Photosynthetic apparatus of soybean exposed to drought due to application of arbuscular mycorrhiza

Abstract

Background and Objective: Water shortage is a common condition in most rainfed area in the tropics especially when irrigation is limited. Response of plants to water shortage is related to physiological, biochemical and morphological adjustments. A study aimed to investigate the changes in physiological behaviour of drought stressed soybean plants applied with arbuscular mycorrhizal fungi. Materials and Methods: The study was conducted at the Screen House Faculty of Agriculture, University of Hasanuddin in Makassar, Indonesia. Three water supply levels were used consisted of 80-90, 60-70 and 40-50% of field capacity and four dosages of mycorrhizal fungi were applied consisted of 4 levels, control, inoculation of mycorrhizal fungi 0.05, 0.10 and 0.15 g/pot, respectively. Data were analyzed using a factorial ANOVA and least significance difference (LSD) test. In addition, a correlation analysis was performed to observe the relationship between parameters. Results: Results showed that drought decreased photosynthetic capability of soybean in terms of leaf chlorophyll index, the rate of light intensity acceptance and the percentage of energy absorption. In addition, stomatal density also declined in the stressed plants when water supply was limited to 40-50% of field capacity. However, application of the fungi as much as 0.15 g/pot in the stressed plant can retard the decline of leaf stomatal density. Conclusion: Hence, it can be concluded that application of mycorrhiza fungi improve photosynthetic capability of soybean experiencing drought stress.