影响土壤氮素径流流失的因素探析

从自然因素和人为因素出发探讨了地形、降雨、土壤理化性质、植被以及施肥、耕作制度等因素对土壤N素流失的影响,并综述了国内外有关研究的最新进展。并认为,基于这些因素相互作用的复杂性,有必要开展以下3方面的内容:一是大量开展多因子交叉实验,定量评价它们之间的关系,这为深入理解土壤N素流失机理和确定流域非点源污染模拟模型参数提供科学依据;二是加强有关土壤N素流失机理的多学科之间的联系,协同攻关建立较完善的理论认识;三是利用微观径流小区开展田间试验,结合遥感和GIS分析等方法,建立宏观大尺度土壤N素流失模型,为环境问题的宏观决策提供支持。     

华北地区水安全问题的研究与展望

This paper addresses the emergence of water security problems in North China with the aim of highlighting key water resources management and water security issues for the long-term development of North China. Three key problems related to water resources and security issues in North China in the 21st century are addressed, namely 1) the water cycle under environmental change, 2) agricultural water saving, and 3) water security. Development of international research related to these issues is also reviewed. The research plan developed recently by the Chinese Academy of Sciences (CAS) is discussed and suggestions on research and development of water resources science in North China are presented. Thanks to focus on experimental catchments and dedicated research stations, a detailed knowledge of the water cycle on North China farmland has been compiled. A range of techniques that include isotope tracers has been used to acquire hydrologic data. Much research has been devoted to developing distributed hydrological models at different scales. In the well irrigation district, five different water saving irrigation regimes have been investigated, and these regimes have had widespread application, and reduced water use 60-150 mm while they increased water use efficiency (WUE) by 20%-30%. Furthermore, preventing water pollution is the most essential step to ensure North China's water security.     

木本植物原生质体培养体系研究进展

为了给木本植物原生质体培养技术体系的建立提供理论依据,推动木本植物快速繁殖和品种遗传改良工作的开展,从原生质体分离、纯化、培养方式等方面对木本植物原生质体培养体系进行了详细阐述,对比分析了原生质体不同分离方法和培养方式的优缺点,研究总结出影响原生质体培养的主要因素,并提出了木本植物原生质体培养今后的研究重点。     

磷胁迫对不同油茶优良无性系Apase活性的影响

为揭示磷素胁迫条件下油茶无性系Apase的变化规律和筛选磷高效利用型油茶无性系,本文通过沙培试验设计3种磷素处理水平（0、0.05、0.5 mmol/L）,进行磷胁迫条件下不同油茶无性系Apase活性的比较研究。结果表明：低磷处理（P0、P1）根系分泌、根系和叶片APase活性均明显高于正常供磷处理（P2）;不同油茶无性系对磷缺乏的适应性存在明显差异,在低磷胁迫下,‘湘林81’、‘湘林4’根系分泌性Apase活性较强,表明其能较好利用土壤中的难溶性磷来适应低磷环境;‘湘林67’具有较高的根系和叶片Apase活性,表明其能有效地重复利用自身体内的有机磷来适应低磷环境。相关性分析表明根系APase活性与净光合速率存在较大的正相关性,叶片APase活性与净光合速率存在一定的正相关性。     

Water Security Problem in North China： Research and Perspective

This paper addresses the emergence of water security problems in North China with the aim of highlighting key water resources management and water security issues for the long-term development of North China. Three key problems related to water resources and security issues in North China in the 21st century are addressed, namely 1） the water cycle under environmental change, 2） agricultural water saving, and 3） water security. Development of international research related to these issues is also reviewed. The research plan developed recently by the Chinese Academy of Sciences （CAS） is discussed and suggestions on research and development of water resources science in North China are presented. Thanks to focus on experimental catchments and dedicated research stations, a detailed knowledge of the water cycle on North China farmland has been compiled. A range of techniques that include isotope tracers has been used to acquire hydrologic data. Much research has been devoted to developing distributed hydrological models at different scales. In the well irrigation district, five different water saving irrigation regimes have been investigated, and these regimes have had widespread application, and reduced water use 60-150 mm while they increased water use efficiency （WUE） by 20%-30%. Furthermore, preventing water pollution is the most essential step to ensure North China＇s water security.     

