氮素形态、用量及施用时期对小青菜产量和硝酸盐含量的影响

采用田间试验研究了氮素形态、用量及施用时期对小青菜产量和硝酸盐含量的影响。结果表明,等氮量施肥下,产量最高的是硝酸钙,尿素+微量元素处理;尿素,有机无机复混肥和碳酸氢铵处理间无显著差异,DMPP处理产量最低;追施微量元素能提高小青菜的产量。硝酸盐含量随着收获时期的延后而降低,有机无机复混肥处理则略有升高,但未达到显著水平;收获期取样时,不同氮肥对硝酸盐的积累是:硝酸钙＞DMPP＞尿素＞有机无机复混肥＞尿素+微量元素＞碳酸氢铵。配施微量元素及氮磷钾的协同吸收均能降低硝酸盐含量。综合考虑产量和品质指标,以有机无机复混肥处理效果较好。小青菜产量和Vc含量随着施氮量的提高而提高,但硝酸盐含量也随之提高;小青菜产量和Vc含量随着施氮时期的延后而降低,硝酸盐含量高峰出现在追肥后20d左右。     

A social learning video method: Identifying and sharing successful transformation knowledge for sustainable soil management in Switzerland

To enhance sustainable land use, a From Farmer to Farmer project was conducted in Switzerland (2001–2010). A multi‐stakeholder discussion group co‐produced nine videos with experienced farmers and wine producers showing sustainable soil management practices. We analysed the video audio‐visual content and drew on reflections of the co‐production process, referring to concepts of system, target and transformation knowledge, as well as on social learning. The analysis showed a broad range of means (or actions) for sustainable soil management in arable land management, fodder production and wine growing that are aligned to transformation knowledge. The research showed that farmers refer to three phases of social learning, light‐bulb moments, coping with challenges and gaining successful expertise. These are not just linear processes of individuals. Four types of social learning were found in the video analysis: (a) learning from observing actions of others, (b) sharing experiences with storytelling, (c) informal social interactions and (d) being a role model with a large social network. Videos enable transformation knowledge to be shared with peers using storytelling; this powerful narrative communication style provides credibility and respects the ‘thought style’ of the target audience group. We conclude that for successful implementation of sustainable actions, it is important to address a specific target group and share their transformation knowledge built upon system and target knowledge. The social learning video method is a viable way to enable social learning between science, administration and practice and has potential for fostering change in sustainable soil management.     

Isolation of new pregnancy-associated glycoproteins from water buffalo (Bubalus bubalis) placenta by Vicia villosa affinity chromatography

The present study describes the isolation and characterization of new pregnancy-associated glycoprotein molecules (PAG) from midpregnancy and late-pregnancy placentas in the water buffalo (Bubalus bubalis). After extraction, the homogenates are subjected to acid and ammonium sulfate precipitations followed by DEAE chromatography. Subsequently, the water buffalo PAG (wbPAG) from these solutions are enriched by Vicia villosa agarose (VVA) affinity chromatography. As determined by western blotting with anti-PAG sera, the apparent molecular masses of the immunoreactive bands from the VVA peaks range from 59.5 to 75.8 kDa and from 57.8 to 73.3 kDa in the midpregnancy and late-pregnancy placentas, respectively. Amino-terminal microsequencing of the immunoreactive proteins has allowed the identification of three distinct wbPAG sequences, which have been deposited in the SwissProt database: RGSXLTIHPLRNIRDFFYVG (acc. no. P85048), RGSXLTILPLRNIID (acc. no. P85049), and RGSXLTHLPLRNI (acc. no. P85050). Their comparison to previously identified proteins has shown that two of them are new because they have not been described before. Our results confirm the suitability of VVA chromatography for the enrichment of the multiple PAG molecules expressed in buffalo placenta.     

