Description of a new species of Triplophysa (Teleostei: Nemacheilidae) from Guizhou Province,China

A new cave‐dwelling fish species Triplophysa guizhouensis is described based on specimens collected from Guizhou, China, in a subterranean system interconnected with the Hongshui River drainage. The species can be distinguished from its congeners by a combination of characters: eyes present; caudal fin with 14 branched rays; inner gill rakers of first gill arch 8–10; posterior chamber of air bladder developed; and body posterior of dorsal fin scaled. A key to species of Triplophysa in the Pearl River basin is provided.     

珠江下游颗粒沟链藻Aulacoseira granulata (Ehrenberg) Simonsen及形态相近种赫组基沟链藻Aulacoseira herzogii (Lemmerman) Simonsen的形态学研究

采用扫描电镜(SEM)技术,对采自珠江下游的沟链藻属2个物种颗粒沟链藻Aulacoseira granulata(Ehrenberg)Simonsen和赫组基沟链藻A.herzogii(Lemmerman)Simonsen的形态特征进行了观察和描述,并与其他相近种的形态异同点进行了比较分析。     

珠江三角洲城市群生态安全保障技术研究

近年来,在工业化、城镇化迅速推进和人口急剧增长的同时,珠三角城市群正面临严重的现代城市生态问题。生态安全问题已成为珠三角地区率先全面建成小康社会的重大制约瓶颈,对该地区经济社会的可持续发展构成了严重的威胁。"珠江三角洲城市群生态安全保障技术"项目将围绕脆弱生态修复与保护这一科技需求,对珠三角城市群复合生态系统进行综合研究。项目将针对内部互动复杂、空间组织紧凑、经济关联密切的城市群复合生态系统,开展城市群生态基底核算与健康诊断、城市群代谢模拟与生态风险预测预警技术、城市群生态安全格局网络设计及生态安全保障技术、城市群生态景观重建与生态空间修复技术、濒海城市群受损生境修复与生态安全保障技术以及城市群生态安全调控技术集成及协同监管平台构建与示范等六方面的研究。项目将为珠三角城市群生态问题的识别、评估与调控提供有效的理论基础、方法体系及技术示范,由之将为保障该城市群的生态安全提供科学支持,并带来显著的社会、经济与生态效益。     

合浦珠母贝的配子发生

本文研究了合浦珠母贝精子和卵子的发生过程,详细描述了原始生殖细胞,精原细胞,卵原细胞,精母细胞,卵母细胞以及精子和卵子的形态结构;另外还报道了合浦珠母贝中独特的精、卵退化现象,并讨论了它们对合浦珠母贝人工育苗生产的影响。     

Trisomic categories in pearl millet (Pennisetum americanum (L.) Leeke)

Summary In pearl millet [Pennisetum americanum (L.) Leeke], in the open pollinated and crossed progenies of autotriploids, desynaptics and translocation heterozygotes, two primary trisomics, one each of secondary and tertiary trisomics, two primary trisomics with interchanges, two interchange secondary trisomics, and three interchange tertiary trisomics were located. These categories were determined on the basis of chromosomal associations formed at meiosis. In one other trisomic, its category, whether tertiary or interchange trisomy, could not be determined. Some of these categories, like the secondary trisomy and interchange tertiary trisomy, are reported for the first time.     

Host plant resistance to grain mould in germplasm accessions of pearl millet (Pennisetum glaucum [L.] R. Br.)

