The carpospore culture of industrially important red alga Gracilaria dura (Gracilariales, Rhodophyta)

Gracilaria dura occurring in Indian waters has been reported to be potential sources of agarose (US Patent 2005/0267296A1). The scanty biomass and restricted occurrence at the bottom of deep tide pools along few locations of the northwestern coast of India limited its exploitation for industrial utilization. The paper describes carpospore output, their viability and early stages of development in the laboratory as well as out-planting and field cultivation of tetrasporophytic plants of G. dura. The maximum spore liberation took place on day four with output of 808 (+/- 22) per cystocarp. The percentage spore viability ranged from 22 to 36% (r(2)=0.1008, n=30) at the end of first week and 17-27% (r(2)=0.0011, n=30) at the second week of carpospores culture. The spores underwent germination immediately without any resting period and followed the Dumontia type developmental pattern. The erect thallus developed from the multicellular basal disc. After 6 months under laboratory culture, the erect cylindrical thallus attained the minimum size of field transplantation with about 3-4 cm frond length. The out-planting of laboratory-grown tetrasporophytes showed fast adaptation to the sea with satisfactory average growth rate of 4.67% d(-1). The present investigation has demonstrated the possibility of field cultivation of this species using carpospores under the realistic culture conditions. The scaling up of this method could result into commercial farming of this industrially important red alga. (c) 2009 Elsevier B.V. All rights reserved.