Salt Tolerance of &i&Xylocarpus mekongensis&/i& Pierre: Survival and Growth of Seedlings, Nutrients and Carbon Distribution in Seedling Parts

摘要

Xylocarpus mekongensis Pierre is the important tree species of the Sundarbans. The present study was conducted to evaluate the effect of salinity on the survival and growth of X. mekongensis seedlings. The distributional patterns of nitrogen, phosphorus, potassium, sodium, and carbon in seedling parts were also examined in relation to salinity. Comparatively higher survival (95%) of seedlings was observed at non-saline to slightly saline conditions (0-5 PSU) and it was decreased to 78% at 35 PSU salinity. The relative growth rate (RGR) was higher at non-saline to slightly saline (0 to 5 PSU) conditions compared to higher salinity. Nutrients, sodium, and carbon concentration are found to vary significantly (p < 0.05) among the parts of seedlings. Comparatively (p < 0.05) highest concentration of nitrogen (20 to 34 mg/g), phosphorus (0.50 to 0.75 mg/g), potassium (9 to 27 mg/g) and sodium (7 to 36 mg/g) were found in leaves, while the highest concentration of carbon (42% to 45%) was detected in the stem. However, nitrogen, potassium, and carbon concentration in different parts of seedlings showed significant (p < 0.05) negative correlations with salinity levels. It can be concluded that X. mekongensis has the capacity to tolerate higher saline condition but they grow well in non-saline to less saline conditions.