DYNAMICS OF A PECULIAR PLANT HERBIVORE RELATIONSHIP - THE PHOTOSYNTHETIC ASCOGLOSSAN ELYSIA-TIMIDA AND THE CHLOROPHYCEAN ACETABULARIA-ACETABULUM
DYNAMICS OF A PECULIAR PLANT HERBIVORE RELATIONSHIP - THE PHOTOSYNTHETIC ASCOGLOSSAN ELYSIA-TIMIDA AND THE CHLOROPHYCEAN ACETABULARIA-ACETABULUM
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DOI：
10.1007/bf00346186
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发表时间：
1992-04-01
期刊：
影响因子：
2.4
通讯作者：
ROS, JD
中科院分区：
文献类型：
--
作者：
MARIN, A;ROS, JD
Ascoglossan软体动物Elysia timida Risso，1818保留了来自其藻类食物的功能性叶绿体，绿藻纲的髋臼藻（L.）。质体光合产物是软体动物重要的有机营养物质来源。叶绿体开发具有生态功能，允许子囊孢子完全以藻类为食，这对其他食草动物来说是有限的，季节性的。1987年10月至1988年7月，在西班牙东南部的马扎龙湾的一个海湾中研究了软体动物和藻类种群的年度演变。软体动物的种群密度高度依赖于其食物供应，受藻类种群的季节性生命周期控制。在其生命周期中，软体动物的放牧程度随着藻类钙化的增加而降低，藻类的细胞壁逐渐钙化，最终高度钙化的茎完全抵抗子囊藻的放牧。相反，在季节循环中，软体动物对藻类叶绿体的利用增加。在季节循环中，食物的逐渐缺乏可能导致了E.蒂米达。子囊孢子的发育策略在一年中也会发生变化：当食物丰富时（11月、12月、1月、2月和3月），它是直接的，没有浮游幼虫阶段;当食物缺乏时（10月、4月、5月和6月），它是卵营养的，有一个短暂的浮游幼虫阶段。叶绿体保留作为一种缓冲，减轻每年的密度，结构和丰富的贝类的营养状态的变化的影响。
The ascoglossan mollusc Elysia timida Risso, 1818 retains functional chloroplasts from its algal food, the chlorophycean Acetabularia acetabulum (L.). Photosynthates from the plastids are an important source of organic nutrients for the mollusc. Chloroplast exploitation has an ecological function, allowing the ascoglossan to live entirely on an algal diet which is of limited, seasonal availability to other herbivores. Between October 1987 and July 1988, the annual evolution of the molluscan and algal populations was studied in a cove of Mazarron Bay, southeast Spain. The population density of the mollusc is highly dependent on its food supply, being controlled by the seasonal life cycle of the algal population. During its life cycle, the degree of grazing by the mollusc decreases with increasing algal calcification, the cell walls of the alga progressively calcify, and the eventually highly calcified stalks are completely resistant to ascoglossan grazing. In contrast, the exploitation of the algal chloroplasts retained by the molluscs increases during the seasonal cycle. The progressively increasing scarcity of food during the seasonal cycle may have led to the retention of symbiotic chloroplasts by E. timida. The developmental strategy of the ascoglossan also changes during the year: when food is abundant (in November, December, January, February and March) it is direct, with no planktonic larval phase, when food is scarce (in October, April, May and June) it is lecithotrophic, with a short planktonic larval phase. Chloroplast retention acts as a buffer, alleviating the effects of annual changes in density, structure and abundance of the alga on the nutritional state of the mollusc.