城市特定生境下土壤动物的生态分布

通过对2002年9月至2003年3月间上海3种生境类型下土壤动物的调查,共捕获土壤动物3863个,属27个类群,其中绿地中的类群数和个体数多于农田和废弃地。农田中的优势类群为弹尾类(collembola)和蚯蚓类(Oligchaeta);废弃地中的优势类群为线虫类(Nematoda)、双翅类幼虫(Diptera(L))、螨类(Acarina)和弹尾类(Collembola);绿地中的优势类群为线蚓类(Enchytraeidae)和弹尾类(Collembola)。绿地中的优势类群为农田和绿地中的Simpson,优势度指数除12月外均高于废弃地,与Pielou均匀性指数相反,但Shannon-Wiener多样性指数规律不明显。土壤动物的数量和种类在10月份最多,随天气转冷而减少,绿地和废弃地中土壤动物个体数于次年3月份逐渐增多,农田中的于次年1月逐渐增多。表聚性显著,Ⅰ层(0～5cm)最多,Ⅱ(5～10cm)、Ⅲ(10～15cm)两层差异不大。     

Chorionic villus culture for prenatal diagnosis of chromosome defects: Reduction of the long-term cultivation time

We report in detail two series of chorionic villus cultivation for prenatal chromosomal diagnosis. Chorionic villi were sampled from both first- and second-trimester pregnancies. One hundred cultures were treated with trypsin–EDTA for 2 h and collagenase overnight, (method A) and 100 were treated with trypsin–EDTA for 1 h and collagenase for 2 h (method B). Using short-term enzymatic digestion, the cultivation time was reduced from 14 days to 6 days. Sufficient amounts of metaphases of good quality were present in 93 per cent of primary cultures harvested in situ, whereas enough metaphases of sufficiently good quality were in most cases present only after subcultivation of the cultures using method A. The decrease in cultivation time obtained is probably due to a higher yield of viable cells in monocellular suspension, an increased attachment efficiency, and a more rapid attachment of single cells (within 24 h).     

中国主要类型土壤Cd、Pb、Cu和As的主要生态学指标和临界含量

通过对中国主要类型土壤中Cd、Cu、Pb、As的生态效应和环境影响以及多指标、多体系确定土壤元素临界含量的研究,提出了中国主要类型土壤Cd、Cu、Pb、As的临界含量及其系统分类特征.     

Analysis and improving ways for water condition in winter wheat field of dryland in subhumid areas of the loess plateau

Based on the soil moisture data from the locating experiments from 1986-1990, and using the water balance method, the water supply and demand state in the field of winter wheat, and the ways for improving water condition in dryland of subhumid by dry area of the Loess Plateau were studied. The results suggested that a low precipitation satisfying ratio of 42.9%-58.8% appears in the growing period of winter wheat, and the yield, to a great extent depends on the water that was stored in deep soil layer in the previous rainy season. The filed trial results showed that tillage in the summer fallow period,straw cover, soil moisture regulation with adequate fertilization, crop rotation and proper croppingsystem could be the efficient ways for improving the water condition,and for the exploitation and utilization of natural water resources(both precipitation and soil water) in the winter wheat field of dryland.     

Maternal sex chromosome mosaicism diagnosed by amniocentesis and percutaneous umbilical cord sampling

We present a remarkable chain of events in which percutaneous umbilical cord sampling was performed in an attempt to clarify a situation of possible fetal sex chromosome mosaicism in an amniotic fluid culture and led to the discovery that the mother herself had a 45,X/46,XX/ 47.XXX chromosome constitution. This may have simply represented the chance concurrence of pseudo-mosaicism in the amniotic fluid culture of a woman with an abnormal sex chromosome constitution, but it is also possible that the 45,X colony was maternal in origin. Although clearly a most unusual circumstance, the possibility should be kept in mind when termination of a pregnancy is being considered because of apparent mosaicism in a prenatal diagnostic study.     

西昆仑山区土壤垂直带谱

西昆仑山区位于青藏高原西北隅,高山深谷,原面广阔,地形复杂,气候多样,致使本区土壤垂直带谱类型众多,概分为极干旱、干旱、半干旱和高寒干旱、高寒半干旱5个类型。其中干旱和半干旱型土壤垂直带谱中广布着草原和草甸草原,是塔里木盆地南缘重要的天然牧场。特别是半干旱型中还有云杉林分布,是昆仑山系唯一森林分布区。 本区土壤垂直带谱在边缘山脉与内部山脉之间,低海拔山地与耸立在5000m左右高原面上的高海拔山地之间有明显的差别。     

土壤中多环芳烃化合物的生物降解及监测

在实验室模拟条件下,研究芳香化合物菲污染土壤中的生物降解作用。结果表明,转基因工程菌对土壤中菲的生物降解有很好促进效果,在30d内约有50%的菲被降解。同时利用分子生物学技术对污染环境中转基因工程菌进行了追踪监测,发现添加菌的数量随时间的推移逐渐减少。     

地球环境中的放射性污染

地球环境中的放射性污染有天然辐射来源和人为放射性来源,通过消化道、呼吸道和皮肤、粘膜或伤口进入人体内,对人体形成直接损伤、间接损伤和远期辐射效应,应从内照射和外照射防护两个方面来防止环境中的放射性污染.     

Effect of long-term fertilization on soil nitrate distribution

ＩｎｔｒｏｄｕｃｔｉｏｎＦｅｒｔｉｌｉｚａｔｉｏｎｉｓｅｓｓｅｎｔｉａｌｆｏｒａｇｒｉｃｕｌｔｕｒａｌｐｒｏｄｕｃｔｉｏｎ ,ｂｕｔｕｎｒｅａｓｏｎａｂｌｙａｐｐｌｙｉｎｇｆｅｒｔｉｌｉｚｅｒｓｃｏｕｌｄｒｅｓｕｌｔｉｎｓｅｒｉｅｓｏｆｐｒｏｂｌｅｍｓｓｕｃｈａｓｃｒｏｐｑｕａｌｉｔｙｄｅｃｌｉｎｅ,ｆｅｒｔｉｌｉｚｅｒｕｓｅｅｆｆｉｃｉｅｎｃｙｄｅｃｒｅａｓｅ,ｒｅｓｉｄｕａｌｆｅｒｔｉｌｉｚｅｒｓｐｏｌｌｕｔｉｏｎ ｇｒｏｕｎｄｗａｔｅｒａｎｄｒｉｖｅｒｓａｎｄｎｉｔｒｏｇｅｎｃｏｎｔｅｎｔｅｄ …