LEAF PIGMENT AND TOTAL CARBOHYDRATE CONTENT AT EARLY STAGES OF HERITIERA FOMES BUCH. SEEDLINGS GROWN AT THREE SALINE ZONES OF THE SUNDARBANS, BANGLADESH

Abstract

The experiment was conducted to find the leaf pigments and carbohydrate content in Heritiera fomes at different growth stages exposed to different salinity levels in the Sundarbans areas, Bangladesh. Three leaf pigments, viz., chlorophyll a, chlorophyll b, and carotenoid, total chlorophyll, and total carbohydrate content of Heritiera fomes Buch. Ham seedlings were determined in the leaves grown in the oligohaline, mesohaline, and polyhalite zones at early (6 and 9 months) and survival ages (30 months) following standard methods. Leaves from seedlings at the age of 30 months (survival aged) show relatively high leaf pigments than that of the 6 and 9-month-old seedlings grown in the three saline zones. Total chlorophyll content in leaves was found low in the oligohaline zone at the early and survival ages, but higher in the polyhalite zone at the early ages, and higher in the mesohaline zone at the survival age. Chlorophyll b was relatively higher than chlorophyll a. Leaves of 30 months seedlings showed relatively higher chlorophyll a than chlorophyll b at the polyhalite zone, but higher chlorophyll b was noted at the mesohaline zone. The highest content of total carbohydrates was observed in the shoots of 6, 9, and 30 months ages H. fomes seedlings in the polyhalite zone, while the lowest was in the mesohaline zone. At the same age periods in the mesohaline zone, the roots of the H. fomes seedlings showed relatively higher carbohydrate content and lower at the 30 months seedlings in the all saline zones. Chlorophyll a was found to be more sensitive than chlorophyll b and carotenoid at different salinity levels tested. Higher carbohydrate content was discovered as an additional mechanism to prevent salt toxicity at early ages of high saline conditions (polyline zone).