CAJ | 학술논문

以长江口及其邻近海域最重要的甲藻赤潮生物种东海原甲藻(Prorocentrum donghaiense Lu)为研究材料,观察其对氮、磷营养限制胁迫的耐受程度以及恢复营养条件下补偿生长的情况。研究实验分营养限制和恢复营养两个阶段进行,每个阶段均设置对照组、贫营养组、限氮组、限磷组和限氮限磷组。研究结果显示,在氮、磷营养限制胁迫下,东海原甲藻生长受到抑制,其中磷限制对藻细胞生长的抑制作用最小,氮磷共同限制的抑制作用最大。限磷组最大细胞密度为78×104 cell·mL–1,与对照组无显著差异(P>0.05),但显著高于其他处理组(P<0.05)。细胞各项生长参数和叶绿素a的含量,与细胞密度类似,其中限磷组的最大细胞日生长速率、最大平均相对生产率、最小细胞代时、最大叶绿素a含量分别为0.61 d–1、0.44 d–1、1.58 d和694.2μg·μL–1,与对照组无显著差异(P>0.05),而与其他处理组则有显著差异(P<0.05)。藻细胞所受到抑制作用随着培养时间的推移而加强。后期,限磷组和其他处理组的细胞密度均显著低于对照组(P<0.05),处理组各细胞参数均显著劣于对照组(P<0.05)。在恢复营养的培养前期,4个经过营养限制处理组的生长情况均显著优于持续营养正常条件下培养的对照组(P<0.05)。表明东海原甲藻细胞表现出较强的超补偿生长能力,其中磷限制后表现出的超补偿能力最强。由此可知,东海原甲藻补偿生长的主要特征表现为,在恢复营养培养后,各处理组比对照组细胞数增多,叶绿素a含量增高,细胞日生长速率和平均相对生长率提高,细胞数净增率高达10.30%~80.95%,细胞代时缩短。根据研究结果认为,东海原甲藻具有较强的耐受低磷能力,而在营养条件恢复情况下,经历低磷胁迫的东海原甲藻又具有最强超补偿生长能力,使得其在与硅藻竞争中居于优势,这是东海原甲藻赤潮在中国沿海海域频繁暴发的原因之一。本研究旨在为揭示长江口及其邻近的东海海域甲藻赤潮逐年大规模暴发机理以及硅藻与甲藻赤潮种的演替现象提供依据。以長江口及其鄰近海域最重要的甲藻赤潮生物種東海原甲藻(Prorocentrum donghaiense Lu)為研究材料,觀察其對氮、燐營養限製脅迫的耐受程度以及恢複營養條件下補償生長的情況。研究實驗分營養限製和恢複營養兩箇階段進行,每箇階段均設置對照組、貧營養組、限氮組、限燐組和限氮限燐組。研究結果顯示,在氮、燐營養限製脅迫下,東海原甲藻生長受到抑製,其中燐限製對藻細胞生長的抑製作用最小,氮燐共同限製的抑製作用最大。限燐組最大細胞密度為78×104 cell·mL–1,與對照組無顯著差異(P>0.05),但顯著高于其他處理組(P<0.05)。細胞各項生長參數和葉綠素a的含量,與細胞密度類似,其中限燐組的最大細胞日生長速率、最大平均相對生產率、最小細胞代時、最大葉綠素a含量分彆為0.61 d–1、0.44 d–1、1.58 d和694.2μg·μL–1,與對照組無顯著差異(P>0.05),而與其他處理組則有顯著差異(P<0.05)。藻細胞所受到抑製作用隨著培養時間的推移而加彊。後期,限燐組和其他處理組的細胞密度均顯著低于對照組(P<0.05),處理組各細胞參數均顯著劣于對照組(P<0.05)。在恢複營養的培養前期,4箇經過營養限製處理組的生長情況均顯著優于持續營養正常條件下培養的對照組(P<0.05)。錶明東海原甲藻細胞錶現齣較彊的超補償生長能力,其中燐限製後錶現齣的超補償能力最彊。由此可知,東海原甲藻補償生長的主要特徵錶現為,在恢複營養培養後,各處理組比對照組細胞數增多,葉綠素a含量增高,細胞日生長速率和平均相對生長率提高,細胞數淨增率高達10.30%~80.95%,細胞代時縮短。根據研究結果認為,東海原甲藻具有較彊的耐受低燐能力,而在營養條件恢複情況下,經歷低燐脅迫的東海原甲藻又具有最彊超補償生長能力,使得其在與硅藻競爭中居于優勢,這是東海原甲藻赤潮在中國沿海海域頻繁暴髮的原因之一。本研究旨在為揭示長江口及其鄰近的東海海域甲藻赤潮逐年大規模暴髮機理以及硅藻與甲藻赤潮種的縯替現象提供依據。
이장강구급기린근해역최중요적갑조적조생물충동해원갑조(Prorocentrum donghaiense Lu)위연구재료,관찰기대담、린영양한제협박적내수정도이급회복영양조건하보상생장적정황。연구실험분영양한제화회복영양량개계단진행,매개계단균설치대조조、빈영양조、한담조、한린조화한담한린조。연구결과현시,재담、린영양한제협박하,동해원갑조생장수도억제,기중린한제대조세포생장적억제작용최소,담린공동한제적억제작용최대。한린조최대세포밀도위78×104 cell·mL–1,여대조조무현저차이(P>0.05),단현저고우기타처리조(P<0.05)。세포각항생장삼수화협록소a적함량,여세포밀도유사,기중한린조적최대세포일생장속솔、최대평균상대생산솔、최소세포대시、최대협록소a함량분별위0.61 d–1、0.44 d–1、1.58 d화694.2μg·μL–1,여대조조무현저차이(P>0.05),이여기타처리조칙유현저차이(P<0.05)。조세포소수도억제작용수착배양시간적추이이가강。후기,한린조화기타처리조적세포밀도균현저저우대조조(P<0.05),처리조각세포삼수균현저렬우대조조(P<0.05)。재회복영양적배양전기,4개경과영양한제처리조적생장정황균현저우우지속영양정상조건하배양적대조조(P<0.05)。표명동해원갑조세포표현출교강적초보상생장능력,기중린한제후표현출적초보상능력최강。유차가지,동해원갑조보상생장적주요특정표현위,재회복영양배양후,각처리조비대조조세포수증다,협록소a함량증고,세포일생장속솔화평균상대생장솔제고,세포수정증솔고체10.30%~80.95%,세포대시축단。근거연구결과인위,동해원갑조구유교강적내수저린능력,이재영양조건회복정황하,경력저린협박적동해원갑조우구유최강초보상생장능력,사득기재여규조경쟁중거우우세,저시동해원갑조적조재중국연해해역빈번폭발적원인지일。본연구지재위게시장강구급기린근적동해해역갑조적조축년대규모폭발궤리이급규조여갑조적조충적연체현상제공의거。
