DEVELOPMENT OF THE CONCHOCELIS STAGE OF PORPHYRA PERFORATA FROM THE TEMPERATE MEXICAN PACIFIC

Abstract

Salgado‐Rogel M. L2,3 & Zertuche‐González J. A.1 1Instituto de Investigaciones Oceanológicas UABC, Ensenada B.C. PO BOX 453 México 22860; 2Instituto Nacional de la Pesca, Centro Regional de Investigaciones Pesqueras, Ensenada, B.C. PO BOX 1306 México 22860. 3Facultad de Ciencias Marinas UABC, Ensenada B.C. PO BOX 453 México 22860.The conditions governing the reproduction of the conchocelis stage of Porphyra perforata were studied in vitro. Carpospores and conchocelis development were observed under a factorial of light and temperature with four levels of irradiance 15, 50, 100 and 275μEm‐2s‐1, with 8:16,12:12,16:8 photoperiods and four temperature levels 10,15, 20 y 25 °C. Conchocelis stage and conchosporangial structure developed without shells. Filaments were present at 10‐20°C and 15‐270μEm‐2s‐1 with 8:16, 12:12 ,16:8 photoperiods. The initiation of the conchosporangia was present at 50‐100μEm‐2s‐1. Release and germination of conchospores occurred only when the photoperiod changed from 8: 16 to 12:12. Filaments exposed to 270μEm‐2s‐1 (16:8) persisted with discolored apices that did not develop conchosporangia. Filaments not exposed to variations of photoperiod formed monospores. Our results are notoriously different from previous studies of P. perforata from Washington USA (cold region) were Conchocelis was vegetative at 15°C and 5‐100μEm‐2s‐1, and concho‐sporangial initiation was occurred at 10‐25μEm‐2s‐1 with a 8:16 photoperiod and only in shells as substrate. Differences were found between both regions in the levels of temperature, irradiance and photoperiod, which promoted the development of the reproductive structure of the Conchocelis stage. These results show that the conchocelis stage in plants from the temperate region develop and produce reproductive structures at higher light and temperature than plants from the cold region, which suggests ecophysiological differences of this species between both regions.