石漠化生态恢复过程中土壤磷含量的比较研究(英文)

[Objective] The research aimed to study change law of phosphorus content of soil in karst rocky desertification region(KRD) during eco-restoration process such as Northwest Guangxi Province.[Method] The soil samples were collected from typical KRD in Pingguo County and Yizhou City.The determining quotas of different soil samples such as soil total phosphorus content and available phosphorus content were detected,in addition the soil total phosphorus content,available phosphorus content, urease activity, catalase activity and organic matter content in different soil samples were analyzed comparatively.[Result] Aspect,vegetation type and recovery time generated obviously influences on phosphorus contents in different soil samples.The concrete influence order was listed as follow: phosphorus content in soil of south slope was higher than that in soil of north slope;phosphorus content in soil where Zenia insignis Chun was planted was higher than that in soil of closed forest and that of soil where Dendrocalamus minor Var. amoen was planted,additionally,phosphorus increased with recovery time. Urease activity could be used as a monitoring index of soil fertility because it is related to the change of phosphorus content.[Conclusion] The soil of karst rocky desertification region in Northwest Guangxi Province could be recovered gradually if excessive human disturbance was stopped.If proper natural method of recovery promoted by human was taken,the recovery would reach a better result.     

广西北海红树林土壤放线菌的分离与鉴定

[目的]鉴定广西北海红树林土壤放线菌的物种多样性。[方法]从广西北海红树林土壤中分离、筛选10株典型放线菌菌株,提取基因组DNA,进行16SrDNAPCR扩增与测序,并构建进化树。[结果]通过Blast比对,10株放线菌属于2个属,其中8株为链霉菌属（80%）,2株为拟诺卡氏菌属（20%）。[结论]广西北海红树林土壤蕴藏着种类丰富的放线菌。     

Geographical Distribution of Bacillus thuringiensis Strains and vip3 Genes in Different Climatic Zones in China

Vegetative Insecticidal Proteins(VIPs),a large family of insecticidal proteins,are produced from Bacillus thuringiensis (Bt) during the vegetative growth stage. VIPs represent the second generation of bio-insecticides that confer a wider insecticidal spectrum and have stronger activity.This work compared the geographical distribution of Bt strains and their vip3 genes in different climatic zones in China, the tropical (Hainan Province), subtropical (Guangxi Province) and temperate zones (Heilongjiang Province). A total of 156 Bt strains were isolated from 841 soil samples in Hainan Province tropical region, 356 Bt strains from 1 420 soil samples in Guangxi Province and 167 Bt strains from 1 010 soil samples in different geographical regions in Heilongjiang Province. Twenty-two out of 156 strains from tropical Hainan Province and two out of 356 from subtropical Guangxi Province were found to express vip3 genes,while vip3 genes were not expressed from temperate zone in Heilongjiang Province.Restriction Fragment Length Polymorphism(RFLP)was used to identify different types of vip 3 genes that were within the same family and three full-length vip3 genes were isolated.The genes cloned from Bacillus thuringiensis strain SL3 expressed in the transformed E.coli BL21 strain. Through SDS-PAGE, 88.6 ku insecticidal protein was expressed. The bioassays used two-instar larva of Lepidoptera insects (Spodoptera exigua and Agrotis ipsilon)were performed.The results of the bioassays showed that the protein strongly inhibited the body weight increasement on Spodoptera exigua and Agrotis ipsilon in a standard bioassay.Taken together,the results indicated that the distribution of Bt strains and vip3 genes had regional preference.Tropical and subtropical regions were the rich resources of Bt strains and vip3 genes compared with temperate region.These results would undoubtedly facilitate the studies of insecticidal proteins and expand the list of the pest-killing candidates to make fully use of the extremely rich microbial resources.The new vip 3 genes isolated in the current study might also help resolve the emerging insecticidal resistance problems.     

