Get access

TWO SPECIFIC CAUSES OF CELL MORTALITY IN FREEZE-THAW CYCLE OF YOUNG THALLI OF PORPHYRA YEZOENSIS (BANGIALES, RHODOPHYTA)

Authors

  • A Peng Lin,

    1. Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, 266071 Qingdao, China
      Graduate School, Chinese Academy of Sciences, 100049 Beijing, China
    Search for more papers by this author
  • Guang Ce Wang,

    Corresponding author
    1. Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, 266071 Qingdao, China
      Author for correspondence: e-mail gcwang@ms.qdio.ac.cn.
    Search for more papers by this author
  • Song Dong Shen,

    1. Department of Cell Biology, Medical College of Soochow University, 215123 Suzhou, China
    Search for more papers by this author
  • Fang Yang,

    1. College of Marine Science' and Engineering, Tianjin University of Science & Technology, 300457 Tianjin, China
    Search for more papers by this author
  • Guang Hua Pan

    1. College of Marine Science' and Engineering, Tianjin University of Science & Technology, 300457 Tianjin, China
    Search for more papers by this author

  • Received 2 August 2009. Accepted 28 January 2010.

Author for correspondence: e-mail gcwang@ms.qdio.ac.cn.

Abstract

Porphyra yezoensis Ueda is an important marine aquaculture crop with single-layered gametophytic thalli. In this work, the influences of thallus dehydration level, cold-preservation (freezing) time, and thawing temperature on the photosynthetic recovery of young P. yezoensis thalli were investigated employing an imaging pulse-amplitude-modulation (PAM) fluorometer. The results showed that after 40 d of frozen storage when performing thallus thawing under 10°C, the water content of the thalli showed obvious effects on the photosynthetic recovery of the frozen thalli. The thalli with absolute water content (AWC) of 10%–40% manifested obvious superiority compared to the thalli with other AWCs, while the thalli thawed at 20°C showed very high survival rate (93.10%) and no obvious correlation between thallus AWCs and thallus viabilities. These results indicated that inappropriate thallus water content contributed to the cell damage during the freeze-thaw cycle and that proper thawing temperature is very crucial. Therefore, AWC between 10% and 40% is the suitable thallus water content range for frozen storage, and the thawing process should be as short as possible. However, it is also shown that for short-term cold storage the Porphyra thallus water content also showed no obvious effect on the photosynthetic recovery of the thalli, and the survival rate was extremely high (100%). These results indicated that freezing time is also a paramount contributor of the cell damage during the freeze-thaw cycle. Therefore, the frozen nets should be used as soon as time permits.

Get access to the full text of this article

Ancillary