光照对坛紫菜生长和无机碳利用的影响

］以坛紫菜Z-61品系为研究材料，分析坛紫菜叶状体和丝状体在三种光强（10，50，500 μmol·m-2·s-1）下的应答。发现:1）坛紫菜叶状体和丝状体的光系统 Ⅱ 最大量子产量及叶绿素a和藻红蛋白的含量都随光强增加而降低，但净光合速率、最大光合速率、胞外碳酸酐酶活性和总碳酸酐酶活性则随光强增加而增加。2）当光强从10 μmol·m-2·s-1增加到500 μmol·m-2·s-1时，坛紫菜叶状体的生长速率约增加77%；丝状体的生长速率先增加后降低，在光强500 μmol·m-2·s-1下达到最低，比在10 μmol·m-2·s-1下显著下降了约90%。3）在三种光强下，坛紫菜叶状体的最大光合速率、光系统 Ⅱ 最大量子产量和生长速率都大幅高于丝状体。这些结果表明:坛紫菜的光系统 Ⅱ、光合作用与生长对光强的应答并不完全一致；叶状体比丝状体更适应高光，这可能是长期进化的结果；光强可以改变坛紫菜对无机碳的吸收。

Differences in the Light Response of Thallus and Conchocelis ofEconomic Seaweed Pyropia haitanensis on Growth and Photosynthesis

Pyropia haitanensis strain Z-61 was used as the study material to analyze the responses of conchocelis and thallus to three light intensities(10,50,500 μmol·m-2·s-1).The maximum photosystem Ⅱ quantum yield,and chlorophyll a and phycoerythrin content of conchocelis and thalli were found to decrease with increasing light intensity,but the net photosynthetic rate,maximal photosynthetic rate,extracellular carbonic anhydrase activity and total carbonic anhydrase activity of conchocelis and thalli increased with increasing light intensity.When the light intensity increased from 10 μmol·m-2·s-1 to 500 μmol·m-2·s-1,the growth rate of thalli increased by about 77%,while the growth rate of conchocelis increased and then decreased,reaching a minimum at 500 μmol·m-2·s-1,with a significant decrease of about 90% compared with that at 10 μmol·m-2·s-1.In addition,the maximal photosynthetic rate,maximum photosystem Ⅱ quantum yield and growth rate of thallus were substantially higher than those of conchocelis under all three light intensities.These results indicated that there are significant differences between responses of photosystem Ⅱ,photosynthesis and growth of P.haitanensis to light intensity,and that thalli are more adapted to high light than conchocelis,which may be the result of long-term evolution.Light intensity can change the uptake of inorganic carbon by P. haitanensis.