Partial Characterization of Chitinolytic Extract from Endophytic Streptomyces sp. and Its Effects on the Boll Weevil

The present study achieves the biochemistry partial characterization of the chitinolytic extract produced by an endophytic Streptomyces sp. strain （A8）. This extract was also tested against Anthonomus grandis, the cotton boll weevil aiming its control. The chitinase crude extract from the A8 strain was cultured for five days in a minimum liquid media supplemented with chitin. The extract was partially characterized by standard methods. The chitinolytic extract had an optimum temperature of 66 ＂C and an optimum pH between 4 to 9 （around 80% of relative activity）. We also characterized the temperature and pH stability and measured the effects of enzyme inhibitors. The filtered chitinolytic extract was added to an artificial boll weevil diet. Boll weevil development from the egg stage to the adult stage was prolonged, and the percentage of adults that emerged was approximately 66% less than on control diet. This study showed that the.larval development of A. grandis was inhibited by the presence of characterized chitinolytic extract in artificial diet. This work provides an experimental basis for using the chitinase from an endophytic bacterium Streptomyces sp. as a biocontrol alternativeto controlling the plant pest A. grandis.     

Verbascoside isolated from Tectona grandis mediates gastric protection in rats via inhibiting proton pump activity

Evidences have suggested that Tectona grandis (TG) attenuates gastric mucosal injury; however its mechanism has not yet been established. The aim of present study was to evaluate the gastroprotective mechanism of ethanolic extract of TG (E-EtOH), butanolic fraction (Fr-Bu) and to identify its active constituents. Anti-ulcer activities were evaluated against cold restraint (CRU) and pyloric ligation (PL) induced gastric ulcer models and further confirmed through H⁺ K⁺-ATPase inhibitory activity. Cytoprotective activity was evaluated in alcohol (AL) induced gastric ulcer model and further through PGE₂ level. E-EtOH and Fr-Bu attenuated ulcer formation in CRU. Moreover E-EtOH and Fr-Bu displayed potent anti-secretory activity as evident through reduced free acidity and pepsin activity in PL, confirmed further by in vitro inhibition of H⁺ K⁺-ATPase activity. In addition cytoprotective potential of E-EtOH and Fr-Bu were apparent with protection in AL model, increased PGE₂ content and enhanced mucin level in PL. Phytochemical investigations of Fr-Bu yielded terpenoides and a phenolic glycoside, verbascoside. The anti-secretory mechanism of verbascoside mediated apparently through inhibition of H⁺ K⁺-ATPase with corresponding decrease in plasma gastrin level, is novel to our finding. Gastroprotection elicited by TG might be through proton pump inhibition and consequent augmentation of the defensive mechanism.     

香榧和山核桃中铅含量水平及富集原因分析

在浙江香榧和山核桃生产基地、超市和农贸市场实地抽样检测,对数据进行统计分析,研究浙江省香榧和山核桃中铅含量水平。香榧有效样本数158个,铅含量平均值0．113mg／kg,符合NY5324--2006（（无公害食品常绿果树坚果》标准要求（铅≤0．2mg／kg）,含量范No．034～0．382mg／kg;山核桃有效样本数216个,铅含量平均值0．211mg／kg,符合NY5307--2005《无公害食品落叶果树坚果》标准要求（铅≤0．4mg／kg）,含量范围0．013—0．409mg／kg。     

湖南地方柚资源及其近缘种多样性的SRAP分子评价

以湖南本地柚类资源为试材,应用SRAP标记对41份柚类资源及5份近缘种的遗传多样性进行分析与鉴定。结果表明:平均每个引物组合可扩增出16.6条谱带,17对SRAP引物共扩增出283条谱带,其中多态性谱带235条,多态率为83.0%,基因多样度变幅为0.431 7~0.770 0,平均基因多样度为0.544 3;获得了21个基因型的37个SRAP特异性标记,不同引物组合可将42个基因型完全分开;柚类及近缘种等位基因平均数、平均杂合位点占比、SRAP表型杂合度(H0)分别为9.02、67.77%和0.343。聚类分析结果显示,41份柚种质及5份近缘种材料在遗传相似系数0.792处可分为6个组群:第1、2组群分别由24个和11个柚的地方品种构成;第3组群为柚的种间杂种类型,包括菠萝香柚、慈利金香柚、慈利甜柚2号和慈利水柚子;第4组群由慈利柚09–1、金瓜两杂种柚和酸橙、臭皮柑两近缘种组成;第5组群包括无核大红甜橙和温州蜜柑;第6组群为柠檬。综合SRAP标记结果与形态特征分析,认为慈利金香柚可能源于以柚类为母本、以橙类(或宽皮橘类)为父本的自然种间杂交后代。     

不同密度15年生巨尾桉经济生态效益分析

对初植密度为1 665株.hm-2的巨尾桉林分3.5年生进行疏伐,开展4种不同保留密度(600、900、1 200、1 415株.hm-2)林分长周期经营试验。研究表明,15年生时的经济和生态效益优于短周期,年利润比短周期高2.3倍,林下植被正向演替,林分土壤肥力、水源涵养功能比9年生时好或持平;林分平均胸径、单株材积、中大径木比例、规格材比例、净现值和内部收益率、林下植被种类、高度、丰富度、均匀度和多样性指数均随林分保留密度下降而增加,林分总出材量、经营利润、土壤肥力、水源涵养功能均以保留密度为1 200株.hm-2的林分最高。据此提出在福建省可试行改变短周期定向培育为长周期多目标培育的思路,且保留密度以小于1 200株.hm-2为宜。     