Evaluation of alternative rice planthopper control by the combined action of oil-formulated Metarhizium anisopliae and low-rate buprofezin

BACKGROUND: High resistance of brown planthopper (BPH) Nilaparvata lugens Stål to common insecticides is a challenge for control of the pest. An alternative control strategy based on the combined application of fungal and chemical agents has been evaluated. RESULTS: Three gradient spore concentrations of oil‐formulated Metarhizium anisopliae (Metschnikoff) Sorokin (Ma456) were sprayed onto third‐instar nymphs in five bioassays comprising the low buprofezin rates of 0, 10, 20, 30 and 40 µg mL^?1 respectively. Fungal LC₅₀ after 1 week at 25 °C and 14:10 h light:dark photoperiod decreased from 386 conidia mm^?2 in the buprofezin‐free bioassay to 40 at the highest chemical rate. Buprofezin (LC₅₀: 1647, 486 and 233 µg mL^?1 on days 2 to 4) had no significant effect on the fungal outgrowths of mycosis‐killed cadavers at the low application rates. The fungal infection was found to cause 81% reduction in reproductive potential of BPH adults. In two 40 day field trials, significant planthopper (mainly BPH) control (54–60%) was achieved by biweekly sprays of two fungal candidates (Ma456 and Ma576) at 1.5 × 10¹³ conidia ha^?1 and elevated to 80–83% by incorporating 30.8 g buprofezin ha^?1 into the fungal sprays. CONCLUSION: The combined application of the fungal and chemical agents is a promising alternative strategy for BPH control. Copyright © 2010 Society of Chemical Industry     

家蚕品种“菁松×皓月”的蚕茧荧光显色判性改育试验

菁松×皓月是生产上推广量最大的春用多丝量家蚕品种,根据家蚕茧荧光色的遗传机制,将该品种改育成具有蚕茧荧光显色判性性状的品种。对蚕茧有多种荧光显色的菁松通过系统分离方法,对蚕茧单一荧光显色的皓月通过杂交导入荧光伴性基因Fx及定向培育的方法,将2个品种均改育成雄蚕茧为黄荧光色、雌蚕茧为紫荧光色的品种,其荧光判性准确率达到100%。2个改育的品种暂命名为苏杰、豪胜。实验室饲养鉴定成绩表明改育品种杂交组合苏杰×豪胜的幼虫比菁松×皓月发育快,体质更强健,但全茧量略低;缫丝鉴定苏杰×豪胜的茧丝纤度2.686 dtex,洁净95.5分,茧丝长1 300 m以上,解舒率75%以上,并且生丝匀度好。改育品种杂交组合苏杰×豪胜的主要经济性状成绩与菁松×皓月相仿,在生产上推广应用可以达到雌雄蚕茧分别缫丝和提高蚕种制造鉴蛹工效的目的。     

吉林省82年来育成大豆品种的产量和叶片部分生理特性变化及其相互关系

对吉林省1923—2005年间育成的42个大豆品种叶片部分生理特性及其与产量关系的研究表明, 大豆产量随育成年代的推进呈线性增加, 82年增加了95.94%, 平均每年增加1.17%; 与此同时, 叶片硝酸还原酶活性、可溶性糖含量、比叶重、叶绿素含量、可溶性蛋白含量均随年代推进而增加, 且与产量呈正相关; 在V₄期(第4节期, 主茎第3个复叶全展), R₂期(盛花期), R₄期(结荚盛期), R₆期(鼓粒盛期)等不同生育时期的生理指标变化不同, 把它们作为选择高产品种的参考指标具有一定的应用价值; 硝酸还原酶活性在V₄期、R₂期、R₆期与产量呈极显著正相关, 在所有指标中表现最稳定, 作为高产品种的选育指标最具可行性。     

油茶冻害及其防治措施

油茶是中国南方最重要的木本食用油料树种之一,其主要产品茶油是高级保健食用油。油茶耐低温能力强,短时可耐低温-10℃,但持续低温对油茶生长和产量会造成影响。尽管在中国南方油茶主产区极少发生持续低温现象,但2008年冰冻使经济林遭受了巨大的损失。针对此现象,文章分析了油茶冻害发生的原因,总结了油茶不同部位发生冻害的主要症状,提出了预防油茶冻害的物理和化学方法,最后提出了油茶冻害后的补救措施。     

半干旱区玉米不同光照强度的光合特征分析

以郑单958、先玉335为试验材料,在五个密度水平下对不同光强的光合要素进行了分析。结果表明,在1300~1900μmol·m-2·s-1光强范围内,净光合速率随光强的升高逐渐增加,各密度处理在1700μmol·m-2·s-1和1900μmol·m-2·s-1光强下,净光合速率达到最高。相同光照强度下,30 000株·hm-2密度的净光合速率最大,90 000株·hm-2密度的净光合速率最小。适宜密植,虽然降低了单株的光合能力,但群体光能利用率得到显著提高,利于群体干物质积累及产量的提升。