Abstract

Parthenogenesis, the development of female gametes without fertilization, is relatively common in brown algae, although limited quantitative information on the phenomenon is available. Its occurrence is reported for the first time in Lessonia nigrescens Bory, a member of the Laminariales and a key ecological component of the benthic algal communities along the Chilean coast. Isolated female gametophytes developed into parthenosporophytes throughout the year, with a maximum in spring to early summer. Isolated male gametophytes, on the other hand, never developed fronds. Parthenosporophytes obtained in the laboratory developed normally when cultivated under greenhouse conditions, and the resulting individuals were indistinguishable in size, shape, texture, and color from heterozygous sporophytes. Quantification of DNA of various tissues demonstrated that early during their development, parthenosporophytes duplicated their DNA content, displaying levels similar to heterozygous sporophytes and almost twice the level found in gametophytes. One out of 45 individuals from a field population yielded only female gametophytes, strongly suggesting that parthenogenesis does occur in wild stands of L. nigrescens. © 2007 Phycological Society of America.