Investigating the process of changes in vegetative characteristics of grey mangrove seedlings (Avicennia marina Forssk. Vierh) over time and leaf chlorophyll content in different concentrations of desalination sewage

The aim of this study was to investigate changes process of vegetative characteristics of mangrove seedlings over time and determination of chlorophyll content in different concentrations of desalination sewage. After collecting propagules from 30 healthy mother trees and planting them, propagules were irrigated with water treatments of 0, 1, 2, 3, 5, 10 and 20% concentration of desalination sewage. Then vegetative characteristics of seedlings were measured every two weeks in different treatments and analyzed using repeated measure model. The amount of chlorophyll a and b were measured by Arnon method and compared using ANOVA. The results showed that changes in height growth, length and radial growth of leaf of mangrove seedlings had significant differences over time. Gradient of height growth and length growth of leaf was sharp at the beginning and then trend increased gradually. Radial leaf growth was slowly increasing with increasing time and was almost zero at the end of the period. The average of height growth, length and radial growth of leaf decreased at high amount of concentration of desalination sewage. The amount of chlorophyll a (5.37mg/g), b (1.30 mg/g) and total chlorophyll (6.67 mg/g) were the highest in the 0% treatment. According to the results, growth slows down over time with increasing age, and at high concentrations, this decline becomes more intense. Therefore, it was recommended that suitable management programs should be used in using of desalination set and sewage removing in order to minimize mangrove forest damages.