studies on the brown alga dictyopteris longifolia (Dictyotales), with special reference to the effects of wave action

Abstract

Aspects of the brown alga Pict~'ppt;eris lQ..n..qifolia at. Palm Beach, Natal, were investigated wi\'-;.hspecial reference to the effect of wave expozu~e~ A description of the species is giv~n and the nomencluture discussed. D~strib1i.ltion of n. ).or~gifolia was det~rmimad from literature and herbarium speof.mens . various r(\~:~thodosf measuring wave exposure were assessed and review~~d. At'!;:.emptswere made to quantify sand abrasion and deposition in tihe scudy si.tes. Morphological and structural aspect;s of the cha LLus were found to vary considerably with season and wave exposure" Light and scanning electron microscopy studie.s indicated the relatjvely complex cell organisation of this brown alga. The prolific regeneration from various thallus sections of .Q. longifolia indicate that regenerat.ion is an important survival strate 'JY following damage. Sexual reproduction and tetrasporogenesis were investigated. Sex.ual reproduction was not prolific in the field, however, tetraspores were abundant and are believed to be particul~rly importcmt in high wave exposure areas. 11. _j.Q.ngi;f'clige,x_periences a range of environmental conditions and responds to these with morphological, structural and reproductive &daptations.