Leaf morphological plasticity in Baen Avicennia officinalis (L.) among the salinity zones in the Sundarbans mangrove forests, Bangladeshs in the

In different saline zones, mangrove tree species show plasticity in their leaf morphological trails. However, leaf morphological plasticity in different salinity zone are not completely understood. The responses of Avicennia officinalis tree species in the Sundarbans to salinity zones were evaluated to better understand the mechanism of plasticity.  Avicennia officinalis is an exclusive evergreen mangrove species in the Sundarbans, Bangladesh. It prefers full sun light. Leaf sample were collected from three different saline zones and a total 17 parameters were measured and quantified. All collected data were analyzed using univariate and multivariate statistical tools to evaluate leaf morphological plasticity. This result showed a wide range of phenotypic plasticity of all leaf parameters studied in the Sundarban’s salinity zones. One-way ANOVA and Tukey’s posthoc test revealed significant differences (P< 0.05) in all leaf parameters among the salinity zones. This study confirmed that there was a high degree of phenotypic variation of Avicennia officinalis among the salinity zones of the Sundarbans. Leaf index (LI) and leaf thickness (LT) were maximum in strong saline zone than in moderate water zone or in fresh water zone. For all three saline zones of the Sundarbans, a plasticity index was developed for all of the parameters, and it was discovered that the plasticity index was highest in the strong saline zone for almost all of the parameters. The ordination plots (PCA) suggested clear morphological shift of the samples collected from different saline zones and showing relationship to salt stresses in natural environment. The result also provided clear evidence on plastic strategy of Avicennia officinalis against salinity zones in the Sundarbans. Therefore, leaf morphological plasticity could be used as a powerful biological signal of future climate change measures.

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