Variation in tolerance of Prorocentrum donghaiense Lu to N or P deficiency, and its compensatory growth under normal nutrient conditions (f/2 culture media) were studied. Two experimental treatments that included a nutrient deficiency period and a period without nutrient stress, were conducted. First, P. donghaiense was cultured for 10 days under nutrient stress that included, poor nutrients, N deficiency, P deficiency, and N plus P deficiency, while normal nutrient conditions (f/2 culture media) served as a control. Second, nutrient stress was removed, and the treated and control groups were cultured for another ten days at the same inoculation density and a sufficient nutrient supply, si-multaneously. Cell density, growth rate, relative growth rate, generation time and Chlorophyll-a was determined during the two periods. The results indicated that nutrient stress has an inhibitory effect on cell growth. Phosphorus deficiency had the least inhibitory effect, whereas N plus P deficiency had a comparatively large inhibitory effect. There was a significant difference (P<0.05) in the growth condition of algal cells between the treated and control groups. Maximum cell densities of the control, poor nutrients, N deficiency, P deficiency, and N plus P deficiency groups were 83×104 cell·mL–1, 32×104 cell·mL–1, 43×104 cell·mL–1, 78×104 cell·mL–1 and 29×104 cell·mL–1, respectively. Maximum growth rates were 0.64 d–1, 0.53 d–1, 0.61 d–1, 0.54 d–1and 0.51 d–1;maximum average relative growth rates were 0.61 d–1, 0.39 d–1, 0.44 d–1, 0.44 d–1and 0.35 d–1;minimum generation times were 1.13 d, 1.76 d, 1.58 d, 1.58 d and 2.00 d, and maximum chlorophyll-content a was 723.7μg·μL–1, 286.4μg·μL–1, 427.1μg·μL–1, 694.2μg·μL–1 and 292.9μg·μL–1, respectively. During the periods when nutrient stress was removed, it was found that after being subjected to nutrient stress, P. donghaiense had the ability of compensatory growth, particularly in the P deficiency treatment. There was a significant difference (P<0.05) in the growth condition of algal cells between the treated and the control groups. The main charac-teristic of compensatory growth of P. donghaiense was that the treated group had a higher average relative growth rate, a greater number of cells, and higher chlorophyll-a content than the control group in the initial culture time. In addition, the maximal rate range of net cell increase was 0.30%–80.95%, and the generation time of the cells was shorter. As the culture time proceeded, the difference between the treated group and the control group decreased. Eventually, all para-meters of the treated and control groups were similar. These results showed that P. donghaiense has over-compensatory growth under conditions of nutrient stress, particularly during P deficiency. This might be the cause of harmful algal blooms in the China Seas, which are P deficient year-round.