摘要
于１９９８年３月在青岛太平角采集条斑紫菜，在室内光照强度为１２０μＥ／（ｍ~２·ｓ）的培养架上培养，通过测定其光合作用引起密闭海水体系ｐＨ值及无机碳浓度的变化，借助于各种无机碳利用的抑制剂（Ａｚ、Ｖａｎ、ＤＩＤＳ、ＳＩＴＳ）对其无机碳利用机制进行了研究。结果表明，（１）条斑紫菜可间接吸收ＨＣＯ^（－）_（３）。胞外碳酸醉酶（ＣＡ）催化ＨＣＯ^（－）_（３）水解成ＣＯ_２扩散进入胞内是条斑紫菜无机碳利用的主要形式，占全部无机碳利用的７３％以上。Ａｚ是胞外ＣＡ的抑制剂，可直接检测胞外ＣＡ的存在，它不能透过细胞膜。（２）条斑紫菜可依赖于细胞膜上ＡＴＰ酶对ＨＣＯ^（－）_（３）直接转运。但未发现带Ⅲ蛋白（ｂａｎｄ ３ Ｐｒｏｔｅｉｎ）及 Ｎａ~＋／ＨＣＯ_（３）^（－）协同转运系统的参与。（３）条斑紫菜ｐＨ值补偿点为９．８３，ＣＯ_２补偿点为０．０４μｍｏｌ／Ｌ。
The mechanisms of inorganic carbon utilization were studied on the red macroalga Porphyra yezoensis Ueda (collected in the Taiping Bay Qngdao in Mar., 1998) by pH drift technique in a closed system by means of vacuous ichibitors: Acetazolamide (Az), Vanadate (Van), 4', 4' -diisothiocyanatosilbene-2. 2-disulfonic acid (DIDS) and 4-acetamido-4' -isothiocyano -2, 2' -stibene-disulfonate (SITS). The results indicate that (1) Porphyra yezoensis can uptake HCO_3 indifectly. Inorganic carbon utilization of Porphyra yezoensis can be strongly inhibited by 100μmol/L Az which inhibits external CA and regain its full photosynthetic capacity after rinsed three times. Dissolved inorganic carbon was reduced 0.41mmol/L in two hours due to photosynthesis and only 0.11mmol/L by addition of Az. Hence, external carbonic anhydrase dehyforng HCO3- to CO2 is the main pathway of inorganic carbon utilization by Porphyra yezoensis, accounting for at least 73 percentage of total inorganic carbon acquisition. External CA can be detected simply by Az which cannot penetrate the plasma membrane. (2) Porphyra yezoensis can also transport HCO_3 directly dependent-ATPase as viewed by Van and DIDS inhibition Band three protein and Na+ /HCO3 cotransport system have not been found involving in the direct HCO_3 transpoftation since SITS has no affection on carbon acquisition. (3) Porphyra yezoensis has a higher pH compensation point and a lower CO_2 compensation point: 9.83 and 0.04μmol/L, respectively.
出处
《海洋与湖沼》
CAS
CSCD
北大核心
2000年第3期246-251,共6页
Oceanologia Et Limnologia Sinica
基金
国家"九五"科技攻关项目!96-C01-05-01
关键词
条斑紫菜
无机碳利用
间接吸收
碳酸酐酶
Porphyra yezoensis Ueda Inorganic carbon Indirect uptake Direct transporta- tion Carbonic anhydrase
