Influence of arbuscular mycorrhizal fungi on the growth and physiology of Annona muricata (L.) under two irrigation levels under greenhouse conditions

Drought adversely affects crop growth and productivity by reducing photosynthetic rates and damaging photosynthetic machinery. This study investigates the protective role of arbuscular mycorrhizal fungi (AMF) on Annona muricata plants under drought conditions. Specifically, we evaluated the effects of two AMF species (Rhizophagus intraradices and Funneliformis mosseae) and two mycorrhizal consortia (Agua Dulce and Cerro del Metate) on the growth and fluorescence variables of Mexican A. muricata cultivars under both limited and normal irrigation. The Cerro del Metate consortium and F. mosseae significantly enhanced A. muricata growth under limited irrigation, improving plant height, stem diameter, and leaf number by 43 %, 46 %, and 120 %, respectively, compared to the controls (P <= 0.05). Additionally, R. intraradices improved the maximum performance of photosystem II (FvP/FmP) under both irrigation conditions, achieving values of 0.76 versus 0.70 in the control under normal irrigation (P <= 0.05). Similarly, under limited irrigation, treatments with R. intraradices showed a value of 0.76 compared to 0.74 in the control (P <= 0.05). These findings suggest that R. intraradices reduces damage to photosystem II. It is concluded that mycorrhized and non-mycorrhized plants showed different chlorophyll fluorescence profiles, reflecting the state of the photosynthetic apparatus. This indicates that mycorrhized plants undergo modifications in primary photochemistry, likely due to the protective effects under water-limited conditions.