| 摘要: |
| 浒苔（Ulva prolifera）引起的大规模绿潮起源于黄海南部，在向北迁移过程中生物量迅速扩增，在海州湾附近（35°N左右）迅速增加达到峰值。在绿潮漂浮迁移过程中，海水表层温度、溶解无机氮（dissolved inorganic nitrogen，DIN）和磷酸盐（PO43--P）变化显著。本文以迁移过程中的浒苔为研究对象，分析了环境要素变化与浒苔藻体的生物学特征间的关系。结果显示，随着绿潮的漂浮迁移，浒苔藻体光系统Ⅱ最大光化学量子产量Fv/Fm从0.7逐渐降低至0.45左右，光系统Ⅱ实际光化学量子产量Y（Ⅱ）从0.55逐渐降至0.25左右；硝酸还原酶活性（nitrate reductase activity，NRA）从2.7 μmol/L NO2-/（mg·h）降至0.5 μmol/L NO2-/（mg·h）左右；生殖分配率（RA）从15%逐渐上升至50%左右。相关性分析表明，DIN与浒苔藻体的生物学特征相关性呈极显著，表明在漂浮迁移中，DIN对浒苔的生物学特征至关重要。温度对浒苔藻体光合活性和NRA的影响极显著；光照强度对浒苔藻体光合活性的影响极显著，对NRA的影响显著；盐度和PO43--P显著影响浒苔藻体的光合活性和NRA，而这四种环境要素与浒苔形成生殖细胞的相关性不显著。本文认为，绿潮漂浮迁移过程中，浒苔藻体光合活性、营养盐吸收等生物学特征对环境中DIN的变化响应最敏感，其他环境要素对浒苔藻体的影响程度大小依次为温度、PO43--P、盐度和光照强度。绿潮漂浮迁移过程中环境要素的变化直接影响了浒苔的生长与生殖，尤其是海州湾附近（35°N左右）是浒苔藻体状态改变的分水岭。 |
| 关键词: 浒苔 环境要素 光合活性 生殖分配率 硝酸还原酶活性 |
| DOI：10.11693/hyhz20200400110 |
| 分类号:Q178.1;X55 |
| 基金项目:国家重点研发计划，2016YFC1402102号；国家自然科学基金，41706121号，41976132号；国家自然科学基金-山东联合基金，U1806213号，U1606404号；中央高校基础研究经费，201964025号。 |
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| CORRELATION ANALYSIS OF ENVIRONMENTAL FACTORS AND BIOLOGICAL CHARACTERISTICS OF ULVA PROLIFERA DURING GREEN TIDES DRIFTING |
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GUAN Chen1, HAO Ya1, HOU Cheng-Zong1, TANG Xue-Xi1,2, WANG Ying1,2
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1.College of Marine Life Sciences, Ocean University of China, Qingdao 266100, China;2.Marine ecology and Environmental Science Laboratory, Pilot National Laboratory for Marine Science and Technology(Qingdao), Qingdao 266237, China
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| Abstract: |
| It has been recently found that the large-scale green tide of Ulva prolifera is originated in the southern part of the Yellow Sea. The biomass of U. prolifera increased rapidly during the process of northward drifting and attained their peak extent in Haizhou Bay (latitude around 35°N). During the migration of U. prolifera from south to north, they experienced a significant difference in temperature, DIN, and PO43--P concentrations. In this thesis, U. prolifera in the process of drifting was observed and the relationship between changes of environmental factors and biological characteristics of U. prolifera was analyzed. Results show that the values of photosystem Ⅱ (PSⅡ) maximum quantum yield Fv/Fm were reduced from 0.7 to 0.45, and values of PSⅡ actual quantum yield Y(Ⅱ) were reduced from 0.55 to 0.25; the mean nitrate reductase activity (NRA) was reduced from 2.7 to 0.5 μmol/L NO2-/(mg·h); and the mean reproductive allocation ratio (RA) was increased from 15% to 50%. Correlation analysis revealed significant relationship between DIN and biological characteristics of U. prolifera, indicating that DIN played an important biological role in the drifting. Temperature, light intensity, salinity, and PO43--P all significantly affected the photosynthetic activity and NRA of thalli, whereas these environmental factors showed no significant correlation with RA. Biological characteristics such as photosynthesis and nutrient absorption of U. prolifera were most sensitive to the changes of DIN in environment. Effects of other environmental factors on U. prolifera were, in descending order:temperature, PO43--P, salinity, and light intensity. Changes of environmental factors directly affected the growth and reproduction of U. prolifera during drifting to the north, especially to the Haizhou Bay (latitude around 35°N), the divide for morphology variation of U. prolifera. |
| Key words: Ulva prolifera environmental factors photosynthetic activity reproductive allocation ratio nitrate reductase activity |
