Growth, phenology and spore shedding in <i>Gracilaria arcuata</i> var. arcuata (Zanardini) Umamaheswara Rao and <i>G. corticata </i> var. <i>cylindrica</i> (J. Agardh) Umamaheshwara Rao (Rhodophyta)

Abstract

Maximum development of plants occurs in the intertidal region at Kilakarai, southeast coast of India, during March-April and January-February in <i>G. arcuata</i> var. <i>arcuata</i> and from November to February in <i>G.</i> <i>corticata</i> var. <i>cylindrica</i>. Tetrasporic plants are abundant almost throughout the year in both algae. Peak shedding of spores occurs during the maximum growth period in <i>G.</i> <i>arcuata</i> var. <i>arcuata</i> while seasonal variations are not observed in the discharge of spores in <i>G.</i> <i>corticata</i> var. <i>cylindrica</i>. Monthly output of tetraspores and carpospores varies from 43 to 28.291 and from 10 to 40.055 spores g^-1 fr wt in <i>G.</i> <i>arcuata</i> var. <i>arcuata</i> and <i>G.</i> <i>corticata</i> var. <i>cylindrica</i> respectively. There is no definite rhythm in diurnal output in these algae.