辽东半岛裙带菜室内常温全人工育苗：双高光控制、温度变化和配子体发育

Cultivation of Undaria pinnatifida in Liaodong peninsula: irradiance control, ambient temperature changes vs. gametogenesis in seedling production process

2010年,作者在辽东半岛成功进行了裙带菜室内常温全人工育苗大规模生产试验,并全程进行了光照强度、温度和配子体发育相关性的研究。研究表明,采用双高光期(≥50μmolphotons/m2·s)调控配子体的生长和发育可达到理想效果。从采苗至度夏前,采用高光照使配子体充分完成营养生长;从度夏结束至幼苗出库前,同样采用高光照,使配子体快速发育形成孢子体并迅速生长。现场观察表明,只要光照强度逾越了诱导发育的阈值,裙带菜配子体在24℃仍然能够正常发育并形成孢子体;幼孢子体能够耐受24～26℃的高温,但是最适生长温度为20～22℃;孢子体越小,耐受高温能力越强。在24～26℃的高温条件下,幼孢子体生长缓慢,较大个体会出现尖端溃烂缺失的现象。在整个育苗过程中,根据温度变化和配子体的显微观察结果因地制宜地对光线进行实时调整。出库前培育的苗帘在幼苗密度、大小和健康方面均达到商业化栽培的要求。

Undaria pinnatifida is a commercially important seaweed in China with a more than 30 years of farming history. However, artificial seedling production of this seaweed has not yet been stable. How to control the light intensity according to seasonal changes of temperature is the key to the success of artificial seedling production in practice. In this investigation, we report our large-scale indoor artificial production of seedlings by use of spores at room temperature in Liaodong peninsula, the major farming area of U. pinnatifica in China, mainly on how to control irradiance levels during the 3-month period. According to the requirements of the gametogenesis resulted from our previous studies, we adopted two high irradiance phases （≥50 μmol photons/m^2 · s） at the beginning and the ending stage. The first high light phase started from seeding of zoospores and ended at the beginning of over-summering phase. This period allowed a full growth of male and female gametophytes. The second high light phase, starting from the end of the over-summering period to the end of the seedling production, allowed a rapid gametogenesis and formation of sporophytes. Under suitable irradiance the gametophytes were able to complete gametogenesis and produce normal young sporophytes even at temperature as high as 24 ℃. The optimal temperature for the growth of young sporophytes was 20- 22 ℃. 2-5 mm sporophytes could temporarily tolerate 24-26 ℃, however, the smaller they were, the higher the capacity they demonstrated in tolerating higher temperature. Real-time manipulation of irradiance according to the temperature changes and the development of gameto- phytes over a period of 3 months generated very good results of seedlings on strings in 2010. This investigation will shed light on improvement of techniques in terms of seedling production in this region.