Reproductive biology ofStictosiphonia hookeri(Rhodomelaceae, Rhodophyta) from Argentina, Chile, South Africa and Australia in laboratory culture
✍ Scribed by John A. West; Giuseppe C. Zuccarello; Ulf Karsten
- Publisher
- Springer
- Year
- 1996
- Tongue
- English
- Weight
- 509 KB
- Volume
- 326-327
- Category
- Article
- ISSN
- 1573-5141
No coin nor oath required. For personal study only.
✦ Synopsis
The red alga Stictosiphonia hookeri is epilithic in shaded habitats of the upper intertidal zone from 30 to 55° S . Thalli of this species from Argentina, Chile, South Africa and Australia, usually without reproductive structures when collected, all developed tetrasporangia in culture . Although good vegetative growth occurred in all nine isolates at 20-25 °C, 12 :12 light : dark cycle, 10-30 ttmol photons m -2 s -I , none reproduced in these conditions except one isolate from Australia . At 15 °C the four South African (34° S) isolates developed tetrasporangial stichidia, and three completed a Polysiphonia-type life history . Gametophytes were unisexual or bisexual . At 15 °C one isolate from Chile (36°S) formed tetrasporangia, but sporelings were not viable . At 10 °C isolates from Argentina and Chile (53° S and 54° S) formed tetrasporangia ; however, only the Chile isolate completed a Polysiphonia-type life history with unisexual gametophytes . The temperature required to induce sporogenesis correlates with the range of water and air temperatures in the natural habitats of each isolate . In irradiances >50 µmol m-2 s-I the thalli became yellow-brown within two weeks because of phycobiliprotein loss, but this did not impair growth or reproduction . The Argentina and Chile isolates were resistant to freezing in seawater for at least two days, showing no cell damage . The protein cuticle of the outer cell wall is repeatedly shed in culture . This may serve to minimize the attachment of epiphytes in the field .