潮间带大型海藻应对UV-B辐射及克生作用压力的复合响应分析

The intertidal zone is an interlocking region of marine and terrestrial ecosystems, which is one of the most sensitive zones of the biosphere. Macroalgae living in this transitional zone are inevitably exposed to harmful UV-B irradiation (280-315nm). Furthermore, competition between macroalgal species in the same or similar niche due to niche overlaping can not be ignored. Therefore, intertidal macroalgae have to cope with environmental stresses from both UV-B radiation and allelopathic effect. In the present study, the integrated response of several representative macroalgae to UV-B radiation and allelopathic effects will investigated at physiological and biochemical levels. The interaction between quantified allelopathic effects and various UV-B radiation doses will also be approached. We will investigate the differencial expression of several isozymes such as SOD, POX, CAT and APX in different macroalgal species under complex environmental conditions. Comparison gene expression profiles of typical antioxidant enzymes will be determined using real-time quantitative RT-PCR technology. Mechanisms of specific metabolic pathways and in vivo or in vitro changes of the allelochemicals in macroalgae after exposed to UV-B radiation will also be elucidated. These studies will reveal the intrinsic biochemical mechanisms of the intertidal macroalgae response to environmental stresses.

潮间带是陆地生态系统和海洋生态系统的交错地带，属生物圈中最敏感的生态系统之一。栖息于此生境中营固着生活的大型海藻不可避免地受到UV-B辐射（280-315nm）的危害。同时，处于相同或相近生态位的海藻间由于生态位的重叠，必然存在种间的相生相克作用。因此，UV-B辐射和克生作用是共存的，是潮间带大型海藻必须要同时应对的环境压力。本项目拟选择几种代表性的潮间带大型海藻，研究其在生理生化水平上对紫外辐射及克生作用压力复合效应的变化响应，探索量化后的克生作用及UV-B剂量间的互作效应；分析不同种类海藻的不同同工酶在复合环境效应时其表达上的差异；采用实时定量RT-PCR技术获得典型抗氧化酶基因差异表达；阐明UV-B辐射胁迫时海藻体内或体外克生化合物的具体代谢途径及变化。这些研究将较为系统地揭示潮间带海藻响应潮间带环境压力的内在生化机制。

栖息于潮间带这一特殊地理位置的大型海藻不可避免地受到UV-B辐射（280-315nm）的危害。同时，处于相同或相近生态位的海藻间由于生态位的重叠，必然存在种间的相生相克作用。因此，UV-B辐射和克生作用是共存的，是海藻必须要同时应对的环境压力。二者相互作用从而达到竞争的相对平衡状态，但在较强的紫外辐射时这种竞争情况可能又会有所改变。因此，研究潮间带大型海藻对UV-B辐射增强或克生单独作用的响应变化并不能反映实际的生态过程，只有研究潮间带大型海藻对UV-B和克生的复合效应的响应规律才具有真正的意义。本研究选择几种代表性的潮间带大型海藻，研究了其在生理生化水平上对紫外辐射及克生作用压力复合效应的变化响应，从活性氧角度阐明两环境因素复合效应对潮间带大型海藻的作用规律；验证不同种类海藻的各种同工酶的基因表达趋势与环境胁迫的相关性问题，分析其在复合环境效应时其表达上的差异；采用实时定量RT-PCR技术分析了典型抗氧化酶基因的表达量差异；GC/MS分析紫外胁迫时海藻体内或体外克生化合物的代谢具体途径及量的变化，系统地揭示潮间带海藻响应潮间带环境压力的内在生化机制及适应策略。