实葶葱种子成熟过程中物质含量变化和萌发能力研究

以实葶葱种子为试材,研究了实葶葱种子成熟过程中物质含量变化和萌发能力。结果表明:种子含水量均随发育天数的增加呈下降趋势,下降到8.28%。而种子的千粒重先增加后降低,种子成熟期的千粒重最高,达0.4406 g。可溶性糖含量逐渐降低至4.44%,而淀粉含量逐渐增加至55.18%,粗脂肪含量增加至32.62%,游离氨基酸含量逐渐下降到0.78 mg/g,蛋白质含量增加到13.43 mg/g,开花后的第68天种子成熟,是种子的适宜采收期。     

新疆托木尔峰国家级自然保护区岩面生地衣多样性的研究

根据实地调查并结合已有的文献资料,对新疆托木尔峰国家级自然保护区岩面生地衣区系进行了研究.结果表明:该地区岩面生地衣共有58种,隶属于6目、18科、35属,其中微孢衣属和平茶渍属种类较多,分别占该地区地衣总数的10.34和15.52％.地衣科目中茶渍目占优势,其科、属、种数分别占该地区地衣总数的72.22,74.28,74.14％.根据地衣对环境的适应特征和选择性,将新疆托木尔峰国家级自然保护区岩面生地衣的地理成分可划分为环北极成分、世界广布成分、中国特有种、欧亚-北美成分、中亚成分、中亚-西亚成分、广泛分布成分等7个分布类型.     

阿勒泰大青河林场地衣物种多样性的研究

根据实地调查资料并结合前人的研究数据,初步鉴定出阿勒泰大青河林场地衣种类52种,隶属于4目、10科、21属.其中茶渍目地衣有6科、16属、42种,分别占该地区地衣科属种总数的60.00％、76.19％、80.77％.优势科主要集中在茶渍目的梅衣科、蜈蚣衣科和石蕊科,占地衣总数的67.31％.根据研究地区的生态环境特征及地衣种类组成,将该地区地衣的地理分布区类型划分为世界广布种、环北极-高山种、北半球大陆广布种、环北方种、环低北极及北方种、东亚种、温带种、两半球广布种、地中海、西亚和中亚种、两极和大西洋种、中国特有种共11种.同时对地衣的生长基物类型进行了统计分析.     

不同增温措施及休眠时间对葡萄生长发育的影响

[目的]通过缩短葡萄休眠期,促使葡萄提早成熟,为吐鲁番设施葡萄促进早熟栽培提供科学依据.[方法]以火焰无核葡萄为试材,设置休眠时间为14、20、27和33 d四个处理,以不作任何处理为对照(CK),通过适宜的温度调控,定期观察比较不同休眠时间对葡萄生长发育的影响.[结果]采用增温措施,可以满足葡萄正常生长的环境条件.不同休眠时间对葡萄的萌芽有影响,休眠14 d比CK提前39 d萌芽,成熟期较CK提前3d,可溶性固形物与CK呈极显著差异,产量无显著差异.[结论]通过不同增温措施,适当控制休眠时间让葡萄提早萌芽,并且在不影响产量的前提下提前结果并成熟,为吐鲁番设施葡萄促早栽培提供了科学参考依据.     

Clear felling and burning effects on soil nitrogen transforming bacteria and actinomycetes population in Chittagong University campus, Bangladesh

The effect of forests clear felling and associated burning on the population of soil nitrogen transforming bacteria and actinomycetes are reported at three pair sites of Chittagong University campus, Bangladesh in monsoon tropical climate. Clear felled area or burnt site and 15-21 year mixed plantation of native and exotic species, situated side by side on low hill having Typic Dystrochrepts soil was represented at each pair site. At all the three pair sites, clear felled area or burnt site showed very significantly (p≤0.001) lower population of actinomycetes, Rhizobium, Nitrosomonas, Nitrobacter and ammonifying as well as denitrifying bacteria compared to their adjacent mixed plantation. From environmental consideration, this finding has implication in managing natural ecosystem.     

Integrated Weed Management Through Tillage and Herbicides for Wheat Production in Rice-Wheat Cropping System in Northwestern Pakistan

Conservational tillage (CT) in combination with broad spectrum herbicide may be more efficient and economical in controlling weeds,reducing cost of cultivation,and enhancing wheat yield.Field experimen...     

新疆大学农场资源土壤动物调查初报

对新疆大学农场资源土壤动物现状进行了首次调查研究,共获标本2050只,隶属于6门,17纲,26目和56种。根据其经济用途分为食用土壤动物、药用土壤动物、饲料土壤动物、天敌土壤动物、环境指示土壤动物和观赏土壤动物6大类,并论述了资源土壤动物的开发利用和保护措施。     

Use of urea coated with natural products to inhibit urea hydrolysis and nitrification in soil

Laboratory incubation experiments were conducted with uncoated urea or urea coated with dementholized oil (DMO), pitch (the mint oil discard), terpenes (the products of menthol mint oil), or dicyandiamide (DCD) to study the retardation of urea hydrolysis and nitrification in soil. Two levels (0.5 and 1 %) of coating were tested. Urea was applied at a rate of 200 mg kg⁻¹ of dry weight of soil. The urea hydrolysis and nitrification processes were inhibited by all three natural products. All the three natural products viz., DMO, terpenes, and pitch significantly retarded urease activity of soil.     

Associations of <Emphasis Type="Italic">NAM</Emphasis>-<Emphasis Type="Italic">A1</Emphasis> alleles with the onset of senescence and nitrogen use efficiency under Western Australian conditions

Wheat grain yield and protein content are significantly influenced by the onset of senescence and the duration of the grain filling phase. The onset of senescence also affects Nitrogen use efficiency (NUE) through interacting pathways involving N accumulation and translocation of N into the grains. The objective of this study was to relate variation in NUE and its components with two groups of the NAM-A1 gene alleles; (i) early onset of senescence in cultivars carrying the NAM-A1a allele, (ii) delayed onset of senescence in cultivars carrying the Non-NAM-A1a allele (b, c, d) in wheat cultivars grown under Western Australia conditions. A field trial was carried out over two seasons examining 19 cultivars under different N rates and time of N application. The Normalized Difference Vegetation Index was utilized to determine the onset of senescence after anthesis. The early onset of senescence results in high grain yield, harvest index, and NUE due to improvements in the N utilization ability. Accelerating the onset of senescence results in a short grain filling period leading to grain maturity before the onset of unfavourable summer conditions. The function of alleles of NAM-A1 gene in controlling senescence hence the NUE is highly regulated by environmental conditions. This study concluded that the function of NAM-A1a allele induces the onset of senescence with a positive effect on the NUE and its components under Western Australian conditions.