Influences of the arbuscular mycorrhizal fungus Glomus mosseae on morphophysiological traits and biochemical compounds of common bean (Phaseolus vulgaris) under drought stress

Abstract

The symbiosis of arbuscular mycorrhizae (AM) with plant roots can enhance plant responses, especially to drought stress. An experiment was conducted in a growth chamber to examine the impacts of arbuscular mycorrhizae on improving the drought tolerance of common bean (Phaseolus vulgaris L.) subject to different drought level conditions (25%, 50% and 75% field capacity) and control (field capacity). The seeds were inoculated with Glomus mosseae and 10-day-old seedlings were subjected to the drought treatments. After nine weeks, the plants were harvested. The results indicated that root and shoot dry weight increased, whereas the root:shoot ratio decreased, in drought-treated AM plants. Furthermore, maximum root colonisation was observed at 75% field capacity. In the drought-treated AM plants, the phosphorus content of the root and shoot significantly increased, whereas the potassium content of the root declined compared with that of non-AM plants. Mycorrhizal plants showed higher CO₂ assimilation, water relative content, transpiration rate, superoxide dismutase, polyphenol oxidase and peroxidase activities, proline content, and leaf soluble proteins, as well as lower stomatal resistance, compared with the non-AM plants, especially in drought-stress conditions. In conclusion, common bean can benefit from the AM symbiosis.