中国水产科学Issue(4)：843-850,8.DOI:10.3724/SP.J.1118.2013.00843
高HCO3-浓度对细基江蓠繁枝变型生长及生理生化特征的影响
Effect of high HCO3- concentrations on the growth, physiology, and biochemistry of Gracilaria tenuistipitata
摘要
Abstract
The total amount of dissolved inorganic carbon in water includes CO2, H2CO3, HCO3−, and CO32-. At a pH of between 8.2–8.4, HCO3−is the predominant component (approximately 90%), and free CO2 contributes less than 1%. In China, saline-alkali water covers about 45.87 million ha, most of which is characterized by high car-bonate alkalinity (CA) concentrations. Since high CA is a major stressor for living organisms, most of these sa-line-alkali water areas have little evidence of life. To take advantage of this unexploited resource, researchers have trialed the use aquatic plants to reduce the HCO3−concentration in saline-alkali waters. The seaweed Gracilaria tenuistipitata var. liui Zhang et Xia is characterized by rapid growth and easy cultivation. The objective of this study was to investigate the effects of high HCO3−concentrations on the growth, physiology, and biochemistry of G. tenuistipitata to provide basic information for the development of saline-alkali water using macroalga. G. tenuisti-pitata were grown for 10 d in a 250 mL Erlenmeyer flask containing 200 mL culture medium with 1.8 (control), 12, 24, 36, or 48 mmol/L HCO3−. We then compared the physiological and biochemical characteristics of G. tenuisti-pitata among the different treatment groups. The water temperature(25℃±1℃), salinity (20), initial pH (8.2-8.4), light intensity (5 000 lx), light-dark cycle (12D︰12h), and algae density (5 g/L) were the same for all groups. The specific growth rates (SGR) of G. tenuistipitata in the high HCO3−concentration groups were significantly higher than in the control after 10 d exposure (P<0.05), suggesting that the increase in HCO3−enhanced growth in G. te-nuistipitata. The effect may have been mediated by an increase in the available carbon (e.g., CO2) in the water. The increase in HCO3−was associated with a gradual decrease in chlorophyll a, phycoerythrobilin, and carotenoid content in G. tenuistipitata, suggesting the increase in HCO3− had a negative effect on the synthesis of of photosynthetic pigments, and led to membrane lipid peroxidation. In addition, the SGR and superoxide dismu-tase (SOD) and peroxidase (POD) activity increased in G. tenuistipitata as the concentration of HCO3− increased from 1.8 to 24 mmol/L, then decreased in the range between 24 to 48 mmol/L. HCO3− content was significantly correlated with the content of chlorophyll a (P<0.01), phycoerythrobilin, carotenoids, and malonaldehyde (P<0.05). SGR was significantly correlated with SOD activity (P<0.05), but not with the content of photosynthetic pigments, suggesting that the inhibitory effect of high HCO3−concentration on the growth of G. tenuistipitata may damage the antioxidant system, not the photosynthetic system. With regard to the growth of G. tenuistipitata, high HCO3− concentrations appear to be beneficial by increasing the availability of inorganic carbon for the photosyn-thesis. However, the tradeoff is the production of CO −which forms a CaCO3 precipitate with Ca2+, reduces the 2 3 synthesis of photosynthetic pigments, and causes damage to the membrane system. The antioxidant defense system appeared to protect G. tenuistipitata at HCO3−concentrations of <24 mmol/L. However, antioxidant activity (e.g., SOD and POD) was significantly impaired at HCO3−concentrations of>24 mmol/L, suggested the defense system was damaged. As a result, the SGR of G. tenuistipitata was lower at these concentrations. Based on our results, an HCO3− concentration of 24 mmol/L appears optimal for the growth of G. tenuistipitata, and concentrations <24 mmol/L appear to be detrimental.关键词
HCO3-浓度/细基江蓠/特定生长率/光合色素/抗氧化酶/丙二醛Key words
HCO3-/Gracilaria tenuistipitata/specific growth rate/photosynthetic pigment/antioxidase/malonal-dehyde content分类
农业科技引用本文复制引用
..高HCO3-浓度对细基江蓠繁枝变型生长及生理生化特征的影响[J].中国水产科学,2013,(4):843-850,8.基金项目
中国水产科学研究院基本科研业务费专项(2012A0801) （2012A0801）