一株海洋细菌HZBN43的鉴定(英文)

[Objective] The aim of this study is to identify a bacterial strain isolated from ocean water from the Yellow Sea.[Method]Using 16S rRNA technique,a strain from Yellow Sea was preliminarily identified and analyzed.[Result]One 1 521 bp fragment of 16S rRNA was amplified from the strain HZBN43;homology analysis between the yielded sequence and the 16S rRNA sequences accessed in NCBI from other strains showed that HZBN43 belonged to Bacillus,and shared 99.79% homologue with the known species of Bacillus selenatarsenatis.[Conclusion]The sequence of strain HZBN43 was obtained.However,because of the incomplete sequence,the confidence level is just 46,so other corroborations are still required for grouping HZBN43 into an exact species.     

鸡舍环境镰孢菌的定量研究(英文)

[Objective] The aim of this study is to quantitatively analyze the Fusarium concentration and distribution in air and the surrounding substrates(feed,feces,dust,soil)in the chicken house to provide a scientific basis for the control and early warning of Fusarium infection in poultry and practitioners.[Method]Air samples collected by a 6-stage Anderson air microorganism sampler and exposed culture plates as well as substrate samples gathered by aseptic bags were cultured,counted and purified in the lab.[Result]717 strains of Fusarium isolates were obtained and the dust had the highest Fusarium concentration among the samples(2.8×105-1.5×106 CFU/g with an average of 8.8×105 CFU/g).[Conclusion]The Fusarium distribution in the air was in high correlation with those in soil and dust.     

西瓜枯萎病土壤拮抗菌的筛选(英文)

[Objective] The aim of this study was to screen bacteria strains with stable antagonistic effect against watermelon fusarium wilt from soil and investigate the biological control of watermelon fusarium wilt by applying the antagonistic bacteria strains into soil.[Method] Actinomycete strains,fluorescent bacteria strains and bacillus strains were isolated from soil samples by the dilution-plate method,then its resistance was screened respectively by the improved confront culture method after colonies were purified.Finally,bacteria strains with better antagonistic effect were identified.[Result] 29 bacteria strains with stable antagonistic effect against watermelon fusarium wilt were screened from 39 soil samples,which contained 15 fluorescent bacteria strains,5 bacillus strains and 9 actinomycete strains.Furthermore,three antagonistic bacteria strains of FM2,FM3 and FM4 with the strongest antagonism were identified primarily.[Conclusion] According to cultural characteristics,morphological observation,biochemical and physiological tests,FM2 belongs to bacillus subtilis,while FM3 and FM4 belong to micrococcus.     

Effects of Vegetation Succession on Soil Fertility Within Farming-Plantation Ecotone in Ziwuling Mountains of the Loess Plateau in China

To further understand the relationship between vegetation succession and soil fertility within farming-plantation ecotone in Ziwuling Mountains of the Loess Plateau, nine kinds of widely distributed communities at different succession stages were selected, and the effects of vegetation succession on soil fertility were studied through the methods of comparing two hierarchical clustering （similarity index： B） and other multivariate analysis. The results showed that： （i） the similarity in clustering pattern of nine communities which classified by plant species and soil nutrients respectively showed a trend of B ^-overall plant-soil0-10cn〉B^-overall plant-soil 10-20 cm 〉B^- overall plant-soil 20-40 cm, and for the top soil, it showed a trend of B^- grass-soil 0-10 cm 〉 B^-shrub-soil 0-10 cm 〉 Btree-soil0-10 cm; （ii） soil fertility increased during the succession process from abandoned land to forest community, and the soil fertility of forest community showed an increased order of coniferous forest →mixed forest →broadleaf forest; （iii） during the process of vegetation succession, the variation of topsoil fertility was higher than that of the subsurface soil （coefficient of variation： CV0-10 cm 〉CV 10-20 cm 〉 CV20-40 cm）, and when the succession developed into the stages of shrub and forest communities, the top soil fertility had been improved significantly; and （iv） for the subsurface soil of the communities at the advanced succession stages, the soil fertility also increased to some extent. Our results suggested that the method of comparing two hierarchical clustering reflected the similarity level of different cluster patterns, therefore, it was helpful to study the relationship between vegetation succession and soil fertility. There was a corresponding relationship between the change process of soil fertility from the top soil to subsurface soil and the process of vegetation succession from the early stages to the advanced stage. The differentiations of soil fertility in vertical space and horizontal space were both caused by vegetation succession, which was significant for both the shrub and forest communities. The improved level of forest soil fertility was related to forest vegetation types and the improved fertility level of broad-leaved forest-soil community was higher than that of the coniferous forest soil. In the practice on soil fertility ecological restoration of the loess plateau, it is important to carry out reasonably artificial forestation so as to enhance the restoration and improvement of soil fertility.     

