-temperature stress significantly affects physiological processes inducing plant growth hindrance and reducing crop productivity. The present study aimed to understand the low-temperature stress-induced physio-chemical behaviour of five papaya genotypes such as Pusa Nanha, Red Lady, P-9-5, P-7-9 and one wild relative species Vasconcellea cundinamarcensis). Low-temperature stress significantly decreased the canopy gas exchange parameters, relative water content (RWC), membrane stability index (MSI) and chlorophyll content in all the papaya genotypes while tending to increase the total soluble sugars, proline and total soluble proteins, although the alterations were genotype-specific. V. cundinamarcensis showed greater tolerance to low-temperature stress, followed by P-9-5 and P-7-9, than other genotypes by maintaining the highest RWC, MSI, total soluble proteins, chlorophyll and proline contents. Our results showed that the chlorophyll content, membrane lipid peroxidation, and MSI could be used as the indices for screening potential papaya genotypes against cold tolerance.