广西来宾县干旱系统分析及生态治旱对策

来宾是广西最旱的县，干旱频繁，严重影响农业生产和农村经济的发展。本文系统分析了该县干旱的原因，认为自然条件和人类活动的影响是干旱致灾的原因。针对农业生态经济系统存在的问题，提出了关于调整系统结构、增强系统功能的生态治旱对策。     

徐州泉山自然保护区人工林下土壤容重与孔隙度时空变化研究

通过对设于泉山自然保护区人工侧柏林与刺槐林的4块测试样地的土壤容重进行测定,同时与裸地进行对比,结果表明,该保护区人工林下土壤容重与孔隙度随时间无确定的变化规律;而在人工林下土壤空间结构变化规律明显：不管在任何时间段,均表现出该土壤容重随土层深度增加而逐渐增大,土壤孔隙度随土层深度增加而逐渐减小的规律,并且侧柏林改变土壤容重的作用大于刺槐林。另外,该土壤容重均小于裸地,人工林通过腐殖质作用能够降低土壤容重,使其土壤通透性及保肥能力较好。     

Results of activities to maintain landraces and other material in some European countries in situ before 1945 and what we may learn from them

All three recommendations to maintain landraces in European countries, given in 1927: 1. maintenance by traditional farmers, 2. maintenance by school personnel and pupils, and 3. maintenance by small agricultural institutions, were disregarded. The present outcome: maintenance by genebanks, which often grow landraces and improved cultivars of one crop next to each other, and which often are part of a large agricultural research institute, was advised against.The above observation may be of value to those who at present advocate maintenance of landraces by traditional farmers in developing countries.It is recommended that landraces should be collected and maintained in genebanks as this will result in a partial loss of the material, whereas on farm maintenance (in situ conservation) would lead to a complete loss.     

氨基酸螯合微肥对旱作水稻苗期生长及生理效应的影响

通过盆栽试验研究氨基酸螯合微肥（AA-Met）对早作水稻苗期生长的影响。结果表明：AA-Met能显著提高早作水稻的株高、根长及生物量。喷施后72h内每24h用SPAD-502测定叶绿素相对含量，发现旱作水稻对螯合态微肥的吸收同化速率显著大于无机微肥，但AA—Met与EDTA—Met（EDTA螫合微肥）间差异不显著。等量施用微量元素下，AA—Met和EDTA—Met处理的生物量、叶绿素和生长素含量均显著高于无机微肥处理，而两螯合态微肥处理间差异不显著。可溶性蛋白含量3种微肥处理间差异显著，表现为AA-Met处理〉ED—TA—Met处理〉无机微肥处理（P〈0．05），表明AA—Met可完全替代EDTA—Met。分别喷施稀释100（AA—Met1）和250（AA—Met2）倍AA—Met的溶液时，作物生物量、叶绿素、生长素及可溶性蛋白含量两处理间差异不显著，但显著高于喷施稀释500（AA—Met）倍的AA—Met溶液的处理。     

滦河流域生态系统健康评价研究

总结了国内外对流域生态系统进行健康评价的实践,以生态系统健康理论和“压力—状态—响应”模型为基础,构建了滦河流域(内蒙古山区部分)的生态系统健康评价指标体系。采用层次分析法进行的综合评价结果表明:滦河流域生态环境健康状态得分为0.82,健康指数为0.48。滦河流域应加强水土保持,减少土壤侵蚀;加大围栏育草、禁牧、休牧、轮牧等力度,治理沙化草场,恢复植被;降低单位面积农药施用量,以减少流域非点源污染;减少对流域内湿地的围垦和破坏;有计划地恢复河滨湿地生态系统,促进河流生态功能恢复。     

中药有效成分对小鼠2-细胞胚胎体外发育的作用

如何获得更多具有活力的可操作的桑椹胚、囊胚一直是胚胎体外培养的研究热点。近二十年来,虽经采用改进培养液成分、改善培养条件、建立体细胞与胚胎共培养体系和添加生长因子、细胞因子等手段,胚胎质量有所提高,但体外受精卵的囊胚发育率仍远低于体内受精,与体内受精囊胚相比,体外受精囊胚的细胞总数和内细胞团细胞数量明显减少,胚胎移植妊娠率和产仔率较低,这些问题均严重影响了胚胎工厂化生产和胚胎产业化的发展,以及育种工作的进程。因此,探索开辟胚胎体外培养生长发育的新途径,提高其发育率和移植妊娠率显得尤为必要。目前,国内外有关中草药有效成分对体外胚胎发育作用的研究甚少。本研究以ICR小鼠2-细胞胚胎为试验材料,将中药有效成分黄芩苷(Baicalin,Bai)、川芎嗪(Ligustrazine,Lig)和小檗碱(Berberine,BR)添加于mCZB基础液中,并以添加双抗的mCZB基础液为试验对照组,比较其对胚胎体外发育的影响。结果表明,体外培养120 h的胚胎孵化率,Bai组(80.6%)、Lig组(78.3%)及BR组(75.9%)极显著高于对照组(51.8%)(P<0.01)。孵化胚胎细胞计数,BR组、Lig组和Bai组(分别为87.2±8.6、83.9±7.7和81.9±6.2),与对照组(77.4±5.6)差异极显著(P<0.01)。说明3种中药有效成分均能显著促进小鼠早期胚胎的体外发育及胚胎细胞增殖。为进一步探讨Bai、Lig、BR对胚胎体外培养发育的效果和验证其胚胎质量,将不同组别培养至桑椹、囊胚期的胚胎进行两种程序常规冷冻,解冻后继续培养,观察其冷冻效果,并将各组解冻后发育至囊胚期胚胎移植。结果表明:冷冻解冻桑椹胚体外培养8~14 h囊胚发育率,程序一中Bai组(65.8%)和Lig组(81.1%)分别显著(P<0.05)和极显著(P<0.01)地高于对照组(48.6%)和BR组(46.7%);程序二中Bai组(80.6%)、Lig组(78.3%)极显著高于对照组(55.2%)和BR组(47.6%)(P<0.01)。冷冻解冻囊胚体外培养6~8 h囊胚发育率,程序一中各组间无显著差异(P>0.05);程序二中,中药有效成分各组间差异不显著(P>0.05),但均显著高于对照组(P<0.05)。两种冷冻程序效果差异不显著(P>0.05)。移植妊娠率和产仔率,Bai组(56.3%,63.3%)、Lig组(52.6%,67.3%)和BR组(55.0%,60.5%)均高于对照组(46.2%,52.8%)。说明3种中药有效成分对于提高小鼠2-细胞胚胎体外发育质量具有一定促进作用,并有利于提高冷冻解冻后移植胚胎的发育潜力。     

