条斑紫菜自由丝状体无性繁殖系快速培养及其养殖

本文报导了条斑紫菜(Porphyra yezoensis Ueda)自由丝状体快速培养并用固相化方法采苗下海养殖的试验。结果表明自由丝状体可以在较短的时间内快速生长发育成熟。用固相化方法采苗可以克服自由丝状体室内集中放散壳孢子困难的缺点。每网采200万枝壳孢子囊枝切段,其出苗情况、紫菜生长均达到生产要求。本试验为自由丝状体快速采苗应用于生产上提供了一条新途径。

Phototropism in the Marine Red Macroalga Pyropia yezoensis

Phototropism is a response to the direction of light that guides growth orientation and determines the shape of plants to optimize photosynthetic activity. The phototropic response is present not only in terrestrial plants but also in water-living algae. However, knowledge about phototropism in Bangiophycean seaweeds is limited. Here, we examined the phototropic response of the red alga Pyropia yezoensis to elucidate the regulatory mechanism of phototropism in Bangiophyceae. When leafy gametophytes and filamentous sporophytes of P. yezoensis were cultured under directional light, phototropism was observed in the gametophytes. Conchosporangia on the sporophytes also exhibited phototropism. Phototropism was positive in the majority of gametophytes and conchosporangia but in some cases was negative. In addition, a strong phototropic response occurred under white light, whereas blue and red light elicited minor and no responses, respectively. This observation is in contrast with the phototropic response in terrestrial plants and several algae, in which blue light is responsible for positive phototropism. Surprisingly, the genome of P. yezoensis has no homologues of the photoreceptors for blue and red light, revealing differences in the regulation of phototropism between terrestrial plants and P. yezoensis . Studies on the phototropism in P. yezoensis could shed light on the evolutional divergence of phototropic responses in plants.

外界因子对条斑紫菜自由壳孢子囊枝形成和生长影响

主要研究了不同光照周期(8L:16d、12L:12d和16L:8d)、不同温度(15℃、20℃和25℃)、不同光照强度(29、42、57、72和86μmol m-2.s-1)等外界因子对条斑紫菜自由丝状藻丝切断诱导形成壳孢子囊枝影响,以期获得条斑紫菜壳自由孢子囊枝形成的最佳外界条件。结果表明,在25℃和57μmol m-2·s-1条件培养30d后,短日照(8L:16d)对壳孢子囊枝诱导形成效果最好,其壳孢子囊枝形成率高达92.5%,50d后几乎达到100%;在25℃和短日照条件培养30d后,光照强度为57μmol m-2·s-1时,壳孢子囊枝诱导形成率达到最高(92.2%),光照强度过高过低均不利壳孢子囊枝形成;在57μmol m-2·s-1和短日照条件下,当温度为25℃时,壳孢子囊枝形成率最高,形成率随温度下降而减少。在12L:12d光照周期、57μmol m-2·s-1光照强度和25℃温度条件下,自由壳孢子囊枝生长最快,其日平均相对生长率可达54.43%。以上研究为实现紫菜细胞工程育苗新技术-自由壳孢子囊枝育苗奠定了坚实基础。