Regional Variability of the Effects of Land Use Systems on Soil Properties

In order to explore the regional variability of the effects of land use systems on soil properties, Shouyang County in Shanxi Province and Danling County in Sichuan Province of China were selected as the study areas. Field soil samples of the four land use systems （natural forest, forest plantation, shrubland, and cropland） were collected, respectively, from the two areas. The general statistical tools were used to analyze soil data. The results showed that the influence of land use systems on soil properties was significant. In general, soils in slightly human-disturbed land use systems presented a higher fertility level than those in strongly human-disturbed land use systems in both areas. Furthermore, the impacts of the same land use systems on soil properties showed a distinct regional variability, and even in the same land use system, different farming systems and site management measures （such as irrigation, fertilization, and pesticides） could also lead to the regional heterogeneity in soil properties. The regional variability of land use effects on soil properties reveals the regional variability of the effects of human activities on environmental changes, and could explain the complex relationship between humans and the natural environment in certain ways.     

Evaluation of Soil Fertility Suitability of Yiliang Fobacco-growing Areas in Yunnan Province

[Objective]This study was conducted to evaluate the soil fertility in Yiliantobacco-growing areas of Hunan Province.[Method]The soil nutrient contents iseven tobacco-growing towns of Yiliang County,Yunnan Province were surveyefrom 2010 to 2013 and integrated soil fertility index（SFI value）was calculated tanalyze the soil fertility suitability in theses areas.[Result]The soil p H,contents oorganic matter,hydrolytic N,rapidly available K and available B were all at an appropriate level,while the contents of rapidly available P,available Mg,available Zand water-soluble Cl-were high.Among them,the contents of available P and water-soluble Cl-had great variation.Finally,the soil fertility suitability of Yiliang tobacco-growing areas was graded based on their SFI values.As a result,20%of thestobacco-growing areas were in Grade I,47.7%in Grade II,29.3%in Grade III1.5%in Grade IV and 1.5%in Grade V.The average SFI was 0.61.From 2010 t2013,the p H value and available Mg content reduced year by year,while the contents of organic matter,hydrolytic N,rapidly available P,rapidly available K,available Zn,available B and water-soluble Cl-were increased.     

Phosphorus Status and Risk of Phosphate Leaching Loss From Vegetable Soils of Different Planting Years in Suburbs of Changsha,China

The aim of the study was to develop an index to assess the environmental risk of P loss potential in vegetable soils with chronic difference of plantation in the suburbs of Changsha, Hunan Province, China. Chemical methodology was used to study soil phosphorus status and the relationships between available P in soil and potential soil leaching P. The results showed that there was a significant linear relationship between Olsen P and CaC12-P or P concentration in soil solution. Olsen P increased sharply when either CaCI2-P or P concentration in soil solution reached a certain level. It was confirmed that 80 mg kg-t of Olsen P was the critical value of soil P leaching in the vegetable soils. P leaching probability over the critical was assessed by GIS and indicator Kriging and four secondary risks of phosphorus leaching loss were defined. In the area with vegetable cropping for over 30 yr （Chenjiadu） and 10-15 planting years （Huangxingzhen）, the indices of phosphorus leaching loss risk were 3 and 2.93, respectively. These two areas belonged to strong secondary of risk of phosphate leaching loss. In the new vegetable planting field less than 2 yr （Ningxiang）, the index was 0.06, which had almost no risk of phosphorus leaching. In vegetable soils in the suburban region of Changsha, the phosphorus leaching peotential is high and the phosphorus leaching loss is related to chronic length of vegetable cropping.     

