TITLE:
Flowering and Fruiting Behavior, Seed Germination, and Survival Status of Heritiera fomes Buch-Ham and Excoecaria agallocha L. Species in the Sundarban Mangrove Forest of Bangladesh
AUTHORS:
Hasina Mariam, Abu Naim Mohammed Alamgir
KEYWORDS:
The Sundarban, Mangrove Forest, Flowering, Fruiting, Germination, Survival Rate
JOURNAL NAME:
Open Access Library Journal,
Vol.9 No.12,
December
22,
2022
ABSTRACT: Heritiera fomes Buch-Ham and Excoecaria agallocha L. are two major mangroves of the Sundarban mangrove forest. Among them, Heritiera fomes Buch-Ham is a less salt-tolerant species than E. agallocha, which is a salt-tolerant species but not extremely salt-tolerant. The flowering and fruiting behavior, seed germination, and seedling survival rate of Heritiera fomes Buch-Ham and Excoecaria agallocha L. were studied in three different saline zones viz. Oligohaline (Chandpai), Mesohaline (Jungra) and Polyhaline (Munshiganj). Fruiting periods of Heritiera fomes showed in March to June (pre monsoon) at both the Oligohaline (Chandpai) and Mesohaline (Jungra) zones, but at the Polyhaline zone (Munshiganj) showed late July to early August (monsoon to post monsoon) due to the high salinity needed for adequate moisture availability. The fruiting period of E. agallocha occurred from April to late July (dry to post monsoon) in the three saline zones. H. fomes and E. agallocha seed germination showed distinctive effects on salinity levels. The seeds of H. fomes showed a relatively higher rate of germination in both Oligohaline and Mesohaline zones (96%), while E. agallocha showed almost similar germination rates (88% - 90%) in all three saline zones. Seedling survival rates of both species were sharply reduced up to the age of 30 months. At this age, H. fomes showed a 25% survival rate at Oligohaline (Chandpai) and Mesohaline (Jungra) zones, but at the Polyhaline zone (Munshiganj) zone, it showed 10%. On the other hand, E. agallocha had a 15% survival rate in the Mesohaline (Jungra) and Polyhaline (Munshiganj) zones but only 13% in the Oligohaline (Chandpai).