海带配子体和幼孢子体无机碳素营养的比较研究

IOCAS-IR > 海洋环流与波动重点实验室

	海带配子体和幼孢子体无机碳素营养的比较研究
	岳国峰
学位类型	博士
	2000
学位授予单位	中国科学院海洋研究所
学位授予地点	中国科学院海洋研究所
学位专业	海洋生物学
关键词	海带幼孢子体配子体碳酸酐酶
摘要	采用pH漂移技术并结合Az、DIDS、SITS等抑制剂，研究了海带生活史不同世代－幼孢子体和配子体利用外源无机碳的途径以及无机碳对其光合碳利用的影响。结果表明：幼孢子体对无机碳的利用能力远远高于配子体，两者在密闭培养体系中光合碳利用均不改变海水碱度，因些可以用pH的变化直接指示无机碳的变化。在天然海水中(pH 8.1-8.3)，海带幼孢子体外源无机碳的利用形式主要是HCO_3~-,HCO_3~-由膜外碳酸酐酶(CA)水解成CO_2后扩散进入细胞，这种形式占全部无机碳供应的75％，其余的来自于游离CO_2，没有发现HCO＿3~-直接转运机制的存在；而配子体不具有膜外碳酸酐酶，只以海水中游离CO_2为碳源。提高海水中无机碳的浓度均能增加海带幼孢子体对无机碳的利用速率：当无机碳的浓度达到3.5mmol/L时，幼孢子体对元机碳的利用速率达到最大值；配子体利用无机碳的速率也随着海水中游离CO_2浓度的升市而升高，当游离CO_2浓度到饱和时，雌雄配子体的光合碳利用速率分别比在天然海水中提高了2.9倍和2.5倍，说明天然海水中的无机碳不能满足其最大生长的需要。在天然海水pH变化范围内(pH 8.1-8.3), pH本身不影响配子体光合碳利用速率，当pH高于8.3时，配子体碳利用速率随pH的升高而降低。优化海带配子体培养条件时维持海水培养基低pH (pH 8.1-8.3)及高CO_2浓度是保证无机碳素充分供应的基本条件。
其他摘要	The ways of inorganic carbon acquisition by juvenile sporophyte and gametophyte of L. japonica * L. longissima different generation of its life history have been investigated, including the effect of inorganic carbon on their photosynthesis by means of pH-drift technique and inhibitors as acetazolamide (Az), 4',4'-sothiocyanatosilbene-2,2-disulfonic acid (DIDS), 4-acetamido-4'-isothiocyano-2,2'-stibene-disulfonate (SITS). The results reveal:juvenile sporophyte has rather higher ability of utilizing inorganic carbon than that of gametophyte, but both of them don't change alkalinity of seawter in the course of light-depended carbon acquisition in the closed system, so change of pH can be used revealing variation of inorganic carbon directly if the change of temperature and saltlity is neglectable. The inhibitor of external carbonic anhydrase (CA)-Az can strongly inhibit carbon uptake by juvenile sporophyte of L. japonica * L. longissima. External CA dehydrating HCO_3~- to free CO_2 is the main pathway of inorganic carbon utilization by juvenile sporophyte, accounting for 75 percentage of total inorganic carbon acquired in natural seawater (pH 8.1-8.3) and 100 percentage when the concentration of free CO_2 is near to zero (pH 9.1). Only 25 percentage comes from free CO_2 in natural seawater (pH 8.1-8.3). No direct uptake of HCO_3~- has been found. Contrast to juvenile sporophyte, gametophyte can use only free CO_2 which doesn't posses external carbonic anhydrase. The rate of inorganic carbon acquisition by both juvenile sporophyte and gametophyte would increase with the increase of the concentration of inorganic carbon: juvenile sporophyte gains its maximum rate of carbon acquisition at the concentration of 3.5mmol/L; female and male gametophyte can increase their rate of carbon acquisition 2.9 and 2.5 times under condition of CO_2 saturation than that in natural seawater, which indicates the concentration of inorganic carbon in natural seawater can't meet the need of optimal growth of L. japonica *L. longissima. When pH changes between 8.10-8.30, pH doesn't affect the rate of carbon utilization by gametophyte. But higher than that, the rate of carbon utilization by gametophyte would decrease with the increase of pH. Optimizing culture condition of gametophyte should abide by such principle as maintaining lower pH and higher CO_2 concentration.
页数	89
语种	中文
文献类型	学位论文
条目标识符	http://ir.qdio.ac.cn/handle/337002/1475
专题	海洋环流与波动重点实验室
推荐引用方式 GB/T 7714	岳国峰. 海带配子体和幼孢子体无机碳素营养的比较研究[D]. 中国科学院海洋研究所. 中国科学院海洋研究所,2000.

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