An explicit stem profile model for forked and un-forked teak (Tectona grandis) trees in West Africa

Studies on stem profile of teak (Tectona grandis) hardly exist. This can be possibly attributed to the occurrence of forks that is prevalent on teak trees. Stem profile model was therefore developed for teak in West Africa, which took into account the occurrence of forks. Trees were destructively sampled from Moist Evergreen Forest (MEF), Moist Semi-deciduous Forest (MSDF), Dry Semi-deciduous Forest (DSDF) and Savannah ecological zones in both Ghana and Côte d’Ivoire for the study. A single set of parameters could be used explicitly to predict stem profile of any teak tree, irrespective of country, eco-climatic zone, edaphic variables, site index, tree age, stand density and tree competition. The model efficiency and root mean square error (in relative diameter) were calculated to be 0.97 and 0.053, respectively. The relative position of the forks along the stem bole, with respect to total tree height, was highly variable and did not follow any particular trend, except higher value for the first fork in the Moist Evergreen Forest zone. However, average tree height to the first fork decreased along the ecological gradient from MEF, MSDF and DSDF to Savannah. The extent of diameter reduction due to the forks could be predicted. Relative tree form for zero-forked, one-forked and two-forked trees was calculated to be 0.39, 0.36 and 0.33, respectively. Relative loss of stem volume due to one fork and two forks was estimated to be 6.5 and 13.9%, respectively. The measured stem volume when related to the corresponding predicted value yielded coefficient and intercept not significantly different from unity and zero, respectively, with an r² value of 0.97.     

浙江省不同地区香榧生籽营养品质差异性分析与评价

为综合评价香榧营养品质,本试验以浙江省8个不同地区共32份香榧生籽样品为研究对象,对包括宏量营养素、矿质元素及维生素E在内的38项营养品质指标含量进行差异性分析及相关性分析,建立模糊数学综合评价模型以评价其营养品质。结果表明,不同地区香榧营养品质指标含量存在一定差异,宏量营养素中可溶性糖与淀粉的变异系数相对较大,微量营养素中钠的变异系数最大。相关性分析结果表明,脂肪与蛋白质、淀粉间存在较强的负相关,多数氨基酸间表现为极强的正相关,亚油酸与金松酸、硬脂酸与油酸两组脂肪酸在组内具有较强的正相关,组间表现为较强负相关。模糊数学综合评价结果显示磐安县、东阳市与诸暨市3个地区宏量营养素指标评分较高;微量营养素评分较高的为柯桥区、嵊州市与松阳县,整体综合评分在0.403~0.528之间。本研究结果为香榧营养品质评价及产品分级利用提供了研究基础与参考依据。     

柚木离体快速繁殖技术

从优良柚木林段选取3~4a生优良单株,从中选取无病虫害的幼嫩侧芽,经表面消毒后接种到无菌培养基上,侧芽萌发率达70%~80%。切取新芽进行增殖,30~40d为一周期,增殖系数为2~3倍。当侧芽增殖到足够数量时,转移到生根培养基上,生根率超过80%~90%。植株移栽成活率达80%~90%。几个月后植株便可种植到大田。      

肇庆特色柑橘品种汶朗蜜柚品质评价及其相关性分析

[目的]研究肇庆地区特色柑橘品种汶朗蜜柚的果实品质及其与果园土壤养分和叶片矿质营养元素之间的相关性.[方法]测定了汶朗蜜柚果园土壤pH、有机质、N、P、K等矿质元素含量、叶片N、P、K等矿质元素含量和果实可溶性固形物、可滴定酸和总糖等品质指标,并对其相关性进行分析.[结果]果园土壤中富含铁、钙元素,与汶朗地区有丰富的石灰岩、铁矿有一定的关联.叶片及土壤养分与果实品质有一定的相关性,其中果实品质的形成受树体对矿质元素的吸收和利用能力的影响大于土壤中矿质元素含量的影响.汶朗蜜柚果实品质的合成合理-满意度优于沙田柚的,单因素指标的合理满意度分析显示果皮色泽是制约汶郎蜜柚果实品质的一个重要因素,主要表现为果面疤痕.[结论]研究可为进一步探索柑橘营养生理和品质形成规律提供参考依据,并为汶朗蜜柚栽培管理提供参考.     

榧树的资源分布与生态习性

为期5 a的调查研究表明,榧树Torreya grandis的自然分布区在我国的中亚热带和北亚热带,25°~32°N,109°~121°E,跨浙、皖、苏、闽、赣、黔、鄂等7省广大地区。分布区的年均气温为15.2~18.7℃,极端最低气温-17.0~-8.1℃,年降水量1000~1900 mm,≥10℃年积温为4758~5940℃。垂直分布随地理位置而异,在北亚热带的大别山海拔可达800~1100 m,黄山和天目山可达1200~1500 m,中亚热带南部武夷山可达1800~2000 m。在缓风、向阳、少受寒潮危害的高海拔地段,极端最低温-18.0℃,≥10℃年积温3 500℃,榧树生长结果正常。南部武夷山区海拔1800~2000 m,≥10℃年积温仅3200℃,但由于极端最低温较高(-15.0℃以上),榧树呈高大乔木,结实正常。榧树喜肥,在有机质丰富,土壤疏松,质地由砂壤到轻黏,pH 5.2~6.5的土壤中生长发育良好。表3参27