新农村建设筹资中的问题与对策

新农村建设是一项复杂的系统性工程,有无充足的资金支持决定了新农村建设的成败,该文分析了现有的主要筹资渠道的问题,提出了如何完善现有筹资渠道,广开源头,为新农村建设提供不竭的动力支持的建议。     

金针菇航天种菌丝诱变效应的研究

本实验以2个金针菇航天诱变菌种(航金1号和航金2号)和地面对照菌种(江山白)为材料,进行了拮抗实验、菌丝生长速度实验、抗杂性实验和酯酶同工酶分析实验研究,结果表明,金针菇航天种与对照之间有拮抗现象,但无拮抗线。航天搭载菌株的菌丝生长速率比对照快,其中航金1号生长速度最快。航金1号和航金2号均表现出较强的抗杂性,能抑制并盖过霉菌菌丝生长。通过酯酶同工酶聚丙烯酰胺凝胶电泳分析发现,航金1号和航金2号与对照相比都出现了特异谱带,说明经过航天诱变的菌株发生了一定的突变。     

Shoot nitrate reductase activities of field‐layer species in different forest types. II

Analysis of in vivo shoot nitrate reductase activity (NRA) of the grass Deschampsia flexuosa (L.) Trin. has been proposed as a method of indicating the availability of nitrate in northern temperate forest soils. We report the seasonal variation in NRA and the influence of temperature on the NRA assay. Studies were performed in the field or on natural populations on topsoil monoliths in a greenhouse.

The induced in vivo NRA as measured at 28°C was higher in plants grown at lower than at higher temperatures within the range 4–20°C, although the induction was faster at higher temperatures. When the assay was performed at various temperatures, enzyme activity was much lower at lower temperatures. The accumulation of organic nitrogen in shoots showed that reduction actually increased with temperature. Transfer of monoliths from high to low temperature led to an increase of in vivo NRA within a day, whereas the decline caused by the reverse began after six days. Variations in temperature accounted for between 0 and 80% of the seasonal variation in NRA in the field, depending on the influence of the variability in nitrate supply.

Maximally induced NRA after application of nitrate was mostly higher in a clearfelling than in a closed forest. In the forest, there was a close correlation between current and maximally induced NRA. One interpretation of this result is that low availability of nitrogen may have been a cause of the lower maximally induced NRA there. This is supported by results from other studies.

We conclude that variations in temperature and availability of nitrogen, particularly nitrate, are largely responsible for seasonal variations in NRA. The influence of temperature can be adjusted for.     

Establishment of Efficient Regeneration System of Populus×euramericana cl.‘Bofeng’

Compared with the species of Leuce section,the difficulty in plant regeneration during tissue culture for the species of Aigeiros section is a key limiting factor for their application in genetic engineering of forest trees.In this study,the plant growth regulators combination,copper concentration,light intensity,and the selection pressures of kanamycin were investigated using leaves of Populus×euramericana cl.’Bofeng’ as explants,and a stable and high efficient regeneration system was established.Using this system,both the shoot regeneration rate and rooting rate were up to 100%,and the average number of differentiated shoots in each leaf explant was up to 20,and the survival rate of seedlings reached 98%.The optimal selection pressure of kanamycin in shoot inducement for leaf-explant was 40 mg·L^-1,and the optimal selection pressure of kanamycin in root inducement of adventitious bud was 20 mg·L^-1.The authors also found that differentiation rate of adventitious buds of P.×euramericana cl.’Bofeng’ could be significantly promoted by increased copper concentration,and this is the first report about the key role of copper（Cu） in explant regeneration of Poplars.This regeneration system with high frequency which was established by the authors was as good as that of species of Leuce section,and it provides a good technological platform for genetic engineering of forest tree which uses the species of Aigeiros section as model materials.     

多穗型青贮玉米科多8号制种技术比较

科多8号是中国科学院遗传研究所选育的青饲青贮玉米专用品种,深受北方农牧市场的欢迎。但由于制种生产比较效益较低等原因,群众没有制种积极性。文章结合多年来制种工作的经验和近年进行的一些试验研究,从播种期、父母本安排、去雄方法等方面进行深入研究探讨,并提出高效制种模式。     

兴安盟扎赉特旗杨树病虫害的种类及其防治措施

对本地区杨树烂皮病的抗性树种进行了调查,筛选出最适合本地区栽植的抗病品种——小乘黑（P.Canadensis）和银中杨（P.alba‘Berolinensis’）。对天牛成虫进行了不同药剂不同浓度的防治对比试验,筛选出最合适的药剂——绿色葳蕾250倍液和触破800倍液。对其他地区的杨树病虫害的预防和控制能起到一定的借鉴作用。     

通河县林地保护规划落界数据说明

林地图斑落界是林地保护利用规划编制工作的主要环节,是落实林地图斑空间位置、核实资源基数,查清森林资源现状的基础性工作。笔者详细论述了通河县林地保护规划落界数据的基本情况、图斑落界方法和结果比较,对林地保护利用规划编制工作具有参考价值。     

大兴安岭湖通河野生五味子药用资源保护区自然生态质量评价分析

从植被类型多样性、物种多样性、生态系统的稳定性和脆弱性、面积适宜性几个方面对大兴安岭湖通河五味子药用资源保护区的自然生态质量进行了评价和分析。     

Effect of Water and Rice Straw Management Practices on Soil Organic Carbon Stocks in a Double-Cropped Paddy Field

ABSTRACT

Water and rice straw (RS) management practices can potentially affect the accumulation of soil organic carbon (SOC) in agricultural soils. Field experiments were conducted in two consecutive rice-growing seasons (wet and dry) to evaluate SOC stocks under different water (continuous flooding [CF], alternate wetting and drying [AWD]) and RS management practices (RS incorporation [RS-I], RS burning [RS-B], without RS incorporation and burning [WRS]) in a double-cropped paddy field. RS-I under AWD had higher volumetric water content than the same RS management under CF at tillering in both growing seasons. Total SOC was significantly higher under AWD at tillering in both wet and dry seasons and after harvesting in the dry season compared with CF. The same trend was also observed for C:N ratio at tillering and after harvesting in the dry season. RS-B plots had lower SOC stocks than RS-I and WRS plots across most of the measuring periods regardless of the growing seasons. SOC stocks were 33.09 and 39.31 Mg/ha at RS-B and RS-I plots, respectively, in the wet season, whereas the respective values were 21.45 and 24.55 Mg/ha in the dry season. Incorporation of RS enhanced SOC stocks under AWD irrigation, especially in the dry season before planting. Soil incorporation of RS in combination with AWD could be a viable option to increase SOC stocks in the double-cropped rice production region as it is strongly linked with soil fertility and productivity. However, the environmental consequences of RS incorporation in irrigated lowland rice production system should be taken into consideration before its recommendation for paddy field on a large scale.     

杂草稻对粳稻生长及产量的影响

在同期播种情况下,和粳稻相比,杂草稻出苗时的叶片更肥长、营养生长期的植株更高、分蘖数多达4倍以上。不同生物型杂草稻的落粒性差异较大。杂草稻密度愈高对栽培粳稻的产量影响愈大。