野生欧李生长期组织器官中不同形态钙含量的变化及其相关性

 研究了野生欧李萌动期、开花期和果实发育期各组织器官中不同形态钙含量的变化及其相关性。结果表明,野生欧李对钙的吸收积累与钙的形态密切相关,木质部和花器官、果实、果柄中的钙主要以果胶钙形态为主,韧皮部和新梢中的钙主要以草酸钙形态为主。在年生长发育时期,木质部中各种形态钙含量总体呈下降趋势,进入果实成熟膨大期含量回升;韧皮部中各种形态钙含量总体呈下降趋势,进入果实成熟膨大期水溶钙、果胶钙、磷酸钙和草酸钙含量略有回升;花器官和果实中各种形态钙含量变化呈“下降—增加（或下降）—下降”的变化;在果实发育期,新梢中的水溶钙、果胶钙、草酸钙和剩余钙含量明显增加,而果柄中的水溶钙含量增加最为明显。随生长发育进程各组织器官中存在钙形态转化。木质部、韧皮部、花和果实中水溶钙和果胶钙含量的年变化与相应器官中钙总量之间存在高度正相关。     

樱桃番茄在滴灌栽培时氮肥的合理施用量研究

试验结果表明,樱桃番茄在滴灌栽培时,比常规畦灌栽培条件下生长发育得更好,能提高肥料利用率。在产量相同时,滴灌栽培能节省N肥18.75%;产量随着N肥的增加而增加,达到一定用量后由于植株营养生长过剩,产量反而下降。滴灌栽培合理施用N肥时,可以提高果实的品质。     

土壤中汞的化学形态及其影响因素

An investigation and on 13-year-old(1984-1996) Chinese fir and Tsoong‘s tree mixed forests in Jianou City,Fujian Province,China was carried out to compare the influences of different interplanting types of individual tree-tree,row-row,row-strip(three rows)and pure Chinese fir stands on soil properties.Compared with the pure stands of Chinese fir ,the mixed stands exerted a posivtive effect on soil fertility,with increases in soil organic matter,total N,available P and available K.Moreover,improvements were also observed in soil enzymatic activities ,aggregate structure,structure,stability,status of soil porosity,soil aeration and penetrability in miexd stands.The row-row interplanted stands had the best effect on tree growth and soil properties among these mixed forests.In the southern subtropical region,the spreading of the row-row mixing model of the two tree species would be helpful to preventin ghe soil from fertility deterioratio caused by successive plantation of Chineses fir.     

塔落岩黄芪、细枝岩黄芪及其变异型的生理特性研究

本文研究了毛乌素沙漠地区塔落岩黄芪和细枝岩黄芪及其变异型的生理学特性。结果表明,塔落岩黄芪和细枝岩黄芪各与其变异型之间在生理特性方面存在着极其显著的差异。     

维生素C对虾类生长和健康调节作用研究进展

在集约化养殖条件下,确保虾类健康是养虾业可持续发展的关键.维生素C作为鱼虾类重要的营养和免疫调节物在水产业已得到广泛应用.国内外针对维生素C对虾类的影响已开展了诸多研究,主要集中在估计最大生长和免疫反应所需的最低维生素C需求,以及制定成本最低的饲料.但是,维生素C对虾类的健康调节作用和机制还需进一步研究.本文综述了维生...     

不同氮素形态及配比对蔬菜生长和品质的影响

分别以纯水和自来水为生长介质对莴笋和菠菜进行水培试验,以揭示不同氮素形态及配比对蔬菜生长和品质的影响。结果表明,以纯水为水培水源,ＮＯ－３－Ｎ∶ＮＨ＋４－Ｎ为１∶１或单独供应ＮＨ＋４－Ｎ,对作物生长均有一定程度的抑制作用,而以后者的生长量最低。以自来水作水培介质时,以ＮＯ－３－Ｎ为唯一氮源预培养一段时间后,再提高营养液中ＮＨ＋４－Ｎ比例,有利于蔬菜的生长发育及硝酸盐含量的降低,使莴笋维生素Ｃ含量也有所降低,菠菜则无明显变化。当植物生长量较大时,尿素作水培氮源不能满足作物对氮素的需求     

儿童用凝胶贴膏的研究进展

本文从凝胶贴膏在儿童用药的应用情况、作用机制、基质组成与配比以及儿童用凝胶贴膏的特点等方面,综述了近年凝胶贴膏在儿童用药的研究与应用情况,并对开发应用前景提出展望,以期为进一步的研究提供参考。