993 resultados para 154-929E
Resumo:
麻黄属(Ephedra)起源较早,该属植物的形态性状极度退化或简化,可用于经典分类学的有价值的性状非常有限。分布于青藏高原的藏麻黄(E. saxatilis)和丽江麻黄(E. likiangensis)二者间形态相似,性状变异连续,很难分辨,但被《中国植物志》中、英文版作两个种处理。 本文对藏麻黄和丽江麻黄的七个居群、151个个体的叶、雌球花和节间长等形态学性状进行了分析,发现各性状的变异情况在群体间无明显差异。同时我们还对154个个体的叶绿体DNA trnT-trnF和 trnS-trnfM区进行了序列分析,两个片段的联合矩阵长1382bp,共有29个变异位点,其中有9个碱基变异和2个indel,可划分为H1、H2和H3三种单倍型。这3种单倍型在丽江麻黄中均有分布,但藏麻黄仅含H1和H2。 综合来自形态学和分子方面的证据,我们发现藏麻黄和丽江麻黄的关系非常近缘,因此建议予以合并。同时本文还以膜果麻黄(E. przewalskii)为外类群,从谱系生物地理学角度探讨了三种叶绿体单倍型的进化关系,发现H2最原始,分布最广;H1与其它两种单倍型间的序列差异较大,可能是较进化的类型。此外,无性克隆的繁殖方式可能是导致Ephedra单倍型非常简单的重要原因之一。
Resumo:
This report provides baseline biological data on fishes, corals and habitats in Coral and Fish Bays, St. John, USVI. A similar report with data on nutrients and contaminants in the same bays is planned to be completed in 2013. Data from NOAA’s long-term Caribbean Coral Reef Ecosystem Monitoring program was compiled to provide a baseline assessment of corals, fishes and habitats from 2001 to 2010, data needed to assess the impacts of erosion control projects installed from 2010 to 2011. The baseline data supplement other information collected as part of the USVI Watershed Stabilization Project, a project funded by the American Recovery and Reinvestment Act of 2009 and distributed through the NOAA Restoration Center, but uses data which is not within the scope of ARRA funded work. We present data on 16 ecological indicators of fishes, corals and habitats. These indicators were chosen because of their sensitivity to changes in water quality noted in the scientific literature (e.g., Rogers 1990, Larsen and Webb 2009). We report long-term averages and corresponding standard errors, plot annual averages, map indicator values and list inventories of coral and fish species identified among surveys. Similar data will be needed in the future to make rigorous comparisons and determine the magnitude of any impacts from watershed stabilization.
Resumo:
The Indo-Pacific lionfish, Pterois miles and P. volitans, have recently invaded the U.S. east coast and the Caribbean and pose a significant threat to native reef fish communities. Few studies have documented reproduction in pteroines from the Indo-Pacific. This study provides a description of oogenesis and spawn formation in P. miles and P. volitans collected from offshore waters of North Carolina, U.S.A and the Bahamas. Using histological and laboratory observations, we found no differences in reproductive biology between P. miles and P. volitans. These lionfish spawn buoyant eggs that are encased in a hollow mass of mucus produced by specialized secretory cells of the ovarian wall complex. Oocytes develop on highly vascularized peduncles with all oocyte stages present in the ovary of spawning females and the most mature oocytes placed terminally, near the ovarian lumen. Given these ovarian characteristics, these lionfish are asynchronous, indeterminate batch spawners and are thus capable of sustained reproduction throughout the year when conditions are suitable. This mode of reproduction could have contributed to the recent and rapid establishment of these lionfish in the northwestern Atlantic and Caribbean.
Resumo:
喀斯特环境是一类发育在可溶性碳酸盐类岩石上的环境系境,其生境具有高钙和干早等特征。喀斯特生境中的优势/特征植物也多具适应高钙、耐旱的特性。旋蒴苣苔(Boea hygrometrica)是喀斯特地区一种典型的抗旱和适应高钙的植物。本文在探讨了喀斯特地区植物适应高钙环境的不同方式的基础上,从旋蒴苣苔中克隆了两个受脱水和外源Ca2+诱导表达的基因,并对其表达调控和蛋白质产物进行了分析。本研究将为治理西南喀斯特地区日益退化的生态系统提供理论基础。 本文测定了贵州4个地区采集地内45种优势/常见种的地上部分和地下部分的全钙含量以及土壤的交换性钙含量。通过分析喀斯特地区植物与土壤钙含量的特征发现:喀斯特地区植物具有较高的钙含量平均值;土壤交换性钙含量对植物地上部钙含量的影响总体上不显著,对植物地下部钙含量的影响显著;不同类别的植物钙含量存在显著差异,蕨类植物地上部钙含量平均值明显低于被子植物;不同类别植物的钙的分布部位也存在显著差异,在蕨类植物和单子叶植物中地上部和地下部的钙含量相近,而双子叶植物的地上部钙含量明显高于地下部。根据地上部分与地下部分钙含量的差异性以及与土壤交换性钙含量的相关关系将其中14种优势植物对土壤高钙的适应方式分为3种类型:随遇型,高钙型和低钙型。随遇型植物地上部和地下部的钙含量均与土壤交换性钙含量成显著正相关关系;高钙型植物具有较强的钙富集能力,其地上部即使在低钙含量的土壤中也可维持较高的钙含量;低钙型植物的地上部即使在高钙的土壤中亦可维持较低的钙含量。对贵州和北京等地采集到的旋蒴苣苔钙含量和土壤含钙量的分析发现,其地上部和地下部钙含量即使在高钙土中也呈低水平,推测可能是通过控制根部对钙的吸收和向上运输来维持低钙水平。 从旋蒴苣苔cDNA 文库中筛选到两个片段,经5’RACE 得到cDNA 全长,分别命名为BhOMT1 和BhC2DP1。BhOMT1 编码一个包含359 个氨基酸的蛋白质,蛋白序列分析表明BhOMT1 为植物O-甲基转移酶。BhOMT1 基因组序列包含一个内含子,与其同源基因的基因结构相似。BhC2DP1 编码一个包含154 氨基酸的小分子蛋白质,内含一个C2 结构域,该结构域在很多植物蛋白中均存在。通过5’RAGE 的方法分别克隆了1465bp BhOMT1 启动子序列和1113bp 的BhC2DP1 启动子序列,分析发现其中均含有多种逆境胁迫诱导元件。通过对BhOMT1 和BhC2DP1 表达分析和Western 杂交发现这两个基因均受脱水和外源Ca2+的诱导表达,表明这两个基因可能参与了旋蒴苣苔的脱水保护和对高钙环境的适应。