Observations on vertical distribution of fungi associated with standing senescent Acanthus ilicifolius stems at Mai Po Mangrove, Hong Kong

Abstract

The present study was carried out to investigate the higher fungi colonizing the herbaceous mangrove associate Acanthus ilicifolius. This paper reports part of an investigation to determine if there is vertical distribution of fungi on the standing plant. The Mai Po Mangrove, Hong Kong is estuarine with great variations in salinity mainly due to the influence of the Pearl River. Senescent and dead stems of standing Acanthus ilicifolius were collected from mangroves in Mai Po from April to December 1992. The maximum tidal range observed was 2.6 m. A stratified sampling strategy was employed to assess the vertical distribution on the standing plant. A total of 44 fungi were collected: 32 Deuteromycotina, 11 Ascomycotina and 1 Basidiomycotina. Very frequent species were Acremonium sp.(55%), Colletotrichum gloeosporioides cf.(42.5%), Phoma sp. (42.5%) Fusarium sp.,(25%), Tubercularia sp. (24.2%) and Phialophora sp. cf. (19.2%). Agerita sp., Corynespora cassiicola, Stachybotrys chartarum, Trichoderma sp. and D82 were frequent, while the remaining species were recorded at less than 10%. Vertical zonation of fungi colonizing the standing stems was observed. The apical portions were colonized by typical terrestrial fungi and the basal portions by marine species. This can be attributed to both the nature of the substratum and the degree of exposure due to tidal inundation.