海带配子体高温耐受性评价指标体系构建及其应用OA

Saccharina japonica is an economically important alga in China,which was originally derived from wild populations in Japan.Owing to the environmental temperatures in the Chinese cultivation sites being higher than those in its native habitat,heat tolerance is recognized as an important breeding objective for the development of superior kelp varieties.However,a precise evaluation system for high-temperature tolerance traits in kelp is lacking,along with systematic and comparisons across varieties and strains.This study evaluated 100 kelp gametophyte samples from different years and regions,using growth and photosynthetic indicators to establish a high-temperature tolerance evaluation index and identify high-temperature-tolerant gametophytes. By integrating relative growth rate and chlorophyll fluorescence parameters,the heat tolerance of kelp gametophytes spanning more than 40 years was evaluated and compared across multiple dimensions.After high-temperature stress,kelp gametophytes from the most recent 20s exhibited the highest relative growth rate,and minimal decline,likely due to the long-term exposure to warmer cultivation environments.In contrast,1980s gametophytes exhibited the greatest reduction in photosynthetic possibly due to prolonged storage under low-temperature,low-light conditions,,making them more sensitive to heat stress.In recent years,the rapid increase in temperature and the pursuit of higher production yields may have contributed to the enhanced heat tolerance observed in kelp gametophyte growth during the 2020s.However,changes in photosynthetic capacity may require longer periods of acclimation and accumulation.Overall,from the 1980s to the 2020s,the heat tolerance of kelp gametophytes gradually increased.In summary,this study developed an evaluation model for high-temperature tolerance in kelp gametophytes To the best of our knowledge,this is the first systematic evaluation and comparison of heat tolerance among kelp varieties and strains in China over the past 40 years.This collection of superior high-temperature-tolerant germplasm materials that was obtained is of great significance for kelp germplasm innovation and the breeding of superior varieties.