Occurrence of tension wood in two mangrove species and its effect on selected wood anatomical properties

The aim of the study is to characterise the cellular structures in tension wood and compare its effect on the selected anatomical parameters in two mangrove wood species viz. Excoecaria agallocha Linn. and Sonneratia caseolaris (L.) Engl. Wood blocks of 1 cm3 were prepared and thin sections of cross sections were cut using microtome and stained with Azure II to differentiate the structure of normal wood from tension wood fibres. The anatomical parameters analysed in this present study were vessel frequency, tangential vessel diameter and fibre wall thickness in tension wood as well as in normal wood. Vessel diameter and vessel frequency were significantly lower in tension wood compared to the normal wood in both the species. The reduction of tangential diameter in tension wood region is a way of protecting these elements from cavitation and providing mechanical support for the plant than liquid transport. A significant variation in fibre wall thickness was observed between tension wood and normal wood in both species.