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11.
Sargassum horneri is a common brown macro-alga that is found in the inter-tidal ecosystems of China. To investigate the current status of seaweed resources and provide basic data for its sustainable development, ISSR (inter simple sequence repeat) and SRAP (sequence related amplified polymorphism) markers were used to analyze the population genetics among nine natural populations of S. horneri. The nine studied populations were distributed over 2 000 km from northeast to south China. The percentage of polymorphic loci P% (ISSR, 99.44%; SRAP, 100.00%), Nei’s genetic diversity H (ISSR, 0.107-0.199; SRAP, 0.100-0.153), and Shannon’s information index I (ISSR, 0.157-0.291; SRAP, 0.148-0.219) indicated a fair amount of genetic variability among the nine populations. Moreover, the high degree of gene differentiation G st (ISSR, 0.654; SRAP, 0.718) and low gene flow N m (ISSR, 0.265; SRAP, 0.196) implied that there was significant among-population differentiation, possibly as a result of habitat fragmentation. The matrices of genetic distances and fixation indices (F st ) among the populations correlated well with their geographical distribution (Mantel test R=0.541 5, 0.541 8; P=0.005 0, 0.002 0 and R=0.728 6, 0.641 2; P=0.001 0, 0.001 0, respectively); the Rongcheng population in the Shandong peninsula was the only exception. Overall, the genetic differentiation agreed with the geographic isolation. The fair amount of genetic diversity that was revealed in the S. horneri populations in China indicated that the seaweed resources had not been seriously affected by external factors. 相似文献
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外来囊藻(Colpomeniaperegrina)是一种在潮间带分布广泛的褐藻,它能附着在牡蛎壳上进行跨海区扩散,因而是研究生物多样性变动和生物地理格局形成的良好模型。外来囊藻在中国沿海虽有分布,但关于其种群遗传多样性和分化研究的报道尚为空白。本研究采集了中国近海13个外来囊藻种群样本。通过扩增301条线粒体cox3序列,发现了26个单倍型;通过重建单倍型网络图和基于最大似然法与贝叶斯法重建系统进化树,发现外来囊藻种内遗传多样性较高, 13个种群划分为3个遗传世系,其中浙江南麂列岛的7个种群组成遗传世系A,辽宁和山东的样本则分化为遗传世系B和C。中国近海外来囊藻的这种种群遗传结构可能源于更新世末次盛冰期黄渤海、东海边缘海的环境变化和海平面的大幅下降。遗传世系A具有的较高单倍型多样性,其原因可能是南麂列岛独特的地理位置和潮间带环境的共同作用。 相似文献
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测定了角叉菜属(Chondrus)5个代表种的核糖体DNA内转录间隔区(ITS)及5.8SrDNA基因序列。结果表明,角叉菜属ITS区(含ITS1、5.8SrDNA和ITS2)序列长度范围为704—714bp,G+C含量为44.6%—45.7%,变异位点69个,信息位点16个;其中,ITS1和ITS2的长度范围分别为147—149bp和398—404bp。5.8SrDNA长度为158bp,没有变异和信息位点。由MEGA3构建的系统进化树(ME和MP)显示:在进化尺度上,真红藻纲的松节藻科(Rhodomelaceae)与红毛菜纲(Bangiophyceae)亲缘关系较近。在真红藻纲内,杉藻目(Gigartinales)的进化地位相对较高,其次是海膜科(Halymeniaceae)、石花菜科(Gelidiaceae)、红叶藻科(Delesseriaceae)和粉枝藻科(Liagoraceae)等,而松节藻科进化地位相对较低。在杉藻目内,杉藻科(Gigartinaceae)和胶黏藻科(Dumontiaceae)进化关系密切,而形态学特征相似的角叉菜和马泽藻(Mazzaella)亲缘关系非常近。 相似文献
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Formation and early development of tetraspores of Polysiphonia urceolata （Rhodomelaceae, Rhodophyta）
Polysiphonia urceolata is one type of potential commercial red seaweeds used for breeding and cultivation, because of its significant biochemical
and biomedical application. However, the information of breeding and seedling incubation for cultivation is limited, especially
the early development. In this study, tetrasporohyte and gametophyte of P. urceolata were taken as the study materials in Huiquan Bay, Qingdao, China. The cleaned and sterilized tetrasporophytes and gametophytes
were pre-cultured in sterilized seawater, then nurtured at 18°C, 25 μmol photons m−2 s−1 in 12:12 h (light:dark) photoperiod. Continuous observation under microscope showed that the early development consists of
bipolar division stage and seedling stage. In the division stage, tetraspores germinate into bipolar sporelings that further
differentiate into a colorless rhizoidal portion and a lightly pigmented upright shoot. The lightly pigmented rhizoidal cell
develops to a rhizoid and the larger pigmented cell transforms to an erect axis. In the seedling stage, several quasi-protuberances
appear on the erect axis and form juvenile seedlings. The results demonstrate the culture of P. urceolata from tetraspores under laboratory conditions.
