Effect of exogenous addition of proline on the growth and chemical compositions of Inga edulis Mart. seedlings under salinity conditions

Abstract

The present experiment was conducted during two seasons of 2020 and 2021 at Al- Marashda Agricultural Research Qena, Egypt. It was intended to determine the effect of exogenous proline addition on the vegetative growth and chemical compositions of Inga edulis seedlings grown under salt stress conditions. Seedlings were treated with proline at 100 and 200 ppm as a foliar spray either with or without salinity at 2000, 4000 and 6000 NaCl + CaCl 2 . In both seasons, different plant growth stem and root length, fresh and parameters and chemical compositions were significantly affected by proline and salinity with or without proline. However, seedlings sprayed with proline often had greater growth parameters as dry weight of stem and roots as well as a number of leaves than those of other treatments. Also, the highest values of nitrogen, phosphorus, potassium, chlorophyll a & b contents were noticed with proline treatments. The addition of proline at 100 and 200 ppm with 2000 ppm salinity produced vigor seedlings compared to the control. Meanwhile, the addition proline with salinity at 4000 or 6000 ppm did not exhibit a pronounced effect on the growth and chemical compositions compared to the control in both seasons. Seedling vigor and its chemical composition was reduced in response to salt stress without proline addition, while proline content in leaves was raised. These findings suggest that addition proline treatments can ameliorate the negative effects of salinity as NaCl + CaCl 2 on the growth and chemical compositions of Inga edulis seedlings.