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Elucidation of "Isoyake" phenomenon: Study on allelochemicals of coralline red algae

阐明“Isoyake”现象：珊瑚红藻的化感化学研究

基本信息

批准号：
09660217
负责人：
SUZUKI Minoru
金额：
$ 2.11万
依托单位：
HOKKAIDO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1999
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09660217/
关键词：
Isoyake Coralline red alga Epiphytic diatom Sea urchin A1lelochemicals Kombu Glyceroglycolipid

项目摘要

As one of the causative agents of "Isoyake" phenomenon, we hypothesized that some allelochemicals produced by coralline red algae play an important role in maintaining Isoyake. In order to prove this, we investigated coralline algal metabolites which suppress growth of Laminaria algae, attract sea urchin larvae, induce larval settlement and metamorphosis in sea urchin, and stimulate feeding of sea urchins.Our results show that numerous sea urchins of Strongylocentrotus nudus continually inhabit coralline flats in Isoyake areas because coralline red alga, Lithophyllum yessoense, produces allelochemicals such as glycoglycerolipids that attract planktonic larvae of sea urchins, induce their settlement and metamorphosis, and stimulate feeding in juvenile and adult sea urchins. Therefore, sea urchins aggregate in large numbers at calm coralline flats and Isoyake is apparently maintained by destructive grazing of juvenile macralgae by them. On the other hand, at low seawater temperature herbivores, such as sea urchins, tend to reduce the grazing pressure toward macroalgae, including the kelp community. At low seawater temperature, temperate coralline red algae may slow down their growth and secondary metabolism. The reduced activity of secondary metabolism may lead to low production of allelochemicals that suppress the development and growth of Laminaria sporelings. Hence, Laminaria zoospores settling on coralline red algae may develop normally, leading to the recovery of kelp beds in coralline flats of Isoyake areas in the southwest coast of Hokkaido.

作为异物现象的诱因之一，我们推测珊瑚红藻产生的某些化感物质在维持异物过程中起着重要作用。为了证明这一点，我们研究了珊瑚藻类代谢产物，它们抑制海带藻类的生长，吸引海胆幼虫，诱导海胆幼体定居和变态，并刺激海胆的摄食。我们的结果表明，大量的裸球海胆继续栖息在等尾地区的珊瑚平原上，这是因为珊瑚红藻，石藻，产生糖甘油脂类等化感物质，吸引海胆的浮游幼虫，诱导它们的定居和变态，并刺激幼年和成年海胆的摄食。因此，海胆大量聚集在平静的珊瑚礁平原上，而等海胆显然是通过它们破坏性地捕食幼年巨藻而维持的。另一方面，在低海水温度下，食草动物，如海胆，往往会减少对大型藻类的捕食压力，包括海藻群落。在较低的海水温度下，温带珊瑚红藻的生长和次生代谢可能会减慢。次生代谢活性降低可能导致抑制海带幼苗发育和生长的化感物质产生减少。因此，附着在珊瑚红藻上的海带游动孢子可能会正常发育，导致北海道西南沿海等屋地区珊瑚滩的海带床恢复。