水稻耐寒变异体筛选

从４个水稻品种的３６０个愈伤组织株系中筛选出４个耐寒变异株系。叶绿素荧光测定法（ＣＦＡ）的结果表明，这４个耐寒变异株系的再生植株在４℃条件下的光合效率明显高于原品种。由于各原品种的遗传基因型不一样，接种种胚的愈伤组织的诱导率、愈伤组织在低温筛选下的存活率、耐寒愈伤组织株系的分化率均有不同。使用稍加修改的ＢＭ诱导和增殖培养基、分化培养基及生根培养基，用低温、常温交替培养筛选法的愈伤组织株系的存活率、分化率高于持续低温培养筛选法的。     

沙棘根系的生物学特性与造林地选择

沙棘有很强的根蘖能力,其根系具有类似水生植物根系的解剖特征,地上部分又有旱生植物的特征,所以沙棘应属中生植物;沙棘根系有很强的生物学可塑性,对林地的水分状况会产生明显反应;在植株个体发育早期,多在生长较慢的侧根上形成具有多种功能的根瘤。沙棘造林,应充分考虑其根系生物学特性和解剖特征,根据经营目的选择相应的造林地或采取整地措施改地适树,满足其水分要求。     

Comparison of Coleoptera assemblages from a recently burned and unburned black spruce forests of northeastern North America

Several insect groups have adapted to fire cycles in boreal forests, and can efficiently use new habitats created by fire. Our study aimed at producing a first characterization of post-fire Coleoptera assemblages of black spruce forests of eastern North America. For two years, we sampled Coleoptera using flight-interception traps in burned stands of contrasting age and structure in a 5097-ha wildfire and in neighbouring unburned mature stands. More than 40 species were exclusively captured in burned stands. Time elapsed since fire and proximity of unburned forests were the most significant parameters affecting Coleoptera assemblages. Stand age and structure had limited effects on assemblage structure; the Scolytid Polygraphus rufipennis Kirby was the only common species to clearly favor older stands. Fire-associated Coleoptera assemblages found in our study area were clearly distinct from those found in similar unburned stands; we should thus be conservative in our management approach concerning recently burned stands.     

Adaptive selection of foraging and nesting habitat by black kites (Milvus migrans) and its implications for conservation: a multi-scale approach

Black kites (Milvus migrans) are vulnerable and in decline within Europe. Here, we investigate selection of foraging and breeding habitat in a high-priority population in the Italian pre-Alps. Compared to a random distribution, kites foraged preferentially near water, over extensively managed grassland and within 1 km of nest-sites. Urban areas were positively selected near lakes but otherwise avoided. Foraging performance was higher over water than over terrestrial habitats. Kites nested on cliffs and trees and preferentially near water, far from paths and villages and in rugged and steep micro-sites. Tree-nests were located in the most mature tree in the stand. Productivity was positively related to the availability of water bodies. Therefore, food availability and human disturbance/persecution limited foraging and breeding performance. Guidelines to maintain or enhance current population levels include: (1) setting up reserves covering 10% of the areas within 1 km of large lakes; (2) converting current derelict coppice-woodland to high forest; and (3) enhancing subsidies for extensively managed grassland. Our results highlight the importance of cross-scale models integrating selection of foraging and breeding habitat and reinforce the importance of the spatial configuration of key resources for more realistic conservation management in mosaic landscapes.     

夏玉米在“3414”试验方案中氮磷钾配施的肥料效应研究

[目的]为研究氮肥、磷肥、钾肥对夏玉米产量和经济效益的影响和测土配方施肥提供依据。[方法]在河南省鹤壁市利用"3414"试验设计,布置夏玉米氮、磷、钾肥料效应试验。[结果]氮的缺乏对夏玉米产量影响最大,其次为磷,最后为钾。[结论]施肥量推荐类型:夏玉米目标产量10 500 kg/hm2,氮磷钾配比用量18∶8∶6;夏玉米目标产量9 000~10 500 kg/hm2,氮磷钾配比用量为16∶6∶4;夏玉米目标产量9 000 kg/hm2以下,氮磷钾配比用量为14∶4∶2。     

不同生境具抑菌作用的海洋真菌筛选

[目的]为了测定海口沿海海域不同生境的海洋真菌抑菌状况。[方法]从海口西海岸沿线、南渡江入海口以及演丰红树林3个生境分离到162株海洋真菌,通过药敏纸片法测定海洋真菌代谢产物对4株病原细菌的抑菌活性。[结果]82.72%的海洋真菌具有不同程度的抑菌作用,其中分离自红树林生境的海洋具有抑菌作用的程度最高,西海岸生境分离的真菌次之,入海口生境分离的海洋真菌具有抑菌作用的概率相对最低。[结论]从不同生境分离到的海洋真菌,其抑菌效果也不一样。因此,当需要筛选某种活性的海洋真菌时,可到具有较易筛选出该活性的生境中筛选。     

渝东南寺观园林选址与建筑布局特征

渝东南地区独特的地貌为寺观园林选址创造了丰富的条件,且大部分的寺观园林是与山地相结合而修建的山地型寺观园林.笔者将渝东南寺观园林与山体的结合方式分为山顶型、山腰型、山麓型,认为寺观周边环境主要有寺观置于旅游开发古镇之中和置于山林自然景区之中两种.渝东南山林景区中寺观规模大小不一,建筑布局也各有千秋,现存的寺观园林的建筑布局主要有井院式布局、线性布局和综合布局方式.研究渝东南寺观园林的环境特征,旨在为充实地方寺观园林研究,补充巴渝园林特点做出贡献.     

邯郸地区黄连木优良单株的选择

邯郸地区黄连木资源分布集中,变异丰富。为给黄连木的丰产栽培提供优良株系,对其生物学特性、生长特性、果穗性状、单株结实量和抗虫性等主要性状进行实地调查。结果表明,从25株候选优株中,筛选并确定出单一性状优良的黄连木单株10株;通过多性状综合选优分析,选择出单株结实量高、果实出油率高、抗虫力强等综合性状优良的黄连木优株6株。     

贵州省猪源沙门氏菌Ⅰ类整合子与耐药基因盒研究

为了调查规模养殖场沙门氏菌中Ⅰ类整合子的流行情况,采用聚合酶链式反应检测了从贵州省规模养猪场分离的57株沙门氏菌中Ⅰ类整合子的携带率以及整合子中耐药基因盒的种类;采用微量肉汤稀释法测定了57株沙门氏菌对12种抗菌药物的敏感性;并应用χ2检验检测Ⅰ类整合子阳性菌株与阴性菌株耐药性的相关性。结果显示,57株沙门氏菌中Ⅰ类整合子检出率为40.4%(23/57);耐药基因盒检出率为31.6%(18/57);整合子中携带可分别介导对氨基糖苷类和磺胺类药物耐药的aad A2、aad A5、aad A22、aad A23b、dfr A1、dfr A12和dfr A17基因;57株沙门氏菌对12种抗菌药物的耐药率不同,Ⅰ类整合子与多重耐药之间有明显的相关性。