SEASONAL DYNAMICS IN THE LEAF CHLOROPHYLL CONTENT OF THE MAJOR MANGROVE SPECIES OF PICHAVARAM

Abstract

The present study aims to monitor the seasonal variability in the chlorophyll concentrations of eight major
mangrove species recorded from Pichavaram mangroves of Tamil Nadu. Along with the leaf pigment variation, the study also
concentrates on the prevailing soil conditions which are likely to affect the plant processes. Soil salinity, conductivity,
presence of major and minor elements was recorded. A study of the leaf pigments reveals that the highest values of total
chlorophyll (< 1) was observed during winter season for Bruguiera cylindrica, Excoecaria agallocha and Rhizophora
mucronata and the least observed was for Excoecaria agallocha and Lumnitzera racemosa for the summer season. The
Chlorophyll a/b ratio varied throughout the seasons. The ranges varied from 2.0-3.5 in summer to 1.0 -2.6 during post
monsoon (expect for Aegiceras corniculatum and Excoecaria agallocha, which possessed higher ratio greater than 6.0) and
typically around 1.0-2.0 (except Aegiceras corniculatum) for all the mangrove species under study. The highest carotenoid
content observed was for Avicennia officinalis during winter season (22.5 mg/g). Such studies on seasonal dynamics aids the
management, restoration and conservation practices of mangroves worldwide on a large scale. This provides a better aid to
ecological assessment activities too. Mangroves are majorly found along the coast lines of tropical and subtropical regions,
where the seasons are distinct and the climatic and environmental conditions are highly variable. Hence the leaf pigment
variability among the seasons highly affects the physiological processes like productivity. Thus the research could be o
greater aid to studies related to mangrove ecosystem functioning and productivity.