青岛三种海产红藻的光合和呼吸特性的初步研究

A STUDY ON THE PHOTOSYNTHETIC AND RESPIRATORY PROPERTIES OF THREE RED SEAWEEDS IN QINGDAO

于1981年在青岛近海采集真江食、石花莱和角叉菜样品，用氧电极法测定它们在不同生长季节和发育阶段的光合和呼吸速率，并研究不同温度对其光合和呼吸速率的影响，同时计算出它们的呼吸温度系数。结果表明，3种红藻具有典型的潮间带海藻的光合特性，即高光饱和点为600—1000μE／（m2·s），较高的光补偿点为12－40μE／（m2·s）和较高的光合适温≥25℃。温度对3种红藻的光合和呼吸的影响均很明显，在5，15，25℃下测试，它们的最高光合和呼吸速率都出现在25℃。3种红藻的呼吸温度系数（Q10），在5－15℃较高，为1．4－5．5在15－25℃较低，为1．1－2．7。说明它们在低温下的呼吸受温度变动影响较大。经计算3种红藻在适宜生长温度下的净光合速率：角又菜和真江蒿在15℃分别为4．90O2mg／（g·h）和8．14O2mg／（g·h）；石花菜在25℃为11．87O2mg／（g·h），在3种红藻中最高。这说明，石花菜的光合效率并不象人们预料的那样低，其秋季幼体在25℃，1000μE／（m2·s）光强下，净光合速率达到19．19O2mg／（g·h）。看来在自然界石花菜生长缓慢主要是由于生境中低光照强度和较低水温所致。

Photosynthetic and respiratory rates of three red seaweeds, Gracilaria asiatica, Gelidium amansii Lamx. and Chondrus sp. collected from the coast of Qingdao in 1981, were studied by using oxygen electrode technique in reahon with different growing seasons and development stages of the plants. The effect of temperature on photosynthesis and respiration was also investigated, and the temperature coefficient of respiration was calculated.The results showed that the three red seaweeds were similar to the eulittoral species in photosynthetic properties, having higher light saturation points 600 - 10000μE /(m2·s) and light compensation points 12 -40μp E /(m2· s) of photosynthesis as well as higher temperatures (≥25℃) for photosynthesis. Their photosynthetic and respiratory rates were significantly affeCted by tCmperaturc, with the high values at 25℃. The temperature coefficients of respiration of the red seaweeds were 1.4- 5.5 at 5 - 15℃ and 1.1 - 2.7 at 15- 25℃, and at the favourable growth temperatures, the net photosynthetic rates were 4.90 O2mg /(g·h) for Chondrus sp. and 8. 14 O2mg /(g· h) for Gracilaria asiatha at 15℃, and 11 .87 O2mg (g·h ) for Gelidium amansii at 25℃. The uet pnotosynthetic rate of the immature G. amansii in autumn was 19. 19 O2mg /(g·h) at 25℃ and 1000μE /(m2·s ). Therefore, Gelndum amansii has an unexpectedly high effidency of photosynthesis and it seems as if the low growth rate in its habitat is caused by low light intensity and low temperature, so the productivity might be raised even higher under certain artiflcial culture conditions of higher light intensity and favourable temperature.