Effects of light, irrigation regimes and pericarp removal on grey mangrove seedling physiological characteristics

The production of seedlings with no stress is the first step in the nursery. Hence, the effects of pericarp removal, irrigation treatments, light, and their interaction on the physiological characteristics of grey mangrove seedlings were investigated in the nursery (Hormozgan province- Sirik Port). The aim of this study was to investigate the content of chlorophyll (a and b) and carotenoids in the leaves of grey mangrove seedlings using pericarp removal treatments (manual, fresh water, 50% seawater, 100% seawater), regular irrigations (twice a day, once a day, every other day, and every two days), and light intensities (100, 75, 50, 25, and zero percent). The analysis was performed using the GLM test. Based on the results, applying different treatments of pericarp removal, irrigation, and light treatments led to significant changes in physiological parameters (chlorophyll a, chlorophyll b, and carotenoids) (p<0.01). Removing the pericarp using fresh water and 50% seawater, irrigation regimes (twice a day and once a day), and light intensities (50 and 75%) caused the highest amount of chlorophyll content in seedlings. Furthermore, the highest amounts of carotenoids were observed in the 100% seawater treatment for pericarp removal, absence of light (0% light), and every two days irrigation treatment. In addition, the interaction effects (light × pericarp) indicated that carotenoids had the highest amount in the absence of light and pericarp removal using 100% seawater. Additionally, grey mangrove seedlings under moderate light, pericarp removal using 50% seawater, and once or twice a day irrigation treatments provide appropriate conditions for their activities. Therefore, it is recommended to use the above results in the production of grey mangrove seedlings in the nursery.