RESEARCH ARTICLE

PRELIMINARY STUDY ON THE PROPAGULE DEPENDENCY OF Rhizophora SEEDLINGS

Abstract

Early life of viviparous mangroves merely depends on the propagule and it can be assumed that the period and the degree of dependency could depend on the size and the intrinsic factors of the propagule as well as on the edaphic and environmental factors in which the seedlings are growing. However scientific studies on the propagule dependency of mangrove seedlings is poorly studied, irrespective to the fact that such information is vital particularly in mangrove restoration programs. However, propagule dependency of mangrove seedlings is poorly studied scientifically, irrespective to the fact that such information is vital particularly in mangrove restoration programs.

This study was carried out to investigate the growth performances of seedlings and the variations in the content of carbohydrate foods (starch content) in the propagule during the first 20 weeks period of the seedling growth of two viviparous species, Rhizophora apiculata and Rhizophora mucronata, which are having larger propagules and commonly used in replanting programs. The experiment was conducted, under three salinity regimes (i.e. 5psu; 15psu; 30psu) in a planthouse. A separate set of propagules was planted within the mangrove forest of Pambala lagoon under natural conditions and subjected to the same investigation as above.

Growth performances of both species grown under high salinity regime were significantly lower than those grown in low and moderate salinity regimes. Total leaf area of the seedlings of R. mucronata increased in higher order compared to that of the R. apiculata during the study period. After an initial drop in the content of starch in the propagules of both species, it started to increase slowly in the propagule of R. mucronata seedlings whilst the reduction was continued in R. apiculata propagules during the study period. However, the initial starch concentration of R. apiculata was remarkably higher than that of R. mucronata and hence, the starch content in R. apiculata, even after continued decreasing, was higher at the end of the study period. It can be hypothesized that the higher concentration of the stored food in smaller propagule of R. apiculate, compared to lower concentration of the stored food in propagules of R. mucronata, might lead to a similar longevity of viviparous mangrove seedlings of the two species allowing more or less the same chance to survive and establish in the same habitat as observed in many mangrove ecosystems.

Keywords: Mangroves, Restoration, Starch content, Propagule dependency, Rhizophora, Sri Lanka

How to Cite: Dissanayake,N.P,Madarasinghe,S.K,,,Kodikara ,K.A.S,Jayatissa,L.P,Perera,A.J.D,Koedam,N,Dahdouh-Guebas,F, (2014). PRELIMINARY STUDY ON THE PROPAGULE DEPENDENCY OF Rhizophora SEEDLINGS.WILDLANKA, 2(1):Pages 143-153

Published On:2014-12-31

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