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This study aimed to determine the effect of elevation on survival and growth of mangrove seedlings during the establishment period. Seven typical mangrove species, Rhizophora mucronata Poir, R. apiculata Bl., Bruguiera cylindrica (L.) Bl., Ceriops tagal (Pirr.) C.B. Rob., Sonneratia alba J. Sm., Avicennia officinalis L. and Xylocarpus granatum Koenig were planted at various topographic sites in an intertidal zone of Phang Nga province, southern Thailand. These six bare areas included two that were abandoned after tin mining and four gap areas in natural habitats in June 1998. The experimental plots were on a slope and showed a maximal elevation difference of 1.8 m. The plots were naturally submerged with 2-3% saline water twice a day. Salinity, pH and the concentrations of several ions in the soil water were similar in all the plots. Survival and growth performance of seedlings were measured every 6 months. Many seedlings of B. cylindrica, C. tagal and X. granatum planted at lower elevations died with a year. R. mucronata and S. alba survived even at the lowest elevations, but showed changes in growth rate in response to topography. Thus, early growth of the seven mangrove species at different elevations differed and showed increasing tolerance to higher tidal inundations in the order: R. mucronata, S. alba, R. apiculata, A. officinalis, C. tagal, B. cylindrica and X. granatum. These findings provide guideline information for appropriate species selection in a mangrove rehabilitation program.

Morphological types of arbuscular mycorrhizal (AM) fungi in roots of understorey plants were examined in three different Japanese deciduous broadleaved forests. In total, 43 species belonging to 33 genera from 27 families were examined for the morphological types of AM. The number of flowering plant species having Paris-type AM was greater than those having Arum-type AM in each plot. This tendency was more prominent in herbaceous plants than woody plants with nine species having Paris-type associations among ten herbaceous plant species examined. Therefore, it is suggested from the ecological point of view that Paris-type associations could be advantageous for the herbaceous understorey plants growing slowly in these environments. The influence of plant identity on the morphological types of AM was also discussed by arranging the plants examined with the morphological types in a current plant phylogeny scheme. In this study, some new records on the morphological types of AM in some new plant families were obtained including the first report of a typical Arum-type AM in gymnosperms.