Effect of salinity on the physiological and biochemical responses of neem

Abstract— The present study was conducted to evaluate the plant growth, physiological and biochemical changes of neem under different salinity levels (4, 8, 10 and 12 dS/m) which have multipurpose use in agroforestry. Growth parameters, photosynthetic pigments, carbohydrate, proline and total phenol were investigated 30, 60, 90 and 120 days after treatment imposition. The results revealed that salinity caused significant differences in all the growth parameters and the maximum reduction were observed when plants were exposed to high salinity (12 dS/m) level and minimum were in control treatments. It was found that total dry matter and relative water content were reduced 72% and 40% in 12 dS/m compared to control plants at 120 DATI, respectively. By increasing saliniy 0 to 12 dS/m, the chlorophyll (the photosynthetic pigment) and carbohydrate (the photosynthetic product) content decreased, but increased the level of proline (an amino acid) and total phenol content (an antioxidant) in different days. The highest accumulation of free proline and total phenol content was recorded in 10 dS/m treatment and it was 77% and 59% greater than control plant, respectively. These findings suggest that though growth and biochemical parameters of neem were affected by salt stress, but all the plants survived in different salinity levels. Among all different salinity levels, neem can performed better up to 10 dS/m salinity level could be due to better antioxidant system of neem to cope up with oxidative damage to stressed plants.