The phenology of sexual reproduction by green algae (Bryopsidales) on Caribbean coral reefs
The phenology of sexual reproduction by green algae (Bryopsidales) on Caribbean coral reefs
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DOI：
10.1046/j.1529-8817.1999.3510024.x
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发表时间：
1999-02-01
影响因子：
2.9
通讯作者：
Clifton, LM
中科院分区：
文献类型：
--
作者：
Clifton, KE;Clifton, LM
最近对热带绿藻（Bryopsidales）同步释放配子的高度组织化、物种特异性和性别特异性模式的实地观察，邀请了对热带珊瑚礁群落重要组成部分的生态学和生活史的各种未来研究。本文详细介绍了5个常见属（Caulerpa、haalimeda、Penicillus、Rhipocephalus和Udotea） 22种藻类的有性繁殖，包括与繁殖有关的空间发生、时间和颜色变化的野外观察，配子大小和行为的数据，以及当地物种丰度的一致变化的描述。生态上短暂的有性繁殖涉及宏观变化，这些变化可靠地表明发育状态和性别身份。从受精开始到配子释放的时间分别为36 h （halmeda）、48 h （Caulerpa、青霉菌和Rhipocephalus）和96 h （Udotea）。所有种都产生鞭毛的、负浮力的异配子，所有种的小配子大小相似；然而，在大配子的大小上发现了相当大的种特异性差异。在Caulerpa、haalimeda和Udotea flabellum (Ellis and Solander) Lamouroux中，大配子与小配子的体积比为2:1 ~ 45:1，而在Penicillus spp、Rhipocephalus phoenix (Ellis and Solander) Kuetzing和其他Udotea属中，大配子的异配子比例为10(4):1，Caulerpa和haalimeda的大配子表现出强烈的正向趋光性。虽然只有一小部分（一般约5%）的菌体代表每个物种在给定的早晨释放配子，但大多数物种在繁殖活动的季节性高峰（3 - 5月）进行了多次有性繁殖。正如全新世物种所预料的那样，当地藻类丰度的急剧下降与这些时期相吻合。在1997年的这3个月期间，沙生属（例如青霉属）的密度下降了80-90%。蔓生物种如总状茎藓（Caulerpa racemosa） （(Forsskal) J. Agardh）的覆盖面积也出现了类似的下降，暴露出大片（35-50米(2)）以前生长过度的珊瑚礁基底。
Recent field observations of highly organized, species- and sex-specific patterns of synchronous gamete release by tropical green algae (Bryopsidales) invite a variety of future studies into the ecology and life histories of an important component of tropical reef communities. This paper details sexual reproduction by 22 algal species within five common genera (Caulerpa, Halimeda, Penicillus, Rhipocephalus, and Udotea), including field observations on the spatial occurrence, timing, and color changes associated with fertility, data on gamete size and behavior, and descriptions of coincident changes in local species abundances.Ecologically ephemeral episodes of sexual reproduction involved macroscopic changes that reliably indicated developmental state and sexual identity. The time from onset of fertility to gamete release was 36 h (Halimeda), 48 h (Caulerpa, Penicillus, and Rhipocephalus), or 96 h (Udotea). All species produced flagellated, negatively buoyant, anisogamous gametes, Microgametes of all species were similar in size; however, considerable species-specific differences were seen in the size of macrogametes. In Caulerpa, Halimeda, and Udotea flabellum (Ellis and Solander) Lamouroux, the volumetric ratio of macrogametes to microgametes ranged from 2:1 to 45: 1, whereas more extreme levels of anisogamy (10(4):1) were observed for Penicillus spp., Rhipocephalus phoenix (Ellis and Solander) Kuetzing, and other Udotea spp, The macrogametes of Caulerpa and Halimeda showed strong positive phototaxis.Although only a subset (generally about 5%) of the thalli representing each species released gametes on a given morning, most species underwent bouts of sexual reproduction on numerous occasions during the seasonal peak of reproductive activity (March-May), As might be expected for holocarpic species, dramatic declines in local algal abundance coincided with these periods. The density of sand-dwelling genera such as Penicillus fell by 80-90% during this 3-month period in 1997. Similar declines in the cover of sprawling species such as Caulerpa racemosa ((Forsskal) J. Agardh) exposed large (35-50 m(2)) sections of previously overgrown reef substrate.