Effect of temperature on the development of Saccharina japonica gametophytes

Abstract

Spores (collected at 10 ± 1 °C, 2 h after releasing) and young gametophytes (newly generated from spores cultured at 10 ± 1 °C for 8 days) of Saccharina japonica were first cultured at 15 ± 1, 19 ± 1, and 23 ± 1 °C for various times (2, 5, and 8 days) and then at 10 ± 1 °C (culturing patterns S and G, respectively). Spores were also cultured at a constant of 10 ± 1 °C (pattern C) and used as the control. The length and percentage of young gametophytes, size and percentage of gametophytes, and ratio of female to male gametophytes were measured in order to determine the effect of temperature on the development of gametophytes. Temperature and exposure time of spores and young gametophytes at the first culturing temperature significantly affected the development of gametophytes as were indicated by all biological parameters except the ratio of female to male gametophytes. The spores were more sensitive to temperature than young gametophytes. Gametophytes developed from the spores that survived temperature stress can recover their growth. High temperature selection at the early developmental stages of gametophytes was effective for screening gametophytes applicable for breeding high temperature-resistant varieties and hybrids.