Quantitative character variations of cambial derivatives in mangroves and their functional significance

Quantitative character variations of xylem cambial derivatives during secondary growth of the trunk are described for five representative mangrove species: Rhizophora stylosa (Rhizophoraceae), Bruguiera gymnorrhiza (Rhizophoraceae), Kandelia candel (Rhizophoraceae), Sonneratia alba (Sonneratiaceae) and Avicennia marina (Avicenniaceae). Two variation patterns in tracheary element length were revealed among these species. For R. stylosa, A. marina and S. alba, both vessel elements and fibers showed an increase in length during the early stages of secondary growth, then tended to be constant in later growth. In the other two species, little change occurred in the length of either vessel elements or fibers throughout the thickening growth period. Variation patterns in tracheary element length appeared to correspond with the different mangrove species' adaptations to their habitats. In addition, these five species exhibited diverse variation patterns in quantitative characters of the rays as well as in other quantitative characters of the vessels and fibers during secondary growth of their trunk.