| 摘要: |
| 持续降雨会引起光照强度和海水表层盐度的变化。近年来，受梅雨影响，福建省龙须菜（Gracilariopsis lemaneiformis）栽培产量波动明显。为揭示其原因，本实验设置3个盐度梯度（低盐: 16，中盐: 24，高盐: 32）和两个光强水平［低光: 30 μmol/(m2·s)，高光: 120 μmol/(m2·s)］，共6个不同处理组合，研究其对龙须菜生长和光合特性的影响。结果发现：①盐度、光照强度和二者交互作用对龙须菜的相对生长速率和净光合速率均具有显著影响（P<0.05），适当降低盐度、增加光照有利于提高藻体相对生长速率和净光合速率，同时盐度适当降低条件下藻体呼吸速率被显著抑制；②光照强度和盐度对龙须菜有效光合量子产率、最大相对电子传递速率、光能利用效率均具有显著影响（P<0.05），在光照增加条件下有效光合量子产率和最大相对电子传递速率随盐度增加呈先增加后降低的趋势，光照强度和盐度的交互作用仅对光能利用效率影响不显著（P>0.05）；③盐度对龙须菜的光合色素含量具有显著影响（P<0.05），在同一光强条件下藻体色素随着盐度增加呈先升高后降低的趋势；在盐度适当降低条件下，光照增加显著促进其叶绿素a的合成；盐度和光照强度的交互作用对龙须菜的叶绿素a和藻红蛋白含量具有显著影响（P<0.05）。进一步分析表明：光照充足条件下盐度的适当降低促进藻体光合作用的增强和光合色素合成，进而促进龙须菜的生长；当盐度过低时，龙须菜的生长、光合作用和色素合成均受到明显抑制。结果表明梅雨季节龙须菜栽培产量潜在地取决于光照强度、海水表层盐度及其耦合作用的变化。 |
| 关键词: 海洋生物学 龙须菜 光照强度 盐度 生长 光合特性 |
| DOI：10.3969/J.ISSN.2095-4972.20220322001 |
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| 基金项目:福建省科技特派员后补助项目；江苏海洋大学人才引进科研基金（KQ19068）；江苏海洋大学研究生科研与实践创新计划（KYCX2022-04）；江苏省优势学科建设工程；江苏省高等学校大学生创新创业训练计划（2020120068，2021120142）；连云港市“花果山英才计划”（KK21054） |
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| Effects of light intensity and salinity on the growth and photosynthetic performance of Gracilariopsis lemaneiformis |
| WANG Jinguo,CHEN Zeyu,SHI Mengqi,NI Jiaxuan,WU Hui,JIANG Shuying,HUANG Jingjing,WANG Jingwen,ZHOU Wei |
| (College of Marine Science and Fisheries, Jiangsu Ocean University, Jiangsu Key Laboratory of Marine Bioresources and Environment, Key Laboratory of Coastal Salt Marsh Ecosystems and Resources, MNR,CoInnovation Center of Jiangsu Marine Bioindustry Technology, Lianyungang 222005, China;Lianjiang Luoyuanwan Gold Medal Fishery Technology Co., Ltd., Fuzhou 350512, China) |
| Abstract: |
| Continuous rainfall has directly caused changes in light intensity and sea surface salinity. In recent years, the cultivated output of Gracilariopsis lemaneiformis in Fujian Province has fluctuated greatly effected by the rainy season. To reveal the mechanism, three salinity gradients (lower salinity, LS: 16; medium salinity, MS: 24; higher salinity, HS: 32) and two light intensity levels (lower light intensity, LL: 30 μmol/(m2·s); higher light intensity, HL: 120 μmol/ (m2·s)) were set to study the effects of 6 different treatment combinations on the growth and photosynthetic characteristics of G. lemaneiformis in this experiment. Results showed that firstly salinity, light intensity and their interaction had significant effects on the relative growth rates (RGR) and net photosynthetic rate (Pn) of G. Lemaneiformis (P<0.05). Appropriate reduction of salinity (MS) and increment of light (HL) were beneficial to the thalli RGR and Pn, while MS significantly inhibited respiratory rate (Pd). Secondly, light intensity and salinity had significant effects on effective quantum yield ［Y(II)］, maximum relative electron transfer rate (rETRmax), light energy utilization efficiency (α) and saturation irradiance (Ek) of G. Lemaneiformis (P<0.05). Under HL, Y(II) and rETRmax increased firstly and then decreased with increasing salinity. The interaction between light intensity and salinity had only insignificant effect on α (P>0.05). The last, salinity had a significant effect on the content of photosynthetic pigments of G. Lemaneiformis (P<0.05). Under the same illumination, the thalli pigments increased firstly and then decreased with the increase of salinity. Under MS, HL significantly promoted the synthesis of chlorophyll a, the interaction of salinity and light intensity had a significant effect on the chlorophyll a and phycoerythrin contents of G. Lemaneiformis (P<0.05). Further analysis showed that the appropriate reduction of salinity under sufficient light conditions promoted the algal photosynthesis and the synthesis of photosynthetic pigments, thereby promoting the growth of G. Lemaneiformis . When the salinity was too low (LS), the growth, photosynthesis and pigment synthesis of G. Lemaneiformis were significantly inhibited. Therefore, the cultivated output of G. Lemaneiformis in the rainy season may potentially depend on the changes of light intensity,sea surface salinity and their coupling effects. |
| Key words: marine biology Gracilariopsis lemaneiformis light intensity salinity growth photosynthesis performance |