猪粪中高温纤维素分解菌的分离、筛选和鉴定

[目的]为研制高效生物降解菌剂奠定基础.[方法]在60℃条件下对猪粪中纤维素分解菌进行了分离研究,对分离到的菌株进行羧甲基纤维素酶活(CMCase)和滤纸酶活(FPase)测定,并进行16S rRNA基因分析.[结果]BC1和BC3号菌株CMCase、Fpase都较高,但相差不大,通过16S rDNA序列分析发现BC1和BC3号菌株分别与Pseudomonas sp.的相似性达到98%和99%.[结论]该研究为研制高效生物增温剂奠定了基础. Abstract： [Objective] The research aimed to lay the foundation for high-efficiency biological degradation microbial inoculums.[Method]under the 60℃ temperature the cellulolytic microbes in pig manure were isolated and determined the CMCase and Fpase,then proceeded the 16S rRNA gene analysis. [Result] The results showed that:BC1 and BC3 strains characterized higher carboxymethyl cellulose enzyme activity and higher filter paper activity,but their difference was small,then the 16S rDNA sequence of BC1 and BC3 strains were related to pseudomonas sp.(98% and 99% similarities,respectively).[Coaclusion]the experiment laid foundation for high-efficiency biological heating agent.     

一株产紫杉醇的曼地亚红豆杉内生真菌的分离及鉴定

[目的]分离并鉴定1株产紫杉醇的曼地亚红豆杉内的内生真菌.[方法]从曼地亚红豆杉树皮内表皮中分离得到32株内生真菌,并通过高效液相色谱法检测其发酵产物.[结果]筛选获得1株可以产紫杉醇的内生真菌M57,其紫杉醇产量为45～50μg/L,并通过对M57菌落的形态学观察以及18S rDNA序列分析初步将其鉴定为根霉属(Rhizopus)真菌.[结论]该菌株的发现为微生物发酵法生产紫杉醇提供了具有潜在应用价值新的菌种. Abstract： [Objective] The aim was to isolate and identify a taxol-producing endophytic fungus from Taxus media.[Method]32 strains of endophytic fungi were identified form the inner bark of T.media,and their fermentation products were detected by high performance liquid chromatography (HPLC). [Result] Through the screening,a strain of taxol-producing endophytic fungi M57 was obtained,which could produce 45-50 μg/L of taxol,and M57 was defined as Rhizopus sp.through morphological observation and 18S rDNA sequence analysis. [Conclusion] The finding of Rhizopus sp.M57 provided a promising strain for producing taxol with taxol-producing fungi fermentation process.     

牛体外发育胚胎特定阶段差异表达基因的研究

[目的]研究不同发育时期牛体外受精胚胎在基因表达模式上的差异.[方法]利用单个胚胎mRNA差异显示技术,对单个8细胞期胚胎与囊胚进行mRNA差异显示,获得1条特异表达条带,对其进行克隆、测序,并与GenBank进行对比.[结果]该序列与牛核糖体蛋白131基因(ribosomal protein 131,RPL3])具有99%的同源性.采用实时定量PCR技术检测8细胞期和囊胚期胚胎RPL31的mRNA表达量,结果表明,RPL31在8细胞期胚胎的相对表达量为囊胚期胚胎的3.2倍.[结论]为揭示和阐明控制牛早期胚胎发育的相关机理提供依据. Abstract： The cattle different stage embryos obtained from in vitro was studied using the technology of single preimplantation embryo mRNA different display:single 8-cell and blastocyst stage embryos were studied using technology of mRNA different display and one different fragment was found.The result suggested that this fragment displayed high homology (99%) to cattle mRNA for ribosomal protein L31.Then to detect the expression of RPL31 mRNA in 8 cell and blastocyst stage embryos by real-time quantitative PCR,the result showed the relative amount of 8 cells was 3.2 times of blastocyst's.     