Supported by National Key Technology Support Program, Development Program of China (No.2006AA09Z21), National Natural Science
Foundation of China (No. 40618001 and N_CUHK438/06) and Shandong Agricultural Seed Stock Breeding Project 相似文献
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潮间带红藻海萝(Gloiopeltis furcata)对失水胁迫具有很强的耐受能力。为探索海萝周期性失水过程中的响应机制,本研究在24 h内设计了两次连续的失水-复水循环处理,测定了海萝抗氧化酶活力的变化情况。同时,利用转录组测序技术,结合荧光定量PCR方法(qRT-RCR),对海萝失水响应基因的转录表达进行了验证。结果表明:海萝转录组共组装到32681条基因。与对照组相比,处理组共表达了7161条差异表达基因(differentially expressed genes, DEGs)。KEGG分析显示, DEGs分布在代谢、环境信息加工、有机体系统、遗传信息加工、细胞进程等方面。海萝抗氧化酶活力测定发现,抗氧化能力对海萝响应失水胁迫十分重要。过氧化氢酶(CAT)、硫氧还蛋白还原酶(TrxR)、超氧化物歧化酶(SOD)参与抗氧化过程,其中CAT酶活力对海萝抵抗失水胁迫尤为重要。此外,qRT-PCR结果显示,海萝中渗透调节物质红藻糖苷合成的相关基因(GfUGPase、GfGK、GfGPDH)只对初次失水处理有正响应。而热激蛋白70基因(GfHSP70)、碳酸酐酶基因(GfCA)、MYB蛋白编码基因(GfMYB)以及谷胱甘肽S转移酶基因(GfGST)在两次失水过程中其转录水平均有上调表达,它们也参与了海萝失水响应机制。 相似文献
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华南伊迪卡拉纪"庙河生物群"的属性分析 总被引：4，自引：0，他引：4
我国南方伊迪卡拉(震旦)系陡山沱组页岩中,保存了以"庙河生物群"为代表的宏体碳质压膜化石群,以大量底栖固着的多细胞藻类为主,还包含推测的后生动物和海绵动物、可疑的遗迹化石等多门类生物化石,化石类型多样、分异显著,代表着新元古代"雪球"冰期之后和寒武纪早期后生动物大爆发前夕地球早期多细胞生物的一次大规模的进化辐射事件。本文通过比较湖北秭归庙河和贵州江口翁会两个典型产地的宏体化石优势属种的形态特征,以及两地所处的沉积古环境,分析探讨了这些优势类别与现生多细胞生物(包括红藻、褐藻和绿藻三大高级藻类)的亲缘关系。研究表明,寒武纪之前大约35~10Ma间,各门类多细胞藻类广泛发育,与后生动物的先驱分子构成独特的古生态群落。 相似文献
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Artificial seedling production of Sargassum thunbergii is an effective way to relieve pressure on natural resources. In order to improve the utilization of zygotes and reduce the loss of seedlings, studies on the characteristic of the zygotes release, the development of rhizoids, the attachment of germlings, and the influence of jet washing were conducted. Results show that the percent of zygotes released was increased with time in the first 60 h. The capacity of germlings attached to the substratum was significantly increased, especially coincident with the time of the new rhizoids emerged and elongated. The detachment rate of germlings significantly decreased with the delay of starting time of jet washing or the reduction of jet washing velocity. However, the jet washing at any level applied in the experiment could cause considerable loss of germlings within the 20 days after the attachment. Our study provided some parameters to optimize the operation in the early stage of seedling production. 相似文献
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We conducted a phenological evaluation of Sargassum thunbergii, a common algal species, along the coast of Lidao Bay, Rongcheng, China. The local S. thunbergii population entered a maturation period from early June to mid-August, when seawater temperature was 14.4 to 25.1°C. Our results suggest an increase in temperature and day length during this period initiated thalli maturation. Inhabitants of the low tidal zone had higher thalli length and biomass compared with those from the mid-and high tidal zones. We observed a switch in the length frequency distribution and contribution of length classes to biomass between the small (<20 cm) and long (20–79.9 cm) length classes at the time of thallus maturity. This suggests there is a trade-offbetween sexual reproduction and vegetative regeneration. 相似文献
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遗传标记经历了形态标记、细胞学标记、蛋白质标记及DNA标记的四个重要发展历程。纵观遗传学的发展历史,遗传学的发展推动了新型遗传标记的发展,每一种新型遗传标记的发现,均推进了遗传理论与技术的发展。19世纪后期,孟德尔以豌豆为材料,利用7对形态学标记对杂种后代的不同个体依据性状表现进行归类分析,发现了著名的遗传分离规律和独立分配规律。细胞学标记是指能明确显示遗传多态性的细胞学特征,如染色体形态、数目和结构在不同物种中的差异等,可以作为一种遗传标记来进行基因定位。20世纪50年代,人们发现同工酶是一种可用于物种起源与进化研究、种质鉴定、分类等诸多领域的分子标记技术(Markert et al.,1959)20世纪后期以来,DNA分子标记技术不断涌现,相继建立了RFLP(restriction fragment lengthen polymorphisis)、DNA指纹 (DNA fingerprint)，RAPD (random anplified polymophism DNA), AFLP(amplified fragnent lengthen polynorphisn)、微卫星 DNA (microsate llite DNA).SNP(single nucleotide polymorphisn)等专门的技术，在生物研究中得以广泛应用。分子标记技术应用于藻类学研究较晚,主要用于藻类的系统发生、地理分布、种群遗传、分类、亲本鉴定、杂种优势的鉴别及种质鉴定等领域。 相似文献