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Molecular phylogenetic analysis of attached Ulvaceae species and free-floating Enteromorpha from Qingdao coasts in 2007 总被引：3，自引：1，他引：2
Based on the sequence data of the nuclear ribosomal DNA internal transcribed spacer(ITS) 1,5.8 S,and ITS 2,the molecular phylogeny was analyzed on Ulvaceae species collected from Qingdao coasts in summer of 2007,including 15 attached Ulva and Enteromorpha samples from 10 locations and 10 free-floating Enteromorpha samples from seven locations.The result supported the monophyly of all free-floating Enteromorpha samples,implying the unialgal composition of the free-floating Enteromorpha,and the attached Ulvaceae species from Qingdao coasts were grouped into other five clades,suggesting that they were not the biogeographic origin of the free-floating Enteromorpha in that season. 相似文献
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不同pH海水和不同时间处理紫菜、石莼对呼吸强度和致死酸度试验结果表明,紫菜比石莼耐酸力强。在海水温度为18℃条件下,分别用pH_2、pH_3、pH_4、pH_5、pH_6、pH_7、pH_8处理,处理时间20分钟,紫菜除pH_2处理对呼吸强度有抑制作用和培养5天后有20％死亡外,pH_3、pH_4、pH_5、pH_6、pH_7、pH_8各组处理对呼吸强度都有促进作用,培养5天后没有死亡现象,而石莼经pH_2、pH_3处理,对呼吸强度都有抑制作用,培养5天后,pH_2处理组全部死亡,pH_3处理有50％死亡。pH_3和pH_4在海水温度为18℃条件下,处理时间为40分钟时,对紫菜呼吸强度有促进作用,培养5天报,pH_3处理组仅有20％死亡。而pH_3对石莼呼吸强度有抑制作用,培养5天后,全部灭亡。在生产上是否可以考虑用pH_3的海水处理紫菜网帘以达到消除石莼(杂藻)的目的,将是一项具有生产意义的待试验课题。 相似文献
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The aim of this study was to investigate the effects of light intensity and enhanced nitrogen supply on the growth and photosynthesis of the green-tide macroalga, Ulva prolifera. Thalli of U. prolifera were grown in natural or NH 4 +-enriched seawater under two different light intensities for 7 days, and then the growth rate, pigmentation, and photosynthetic performance of the thalli were evaluated. The results show that the relative growth rate(RGR) was markedly higher under the high light level than under the low light level. Enrichment with NH 4 + enhanced the RGR under high light intensity, but did not affect RGR under low light intensity. In low light conditions, NH 4 +-enrichment resulted in a marked decrease in the maximal photosynthetic rate( P m) and the maximum carbon fixation rate( V max), but it did not affect the half saturation constant for carbon( K 0.5) or the ratio of V max to K 0.5, which reflects the carbon acquisition efficiency. In high light conditions, P m, K 0.5, and the dark respiration rate( R d) increased under NH 4 + enrichment, but V max and the V max / K 0.5 ratio decreased. Regardless of the light intensity, NH 4 +-enrichment did not affect the apparent photosynthetic efficiency( α), which refl ects the ability of the alga to use light energy at low light levels. Under both low and high light intensities, the chlorophyll a(Chl a), chlorophyll b(Chl b), and carotenoids(Car) contents in thalli were higher in NH 4 +-enriched than in natural seawater, except that there was a decrease in the Chl b content of thalli in NH 4 +-enriched seawater under low light intensity. Therefore, NH 4 + enrichment improved the growth and photosynthetic performance of U. prolifera under high light intensity, but not under low light intensity. We discuss the possible mechanisms underlying these physiological responses. 相似文献
