| 摘要: |
| [目的]探讨大型海藻龙须菜(Gracilaria lemaneiformis)碳氮利用对紫外辐射(UVR)的响应,揭示可利用氮在其中的调节作用。[方法]设置2种硝氮浓度(低氮,50 μmol·L-1;高氮,500 μmol·L-1)和3种不同波长的光辐射处理(P,395~700 nm;PA,320~700 nm;PAB,295~700 nm),龙须菜叶状体在上述不同条件下适应培养25 d后,测定藻体的硝氮和无机碳利用情况。[结果]PA和PAB条件下培养的龙须菜,对硝氮的最大吸收速率显著升高,尤其在高氮条件下升高更加明显。P条件下,高氮适应培养的藻体硝酸还原酶(nitrate reduscate,NR)活性显著降低;但在PA和PAB下没有发现这种氮营养史的影响。UVR显著降低了龙须菜的最大光合固碳速率(Pmax)和对外源无机碳的半饱和常数(KDIC),提高了总碳酸酐酶(carbonic anhydrase,CA)的活性。高氮适应下藻体的最大光合固碳速率和总CA活性显著升高,同时半饱和常数显著降低。[结论]UVR的存在能够促进龙须菜对外源硝氮的吸收利用,抑制海藻光合固碳能力,但可利用氮的加富可以缓解UVR对龙须菜光合作用的抑制。 |
| 关键词: 龙须菜 紫外辐射 硝氮 氮利用 碳利用 |
| DOI： |
| 投稿时间：2015-06-11修订日期：2015-07-10 |
| 基金项目:国家自然科学基金项目(41376129),海洋公益性行业科研专项经费项目(201305005,201305021),山东半岛近岸海域生态模拟实验研究项目,青岛市市南区科技发展资金项目(2013-12-005-SW)和山东省海洋生物研究院院长基金项目(SZJJ201304)资助。 |
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| Effects of Ultraviolet Radiation and Different Nitrate Concentration on Carbon and Nitrogen Utilization of Gracilaria lemaneiformis Grown |
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XU Zhi-guang1,2, ZHU An-cheng1, WU Hai-yi1,2
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| (1.Marine Biology Institute of Shandong Province, Qingdao, Shandong, 266104, China;2.Macroalgae Engineering Technology Centre of Qingdao, Qingdao, Shandong, 266104, China) |
| Abstract: |
| [Objective] To investigate carbon and nitrogen utilization of Gracilaria lemaneiformis responding to ultraviolet radiation (UVR), and reveal the regulation of available nitrogen in this process.[Methods] Two nitrate treatments with different concentration (L-N,50 μmol·L-1 and H-N,500 μmol·L-1) and three radiation treatments with different wavelength range(P,395~700 nm;PA,320~700 nm;PAB,295~700 nm) were used, and thalli were cultured under different conditions for 25 d to determine the nitrogen and carbon utilizations.[Results] The results showed that the maximal nitrate uptake rate of alga exposed to UVR increased significantly,especially under H-N condition.Adaptive cultivation to H-N remarkably enhanced nitrate reductase activity in alga with UVR, while had no effect on them without UVR.UVR exposure decreased the maximal photosynthetic carbon fixation rate (Pmax) and semi saturation constant of carbon utilization (KDIC),while raised carbonic anhydrase (CA) activity in alga. Compared to L-N condition, both Pmax and CA activity increased, and KDIC decreased significantly in thalli cultured in H-N condition.[Conclusion] These results suggested that UVR exposure stimulated nitrogen uptake and inhibited carbon utilization in Gracilaria lemaneiformis.However enrichment of available nitrogen could alleviate the inhibition on photosynthetic carbon fixation caused by UVR exposure. |
| Key words: Gracilaria lemaneiformis UVR nitrate nitrogen utilization carbon utilization |
