| ASPECTS OF IRON NUTRITION IN MACROALGAE ULVA PERTUSA （CHLOROPHYTA） UNDER IRON STRESS |
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| 摘 要： |
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| 关 键 词： | 营养学 石莼 铁 叶绿素 含氮量 色素 近赤道的 |
| 收稿时间： | 27 April 2000 |
| 修稿时间： | 21 May 2001 |
Aspects of iron nutrition in macroalgaeUlva pertusa (Chlorophyta) under iron stress |
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| Authors: | Liu Jing-wen Dong Shuang-lin Liu Xiao-yun |
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| Institution: | (1) Aquaculture Research Laboratory, Ocean University of Qingdao, 266003 Qingdao, China |
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| Abstract: | Fe, Chlorophyll (Chl) and total nitrogen (TN) content in tissues were measured in Fe-deficient cultures ofUlva. pertusa over a period of 60 days. Photosynthetic carbon fixation rates were studied at the start of and 30 days after Fe-deficiency
culture, when the effects of Fe-deficiency on the ultrastructure were also analyzed. The iron content in tissue decreased
exponentially during Fe-deficiency (from 726.7 to 31.6 μg/gdw) and simultaneously Chl and TN content declined to 4.35% and
59.9% of their original levels respectively. Maximum carbon fixation rate (50–250 μmol/m2 s) under Fe-deficiency decreased significantly compared with the control (p<0.01) and was 13.6 to 0.365 μg C/cm2 h. Photosynthesis in Fe-deficient cells became light-saturated at lower irradiance than that in control. Ultrastructural
observations of Fe-deficient cells showed reductions in chloroplast number, some degeneration of lamellar organization, an
increase in vacuolar area, a decrease in mitochondrial matrix density, and variation in accumulation body number and morphology.
During Fe-deficiency, the algae growth rate continued to decline and after 6 weeks of iron deficiency, no further growth was
detectable. These suggested that the lower growth rate ofUlva. pertusa under Fe-deficiency could be due mainly to nitrogen utilization and inhibition of photosynthesis.
This project No. 39725023 supported by NSFC for Talented Youths and the Project under the Major State Basic Research of China
(Grant No. G1999012011). |
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| Keywords: | intracellular nitrogen and iron pigment carbon fixation ultrastructure Ulva pertusa iron stress macroalgae |
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