In situ evaluation of fruit yield and estimation of repeatability coefficient for major fruit traits of umbu tree [Spondias tuberosa (Anacardiaceae)] in the semi-arid region of Brazil

The umbu tree (Spondias tuberosa) is a xerophytic woody species endemic to the northeast of Brazil. The present work reports a three-year in situ evaluation of major yield components in a random set of trees in Petrolina city, Pernambuco State, Brazil and the application of repeatability coefficient in the context of genetic resources utilization. Five traits were assessed: total fruit yield per plant (FY); total number of fruits per plant (NF); average fruit weight (FW); average pulp weight (PW) and average fruit diameter (FD). The values observed for FY ranged from 4.2–184 kg with mean of 61.5 kg. The values for NF ranged from 257 to 12,981 fruits/tree with mean 3,993 fruits. For FW, the range was from 10.82–23.36 g with mean of 16.03 g. The values for PW ranged from 7 to 17 g with mean of 11.2 g, while FD values varied from 2.5 to 3.5 cm with mean of 3.0 cm. Six methods were employed to estimate repeatability coefficient (r) for all parameters. The r ranged from 0.68–0.76 for NF; 0.87–0.89 for FW; 0.65–0.75 for FY; 0.64–0.78 for PW and 0.70–0.84 for FD. Narrower ranges across methods were observed to r-values greater than 0.80, as observed for FW and FD. Three to four years of measurements will be necessary for FY, NF, and PW and one year for FW to obtain a precision of 90% to provide a reliable identification of individuals for in situ or ex situ conservation.     

夏季休牧对高寒矮嵩草草甸温室气体排放的影响

以高寒矮嵩草草甸为研究对象，利用密闭箱－气相色谱法，对夏季休牧8a的围栏草地(休牧草地)和全年放牧的草地(放牧草地)的温室气体排放通量、土壤特性和生物量进行了对比研究。结果表明：与放牧草地相比，休牧草地植被盖度较之高41％，单位面积生物量较之高53％。同时，土壤特性也有较大不同；休牧草地的植被－土壤系统CO₂排放通量比放牧草地低20.7％，测定期间两者CO₂排放通量以每天每公顷排放C的质量计分别为30.7和38.7 kg·(hm²·d)^-1；试验期间高寒矮嵩草草甸植被－土壤系统是大气CH₄的弱汇，休牧后草地土壤对CH₄的吸收能力增强，休牧和放牧草地CH₄的平均吸收强度分别为28.1和21.9 g·(hm²·d)^-1；休牧草地土壤N₂O排放通量比放牧草地低，两者排放通量分别为4.5和7.6 g·(hm²·d)^-1。可见，夏季休牧措施降低了草地对大气中温室气体浓度增加的贡献。     

贵州习水国家级自然保护区森林土壤理化性状研究

在贵州习水国家级自然保护区内,根据不同的森林植被分布状况及相应海拔高度设置了13个具有代表性的标准调查样地,分别采集土壤测定其理化性状,结果表明:(1)自然保护区森林土壤容重为1.07～2.06g/cm3;土壤总孔隙度为34.9%～83.4%;森林土壤的最大蓄水量为1479.00 t.hm-2～5517.00 t.hm-2;土壤的平均初渗速率和稳渗速率分别为9.05mm.min-1和3.32mm.min-1。(2)自然保护区森林土壤主要为酸性土壤,pH值在3.72～5.97之间变动;土壤有机质的含量为74.83g/kg;土壤全N和有效N分别为2.01g/kg和215.09mg/kg;土壤的全P含量为0.33g/kg;土壤速效磷含量在1.10～84.92mg/kg之间波动,平均含量为8.02mg/kg;土壤的全K和有效K含量分别为11.81g/kg和64.37mg/kg。(3)习水自然保护区所分布的森林植被类型在改良其森林土壤的物理特性,提高土壤的贮水能力,丰富土壤有机质及其N、P、K的含量,增强和维护土壤肥力等方面都具有较显著的生态功能。