Impact of high-temperature stress on anatomical adaptations in mungbean genotypes

Rising global temperatures present a major challenge to summer-season legumes like mungbean, affecting their growth and productivity. Understanding plant anatomical adaptations under high-temperature stress (HTS) is crucial for developing heat-resilient crop varieties. This study aimed to assess the anatomical modifications in three mungbean(Vigna radiata (L.) Wilczek) genotypes (MH 421, MH 1772, and IPM 312-19) under different sowing conditions. The experiment was conducted in a randomized block design (RBD) under field conditions, comparing normal-sown (March, <40°C) and late-sown (April, >40°C) crops. Root and stem transverse sections (T.S.) were analyzed to examine variations in xylem vessel characteristics. Results revealed a significant increase in xylem vessel size, thickness, and number under late-sown conditions, indicating structural modifications to cope with heat stress. IPM 312-19 exhibited the highest increase in vessel diameter, with a 32.8% expansion in root T.S. and 38.90% in stem T.S. compared to normal-sown plants. These anatomical changes suggest improved water transport efficiency and turgor maintenance under HTS. This study provides novel insights into xylem plasticity in mungbean, contributing to a better understanding of legume heat adaptation mechanisms. The findings can aid in breeding and selecting heat-tolerant mungbean genotypes, ensuring sustainable yields under rising temperatures.