两种吡虫啉种衣剂在棉花和土壤中的残留动态研究

采用田间试验方法，研究了两种吡虫啉种衣剂在棉花和土壤中的残留消解动态，并对其在棉花上使用的安全性作出了评价。结果表明，两种吡虫啉种衣剂无论在棉株中或土壤中消解动态没有显著差异，其消解速度相当缓慢，有较长的药效。试验还表明，无论是推荐药量还是加倍药量．在正常使用条件下，都不会造成棉子残毒污染和土壤的残留积累。     

The last deglaciation event in the eastern central arctic ocean

Oxygen isotope records of cores from the central Arctic Ocean yield evidence for a major influx of meltwater at the beginning of the last deglaciation 15.7 thousand years ago (16,650 calendar years B.C.). The almost parallel trends of the isotope records from the Arctic Ocean, the Fram Strait, and the east Greenland continental margin suggest contemporaneous variations of the Eurasian Arctic and Greenland (Laurentide) ice sheets or increased export of low-saline waters from the Arctic within the East Greenland Current during the last deglaciation. On the basis of isotope and carbon data, the modern surface- and deep-water characteristics and seasonally open-ice conditions with increased surface-water productivity were established in the central Arctic at the end of Termination lb about 7.2 thousand years ago or 6,000 calendar years B.C.).     

Late quaternary environmental history of lake valencia, Venezuela

Chemical, paleontological, and mineralogical analyses of a 7.5-meter core from the middle of Lake Valencia, Venezuela, have provided information on the paleoclimatic history of this low-elevation, low-latitude site for the last 13,000 years. The data show that dry climates existed in this region from 13,000 years before present (B.P.) until about 10,000 years B.P. The Lake Valencia Basin was occupied by intermittent saline marshes at that time. About 10,000 years B.P., a permanent lake of fluctuating salinity formed and arboreal plant communities replaced the earlier dominant xeric herbaceous vegetation and marsh plants. By 8500 years B.P., Lake Valencia reached moderate to low salinities and discharged water; the modern vegetation became established at that time. After 8500 years B.P., the lake twice ceased discharging as a result of reduced watershed moisture. The second of these drying episodes is still in progress and has been aggravated by human activities in the watershed.     

辅酶Q10污泥施用对作物和土壤效应的研究

为了探索辅酶Q10污泥施用对土壤和作物的影响,以玉米为供试作物,进行了不同用量污泥施用及与单施化肥对比的田间试验。结果表明,污泥施用增加了玉米的株高,400kg/667m2施肥量比空白区平均增加14cm,比单施化肥区平均增加6.5cm;400kg/667m2施肥量比空白区增产10%~15%,达到差异显著水平,与单施化肥区无显著差异;施用污泥与空白区相比,玉米籽粒蛋白质、脂肪和淀粉含量均有所提高,与单施化肥相比,污泥对提高籽粒蛋白质含量的作用更明显;污泥施用后对提高土壤中磷的作用最大,其次为氮,对有机质和钾的影响微乎其微,对土壤的p H值没有影响。辅酶Q10污泥施用对玉米生长、产量形成和品质均具有良好的效应,同时能够起到培肥土壤的作用。     

阿拉善荒漠草地8种牧草营养物质季节动态及营养均衡价评价

探讨了阿拉善荒漠草地珍珠柴(Salsola passerina)、霸王(Zygophyllum xanthoxylon)、红砂(Reaumuria soon-gorica)、绵刺(Potaninia mongolica)、梭梭(Haloxylon ammodendron)、盐爪爪(Kalidium foliatum)、沙鞭(Psammochloavillosa)和牛心朴子(Cynanchum komarovii)8种牧草营养物质含量的季节动态,并以粗蛋白质对其营养均衡价进行了比较。结果表明:8种牧草的粗蛋白质、粗脂肪、无氮浸出物、钙含量和钙磷比随着牧草的生长期呈先增加后降低的趋势,粗蛋白质含量6月最高,为7.86%~19.18%,1月最低,为5.25%~9.24%;粗脂肪、无氮浸出物、钙含量及钙磷比分别为0.81%~9.63%,26.19%~52.58%,0.12%~1.93%和0.86%~16.00%。粗纤维含量随植物生长呈降低趋势,且8种牧草的含量差异性较大,范围为9.56%~43.01%;粗灰分含量随生长期没有明显的季节动态规律;磷含量随牧草的生长而降低,范围0.04%~0.20%。牧草营养均衡价的评价表明:8种牧草营养均衡价(NB)依次为:梭梭绵刺珍珠柴霸王红砂盐爪爪牛心朴子沙鞭。     

基于改进生态足迹模型的西北地区生态可持续性评价

西北地区的生态可持续状况对于稳定生态环境,改善人地关系具有重要的现实意义。传统生态足迹模型(EFM)中存在诸多不足和缺陷,文中对原有模型进行了改进并对西北地区2012年生态可持续性进行了计算和评价。结果表明:1)西北地区人均生态足迹为2.90hm2/人,人均生态承载力为2.18hm2/人,人均生态赤字为0.72hm2/人,整体的生态结构不合理,处于不可持续状态;2)西北地区各省区的生态足迹差异明显,除青海和新疆为生态盈余外,其它省区均为生态赤字,其中陕西最大,甘肃最小;3)西北地区生态适度人口为0.74×108人,实际人口与生态适度人口的比例是1:0.75,人口数量整体处于超载状态;生态利用效率为0.65万元/hm2。改进生态足迹模型能够较好地评价生态可持续现状,研究方法和结果对于区域生态可持续发展研究具有一定的参考价值。     

Decline in leaf growth under salt stress is due to an inhibition of H+‐pumping activity and increase in apoplastic pH of maize leaves

In this study, salt‐induced changes in the growth rate of maize (Zea mays L.) were investigated during the first phase of salt stress. Leaf growth was reduced in the presence of 100 mM NaCl, and effects were more pronounced for the salt‐sensitive cv. Pioneer 3906 in comparison to the hybrid SR03. While hydrolytic activity of plasma membrane remained unaffected, H⁺‐pumping activity was reduced by 47% in Pioneer 3906, but was unchanged in SR03. Changes in apoplastic pH were detected by ratiometric fluorescence microscopy using the fluorescent dye fluorescein isothiocyanate‐dextran (50 mM). Pioneer 3906 responded with an increase of 0.2 pH units in contrast to SR03 for which no apoplastic alkalization was found. With respect to the hypothesis that the apoplastic pH is influenced by salinity, it is suggested that salt resistance is partly achieved due to efficient H⁺‐ATPase proton pumping, which results in cell‐wall acidification and loosening.