Seasonal cambial activity of some mangrove trees in Inner Gulf of Thailand in dependence on climate

Abstract

This study aims to investigate the relationship between the cambial activity of Rhizophora mucronata, Avicennia alba, and Avicennia marina and climatic factors (e.g., rainfall, temperature, salinity, and sea water level) in Samut Sakhon Province, Thailand. Cambial samples were collected once a month from January to December 2009, resulting in total of 18 samples from 9 trees in every month. The samples were prepared by the epoxy technique. The cambial activity was investigated by counting undifferentiated cells in the cambial zone. The relationship between cambial activity and climatic factors were investigated by Pearson's correlation. Correlations among the cambial activity of the thr ee species with rainfall, temperature,and salinity were weak and statistically insignificant. The strongest and most statistically significant relationships were observed with sea water level of R. mucronata (r =-0.67, p < 0.01) and A. alba (r =-0.52, p < 0.05). Therefore, cambial activity of the three species is not driven by seasonal climatic factors. For A. alba and A. marina, more than one cambium was found to be simultaneously active.