抗黄瓜花叶病毒RNAi载体的构建及烟草的转化

[目的]构建抗黄瓜花叶病毒RNAi载体,并将载体转入烟草.[方法]采用RT-PCR方法,扩增黄瓜花叶病毒NS04加工番茄分离物的RNA2基因组的序列选取CMV RAN2基因组中的复制酶片段作为靶序列,构建pBi35SCR2真核表达载体,并对表达载体时行鉴定;通过农杆菌介导的方法将表达载体转入烟草,用PCR的方法检测载体是否转入.[结果]系统进化树分析结果表明,RNA2中编码CMV-2a的序列与中国浙江的DQ412731 分离物有较高核苷本乡酸及氨基酸同源性,分别达到98.0%和96.5%;RCR结果表明,试验成功构建了pBi35SCR2真核表达载体,并成功将表达载体转入烟草[结论]试验获得的转基因烟草可作为后期攻毒试验的材料,并为研究加工番茄抗黄瓜花叶病毒奠定了基础. Abstract： [Objective] Aimed to construct RNAi vector resistant to cucumber mosaic virus and transferred this vector into tobacco.[Method]RT-PCR method was used to amplify cucumber mosaic virus NSO4 and process RNA2 gene sequen of tomato isolates.The analysis results of phylogenetic tree demonstrated that the sequence in RNA2 encoded CMV-2a had 98.0% and 96.5% homology with nucleotide and amino acid of DQ412731 isolate of Zhejiang,China.The replicase fragment in CMV RAN2 gene was taken as target sequence to construct pBi35SCR2 eukaryotic expression vector,then the expression vector was identified.Through agrobacterium-mediated method,the expression vector was transferred into tabacco and PCR method was used to check the transfer.The PCR results demonstrated that the experiment had successfully construct eukaryotic expression vector of pBi35SCR2 and the expression vector was successfully transferred into tabacco. [Conclusion] The obtained transgenic tobacco could be used as challenge test material in following experiment and provided foundation for studying processing tomato resist cucumber mosaic virus.     

底栖鱼类对水田上覆水中磷素动态的扰动效应

[目的]研究底栖鱼类泥鳅对水田上覆水中磷素动态的扰动效应,探讨生物扰动机制.[方法]基于模拟试验,使用离子色谱法和分光光度法,对比分析上覆水中磷素含量在有/无泥鳅活动时的差异.[结果]扰动组的TP、DTP和PP浓度在试验开始阶段与对照组无显著差异,在试验中、后期显著高于对照(P<0.05).扰动组要的PP/TP高于对照组,扰动组中TP浓度的增加主要是由于PP的增加,扰动组的DIP/DT在试验中、后期显著高于对照(P<0.05).[结论]底栖鱼类对水田上覆水中的磷素产生了扰动作用,增加了水稻生长可利用的的磷素养分. Abstract： [Objective] The research aimed to investigate the bioturbation effects of benthic fish Misgurnus anguillicaudatus on phosphorus dynamic in overlying water of paddy field,as well as to explore the bioturbation mechanism.[Method]Based on simulation experiment,the phosphorus contents in overlying water were analyzed comparatively with and without Misgurnus anguillicaudatus by the using of ion chromatography and spectrophotometry. [Result] The concentrations of total phosphorus (TP),dissolved total phosphorus(DTP)and particular phosphorus(PP) in bioturbation group had no significant differences with those in control group in initial stage of experiment,and became significantly higher than control group in middle and late stages of experiment(P<0.05).The PP/TP ratios in bioturbation group were bigger than those in control group,the increase of TP concentration in bioturbation group was mainly due to the increase of PP.The ratios of dissolved inorganic phosphorus(DIP) to DTP (DIP/DTP) were significantly bigger than those in control group in middle and late stages of experiment (P<0.05). [Conclusion] The benthic fish had bioturbation effects on phosphorus in overlying water of paddy field,which increased the available phosphorus for rice growth.     