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在全球范围内广泛暴发的石莼属绿潮既包括大规模暴发的跨海域绿潮,也包括小规模暴发的局地绿潮。我国有关绿潮致灾物种的研究对象主要集中于黄海绿潮浒苔,而针对局地绿潮致灾物种的研究尚处于起步阶段。针对局地绿潮物种的鉴定和分布调查是有效预防和监测潜在大规模绿潮暴发的重要环节。本文对2020年11月初于山东烟台第一海水浴场暴发的石莼属绿潮进行了初步研究。经随机采样获得了12株藻体,根据tufA分子标记初步将其中11株鉴定为Ulvalaetevirens。本研究完成了U. laetevirens的一个代表性株系CNS00533的叶绿体基因组构建和解析。叶绿体基因组为110 889 bp,含有71个蛋白编码基因、27个tRNA基因和3个rRNA基因(rrl、rrn和rrn5)。烟台海域U.laetevirens株系叶绿体基因组基因组成和排列顺序与爱尔兰海域U.laetevirens株系MT179351完全一致,DNA序列相似性为99.8%,进一步证明CNS00533为U.laetevirens。此外,U.laetevirens的烟台株系与爱尔兰株系的叶绿体基因组也存在差异,烟台株系比爱尔兰株系多了5个I型内含子和1个II型内含子,导致叶绿体基因组长度增加7kb。CNS00533与U.rigidaMT179352叶绿体基因组之间存在多个不同的长片段插入序列(763—2 346 bp), DNA序列相似性也较低(93.1%);与U. australis MT179348相比差异更大,存在一个较大(覆盖45个基因)的基因组反转事件。在基于71个蛋白编码基因的遗传进化树中, CNS00533与U. laetevirens MT179351聚类在一枝,与U. rigida MT179352遗传距离较近,与U. australis MT179348的遗传距离很远,表明U. laetevirens、U. rigida和U. australis为石莼属的3个不同物种。2020年11月烟台海域局地绿潮事件的原因种U. laetevirens在我国近海绿潮事件中首次报道,本研究对该物种的分子进化分析将有助于对我国近海绿潮监测、物种鉴定提供数据支持和理论依据。 相似文献
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镉对石莼光合作用和呼吸作用及叶绿素含量的影响 总被引：1，自引：0，他引：1
实验表明 ,用含不同浓度镉 (0、5、10、15、2 0、2 5、30× 10 -6)的海水培养石莼 1～ 8d,石莼的光合作用、呼吸作用、叶绿素含量受到了明显的影响。 5× 10 -6的镉培养 3d,光合速率和叶绿素含量明显下降 ;培养时间越长 ,下降幅度越大。低浓度的镉 (5～ 10× 10 -6)对呼吸有促进作用 ,出现了“伤呼吸”;高浓度的镉 (>10× 10 -6)对呼吸有明显抑制作用 ,培养 5d后石莼开始死亡。 相似文献
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利用OJIP叶绿素a荧光评估干出对石莼(Ulva lactuca)光系统Ⅱ的影响 总被引：1，自引：0，他引：1
通过分析快速叶绿素a荧光动力学上升(荧光快相)和JIP-test的参数探讨了干出对石莼光系统II特征的影响。结果表明,起始荧光(Fo)随水分的丧失明显增加,在失水达到67%时快速叶绿素a荧光动力学曲线出现一个平台,即O-J-I-P上升转变为O-J上升(J=I=P)。随着水分丧失的增加,以单位反应中心为单位的天线色素吸收的能量(ABS/RC)和用于热耗散的能量(DIo/RC)增加,当失水达到67%时,ABS/RC和DIo/RC分别达到起始时的127.5%和225.4%;用于电子传递的能量(ETo/RC)并没有明显变化;而捕获的能量(TRo/RC)在失水超过31%时明显下降。干出导致最大光化学效率(φPo)、电子传递的量子产额(φEo)和捕获的激子能导致电子传递的效率(ψo)均明显下降,在失水达到67%时,与未失水相比分别下降24.5%、86.4%和89.8%。而在J点的叶绿素a相对荧光(VJ)随着水分的丧失明显升高,同时单位面积上激活的反应中心数量明显减少。以上结果表明干出对石莼光合作用PSII的影响主要是由于PSII反应中心的失活和PSII受体侧电子传递的抑制。 相似文献
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浒苔是研究生长、发育和环境适应性进化的最具吸引力的模式物种，也是食品、能源和高附加值化合物开发的潜在来源。浒苔的快速生长的特性使它们成为沿海生物地球化学循环的重要贡献者，但同时它们形成的绿潮和生物淤积也会造成严重的环境问题。到目前为止，石莼属中只有易变石莼（Ulva mutabilis）完成了基因组测序。为了进一步了解析石莼属绿藻的进化机制，我们分析了来自易变石莼U. mutabilis, 莱茵衣藻Chlamydomonas reinhardtii和团藻Volvox carteri三个物种的3905个单拷贝同源基因，最终在易变石莼中获得了63个受到正选择的同源基因。进一步的功能分析显示，这些正选择基因参与了光合作用、氨基酸和蛋白质合成、信号转导途径以及压力响应，这也为石莼属绿藻的快速生长及沿海环境适应性提供了证据。 相似文献
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Ulva species can grow rapidly in nutrient-rich habitats causing green tides and marine fouling. A more complete understanding of the reasons behind these outbreaks is urgently required. Accordingly, this study attempts to use microsatellite markers based expressed sequence tag（EST） to analyze the genetic variation of several Ulva prolifera populations in the South Yellow Sea of China. Two hundred and thirty-eight SSRs were identified from 8 179 unique ESTs（6 203 newly sequenced and 1 976 downloaded from NCBI database） and 37 primer pairs were successfully designed according to the ESTs; 11 pairs were selected to detect the genetic diversity and relationship of 69 attached U. prolifera samples and 13 free-floating samples collected from coastal and off-coast areas of the South Yellow Sea. The results of cross-species transferability showed that six of the 11 EST-SSR primers could give good amplification in other five Ulva species and the average allele number was 4.67. Genetic variation analysis indicated that all 82 U. prolifera samples were clearly divided and most samples collected from the same site clustered together as a group in the dendrogram tree produced by unweighted pair-group mean analysis（UPGMA） method and the cluster results showed some consistency with the geographical origins. In addition, 13 free-floating samples（except HT-001-2） were grouped as a single clade separated from the attached samples. 相似文献
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