Abstract

The paucity of information on the moulds in Indian pearl millet (Pennisetum glaucum) led to the studies that were conducted at ICRISAT, India to evaluate (a) 447 germplasm accessions of 32 countries for mould reaction in rainy season, (b) threshed grain mould rating (TGMS) and mycoflora on grains of each accession, and (c) mould scores in field and in vitro. Post physiological maturity evaluation showed that 16% of the accessions secured a mould rating of 2. In TGMS, 18% were mould free and 57% secured a rating of 2 on a 1 – 9 scale. Assessment of twenty representative accessions in vitro against individual and mixed conidial suspensions (1 × 10⁽⁶⁾ conidia ml^(?1)) of Fusarium moniliforme, F. pallidoroseum and Curvularia pennisetti indicated significant correlation (r = 0.97) between the overall field and in vitro scores of mixed spores inoculations. The mycoflora for TGMS in blotter test revealed that Fusarium moniliforme, F. pallidoroseum, Curvularia pennisetti, Helminthosporium spp., Alternaria spp. and Colletotrichum spp. to be the major fungi affecting pearl millet grain. It is advisable to harvest panicles at the physiological maturity stage to obtain better quality grains. A strong negative correlation between TGMS and % GS (r = 0.4601) and positive correlation between TGMS and % UGS (r = 0.4654) indicated that, the lesser the threshed grain mould rating higher the % seed germination.     

Pearl Formation: Persistence of the Graft During the Entire Process of Biomineralization

Most bivalves species of the genus Pinctada are well known throughout the world for production of white or black pearls of high commercial value. For cultured pearl production, a mantle allograft from a donor is implanted into the gonad of a recipient oyster, together with a small inorganic bead. Because of the dedifferentiation of cells during the first steps of the host oyster's immunological reaction, so far the fate of the graft and its exact role in the process of pearl formation could not be determined via classical histological methods. Here we report the first molecular evidence of the resilience of the graft in the recipient organism by showing that cells containing genome from the donor are still present at the end of pearl formation. These results suggest the existence of a unique biological cooperation leading to the successful biomineralization process of nacreous secretion in pearl formation.     

珠江口水域夏季小型底栖生物群落结构

于2010年8月在珠江口水域进行小型底栖生物取样分析,结果表明,该调查水域夏季小型底栖生物的平均丰度为(183±174)个/10 cm2,平均生物量为(345±334)μg干重/10 cm2,平均生产量为(3104±3008)μg干重/10 cm2。共鉴定出小型底栖生物16个类群,按丰度,自由生活海洋线虫和双壳类幼体为优势类群,其丰度分别占调查水域小型底栖生物总丰度的62.61%和22.62%。按生物量,优势类群由双壳类幼体(50.57%)、线虫(13.33%)和多毛类(12.47%)等组成。81.15%的小型底栖生物分布在0—5 cm的沉积物中。与环境因子相关分析表明:小型底栖生物丰度、线虫丰度与温度呈显著负相关,与盐度呈显著正相关。调查水域线虫与桡足类数量的比值(N/C)呈现出由河口上游向下游递增,且西岸明显高于东岸的趋势。     

2010年夏季珠江口海域颗粒有机碳的分布特征及其来源

于2010年8月对珠江口海域20个站位的颗粒有机碳(POC)进行采样,分析了POC的空间分布特征,讨论了POC与环境因子之间的关系,并利用碳稳定同位素(δ13C)分析了POC的来源及其贡献率。结果显示,研究区域POC的浓度范围98.5—1929.8μg/L,平均浓度541.9μg/L,空间分布总体呈现自北部海域向中部海域逐渐降低,中部海域至南部海域又逐渐升高,底层大于表层的特点。总悬浮颗粒物、叶绿素a、水动力是影响POC空间分布的重要原因。研究区域总悬浮颗粒物δ13C值的变化范围-27.05‰—-21.03‰,平均为-24.57‰,反映出珠江口海域颗粒有机碳为陆源和水生源混合来源,其分布呈现沿盐度梯度自口门内向口门外逐渐递增,底层高于表层的特点。陆源输入和海洋生物生产是影响δ13C值分布的主要原因。运用二元混合模型计算得知,珠江口北部和中部海域POC以陆源有机碳为主,贡献率平均为64%;南部海域POC以水生源有机碳为主,贡献率平均为68%。与20多年前相比,POC的分布特征与来源已经发生了改变,珠江口海域含沙量减少与营养盐含量增加可能是导致POC组成发生变化的主要原因。