基于蒙特卡洛多重积分的DNA动力学结构参数的计算

依据最新NDB数据库中蛋白质-DNA复合物晶体结构数据,基于修正的DNA结构统计力学模型,利用蒙特卡洛多重积分计算DNA动力学结构的有关参数,并对计算得到的结果进行时间复杂度和精确度分析. Abstract： Based on protein-DNA complex crystal structural data in up-to-date Nucleic Acid Database,the related parameters of DNA Kinetic Structure were investigated by Monte-Carlo Multiple Integrals on the base of modified DNA structure statistical mechanical model,and time complexity and precision were analyzed on the calculated results.     

用最短路径传递共表达预测拟南芥基因功能

提出基因之间传递共表达可作为一个重要因素来连接同一代谢通路中的基因,而同一代谢通路中的功能相似的基因都是高表达相关的.因此可通过求代谢通路下的最短路径,南同在一条最短路径上的与未知基因高表达相关的已知基因来预测末知基因的功能.通过用最短路径算法分析拟南芥代谢通路下的共表达数据对未知基因的功能进行预测,证明了此方法可以预测出拟南芥代谢通路下未知基因的功能,并验证了通过在代谢通路下求最短路径来预测基因功能的方法具有一定的可行性和有效性. Abstract： The present paper predicted the function of unknow genes by analyzing the co-expression data of Arabidopsis thaliana from biological pathway based on the shortest-path algorithm.This paper proposed that transitive co-expression among genes can be used as an important attribute to link genes of the same biological pathway.The genes from the same biological pathway with similar functions are strongly correlated in expression.Moreover,the function of unknown genes can be predicted by the known genes where they are strongly correlated in expression lying on the same shortest-path from the biological pathway.Analyzing the Arabidopsis thaliana from the biological pathway,this study showed that this method can reliably reveal function of the unknown Arabidopsis thaliana genes and the approach of predicting gene function by transitiving coexpression in shortest-path is feasible and effective.     

催产素在广西本地水牛下丘脑-垂体-卵巢轴的免疫组化定位

[目的]研究催产素(OT)在广西本当水牛下丘脑、垂体及卵巢的分布上的联系,进而了解OT在下丘脑、垂体及卵巢3者之间分泌释放途径.[方法]采用免疫组织化学SuperPicTureTM二步法检测5头广西本地水牛的下丘脑、垂体和卵巢中催产素(OT)的分布情况.[结果]下丘脑中分泌OT的神经元主要分布在弓状核、视上核及室旁核,在腹内侧核、腹外侧核、交叉上核、背内侧核、乳头体、下丘脑前核等核团也有一定数量的阳性神经元;在腺垂体发现OT免疫反应阳性产物,自垂体柄和正中隆起的一侧可见到平行排列的OT阳性神经纤维断续地延伸至神经部;卵巢中只在生殖上皮、卵泡颗粒细胞和黄体细胞发现有大量OT免疫阳性产物.[结论]首次发现OT存在于广西本地水牛下丘脑-垂体-卵巢轴的各个环节,并且下丘脑中各主要核团均有OT免疫阳性神经元的分布,尤其以弓状核、视上核、室旁核分布最多,为进一步研究OT的合成和作用机制提供形态学依据,并对广西本地水牛的繁殖育种及泌乳起到一定的参考指导作用. Abstract： To study the association of oxytocin (OT)'s distribution in hypothalamatic,pituitary and ovary,and understand how the OT secrete releasing in hypothalamus,pituitary and ovaries,the paraffin section immunohistochemistry SuparPicTureTM two step method was used to detect the distribution of OT in hypothalamatic-pituitary-ovary axis of five femal Guangxi local buffalo.The test results could provide morphology according to study the OT's synthesis and mechanism of action ,and could play reference and directions part in breeding Guangxi local buffalo.The test results display:oxytocin immuno reactive (OT-IR) neuronsw eremainly distributed arcuate nucleus,supraoptic nucleus and paraventricular nucleus,and OT-IR neurons was also found in ventrornedial nucleus,ventrolateralis nucleus,suprachiasrnaticus nucleus,dorsomediai nucleus,mamillary body,anterior hypothalamic nucleus and so on.The OT immunoactive production was found in pituitary and few OT-IR nerve fibers extended to post pituitary from hypophyseal stalk and medium eminence.In ovaries,OT immunoactive productions were only distributed in germinal epithelium cells,granulosa cells and lutein ceils.The OT was first discovered in singulorum link of hypothalamatic-pituitary-ovary axis of Guangxi local buffalo.The OT immunoactive neurons were first discovered in every main nucleus of Guangxi local buffalo hypothalamus,especially distributed in arcuate nucleus,supraoptic nucleus and paraventricular nucleus.     

