广西防城海草光合作用研究-生态学专业论文.docxVIP

明显加·陕，说明矮大叶藻具有较强的利用HC03作为无机碳源的能力。 明显加·陕，说明矮大叶藻具有较强的利用HC03作为无机碳源的能 力。 水分丧失是潮间带海草所面临的最大环境胁迫。当水分丧失超 过50％时，Fv／Fm趋于线形下降，虽然矮大叶藻可以忍耐一定程度的 失水，但是过分失水则会导致死亡。 矮大叶藻在盐度是25。35之间显示出最大的光合速率，高盐度下 的光合速率要高于低盐度下的，体现了矮大叶藻对盐生环境的适应。 通过对野外矮大叶藻光合速率的季节变化的测定发现，在春、秋 两季光合速率较高，而夏季光合速率最低，这是由光照、温度、潮汐 等几个因素共同决定的，其中潮汐起着关键的作用。 研究结果表明，矮大叶藻是一个适应性较强的海草种类，对各 个环境因子都有较强的耐受能力。其中，光照和无机碳浓度是其光合 作用最主要的限制因子。由于它处于潮闻带，潮汐对其存活起着关键 的调节作用。 关键词：海草矮大叶藻光合作用光照无机碳 STUDY STUDY ON PHOTOSYNTHESIS 0F SEAGRASS Z傩刀互见4 JAPD?、7：，(■IN R悄GCHENG OF GUANGⅪ ABSTRACT Seagrass ale higher-level plants lived in the intertidal and subtidal zone，andⅡley are a small but diverse group of mostly submersed marine angiosperms，which inhabit environments that characterized by periodic ught limitation and high salinity．Seagrass bed is one of the major nearshore habit types and plays a important role in marine ecosystems． The hi曲productivity of seagrass beds places them among the most production of all marine ecosystems．But the global change and human activity have led to the large scale loss of seagrass．For protection and recovery ofseagrass，we should study their photosynthetic ecophysiology． The objective of this study aims to reveal the photosynthesis of Zostera japonica effected by factors such as light，temperature，inorganic carbon, salinity and water stress．This study combines the laboratory and the field experiment to analyze the relationship between the photosynthesis of Zosterajaponica and environment factors． IV The The net photosynthetic rate and respirating rate generally increased in response to increasing temperature for photosynthesis within the range 15-30*(2 and the observed trends suggested the optimum temperature range for photosynthesis was between 25-30。C，below the 20。Cthe photosynthetic rate dropped sharply．Also with the increasing light intensity the net photosynthetic rate increased and the optimum light intensity is about 20000Ix．The compensation light intensity range Was between 100·400Ix．According to examine the vertical d