干旱胁迫对苗期甘蔗叶片水分和叶绿素荧光参数的影响

[目的]研究干旱胁迫对甘蔗叶片水分和叶绿素荧光参数的影响,为甘蔗生产及评价研究提供依据.[方法]选取7个抗旱性不同的甘蔗品种,在苗期进行干旱胁迫,并测定胁迫条件下甘蔗叶片水分含量和叶绿素荧光参数的变化.[结果]甘蔗叶片水势和相对含水量与土壤相对含水量存在一定的内在联系,耐旱强的品种对土壤水分的利用率较高;相关分析和因子分析表明茁期干旱存活率、Fc/Fm、叶片水势和相对含水量可被用作抗旱性评价指标.[结论]水势表现为一个相对独立的影响因子,对甘蔗抗早性有支配作用,并验证了Fv/Fm作为甘蔗抗旱评价指标的可靠性. Abstract： [Objective] The aim was to explore the effects of water stress on leaf water and chlorophyll fluorescence parameters of sugarcane seedling,as well as to provide basis for the study on sugarcane production and evaluation.[Method]Seven different sugarcane varieties were studied at the seedling stage under drought stress,and the changes of leaf water and chlorophyll fluorescence parameters under stress conditions were detected. [Result] leaf water potential,leaf relative water content and soil relative water content showed a certain amount of internal relationship,the sugarcane varieties that had more tolerant to drought had higher utilization rate of soil water;the correlation analysis and factor analysis suggested that the survival rate at seedling stage under drought stress,Fv/Fm,leaf water potential and relative water content could be used as drought resistance evaluation indicators. [Conclusion] As a relatively independent influencing factor,water potential had dominating effect on drought resistance,and the reliability of Fv/Fm as drought resistance evaluation indicator had been verified.     

中草药提取液对黄瓜苗期杀根结线虫的活性研究

[目的]研究中草药提取液对黄瓜苗期杀根结线虫的活性.[方法]利用植物水培技术,结合生长条件易控制、根系生长过程易连续观察的特点,应用5种具有较强室内触杀根结线虫活性的植物提取液及其与阿维菌素的复配液,对黄瓜苗期水培根系杀线活性进行系统研究.[结果]胡黄连和石榴皮提取液可以在不影响水培黄瓜苗期植株生长的前提下表现出对根结线虫良好的活体植株根系寄生防治和杀灭活性,且达到了与阿维菌素相近的作用水平;而狗脊、木香和蛇床子提取液对黄瓜的生长表现出不同程度的抑制作用,其对根结线虫的防治效用和杀灭活性也较弱.[结论]触杀效果和杀线活性成分能否被植物吸收利用共同制约着具有杀线活性中草药提取液的开发应用. Abstract： Present mature plants hydroponic technology was used,combined with some excellent characteristics,such as growth conditions was easy to control and process of root growth was easy to continuously observe,the nematicidal activity of 5 kinds of Chinese herbs extracts and the compound solution of Avermectin,with strong contact toxicity effect indoor,was systematically studied and investigated the affection on the rootknot nematode parasitized on the cucumber seeding stage.It is found that under the premise of no influence on root growth of cucumber,extracts from Picrorhiza scrophulariiflora and Punica granatum showed strong prevention and nematicidal activity,and had the similar efficacy of Avermectin;while the extracts from Cibotium barornetz,Aucklandia lappa Decne and Fructus cnidii showed low nematicidal activity and various degrees inhibition effect on plant growth.