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1.
Factors involved in the establishment of Taraxacum officinale (dandelion) seedlings in grasslands and plant mortality in the first growing season were studied during 2008–2011. The study was conducted at 11 grassland sites that differed in the quantity of seed rain and the intensity of seedling predation by slugs. In April, of each study year, 10 plots open to the sedimentation of naturally dispersed seeds were established at each site, five plots of which were also sown with 250 T. officinale seeds each. The amount of natural seed rain, slug feeding activity and number of plants in each plot were then recorded at monthly intervals. Seed rain and seedling predation accounted for c. 50% of the variation in seedling establishment. Populations of established seedlings then declined through October, at which point they were at 25% of the original abundance on average. The percentage of plants that survived varied among sites and years. The temporal and spatial variation in T. officinale establishment and survival of young plants was enormous, even within a small area. Predation of seedlings by slugs can effectively prevent the establishment of T. officinale in grassland. This only occurred, however, at slug abundances not acceptable under conditions of public access.  相似文献   
2.
根据严重段塞流4个阶段的特点,针对L形立管系统不稳定流建立了一维准平衡态简化计算模型,其忽略摩阻和加速度的影响,立管中气相穿透过程应用漂移流模型。气相穿透、气液喷发阶段采用特征线方法求解,并引入气相密度偏移修正过程,能够对典型严重段塞流和液塞长度小于立管高度的过渡严重段塞流进行模拟。将模型计算结果与实验室结果以及其他文献的实验数据进行对比,结果表明模型能够对L形立管系统中的两相不稳定流动进行较准确的模拟。(图2,表3,参16)。  相似文献   
3.
山楂黄酮提取物降血脂研究   总被引:3,自引:0,他引:3  
[目的]研究山楂黄酮提取物的降血脂作用,为其相关产品开发应用提供依据。[方法]采用渗漉法提取山楂黄酮,对SD大鼠进行试验,待大鼠形成高脂模型后,采用低、中、高剂量灌胃山楂黄酮提取物,30 d后测定大鼠血脂中总胆固醇、甘油三酯、低密度脂蛋白、高密度脂蛋白的变化。[结果]山楂黄酮提取物使各剂量组大鼠血脂中的总胆固醇、低密度脂蛋白含量明显降低,对甘油三脂、高密度脂蛋白有调节作用。[结论]山楂黄酮提取物具有显著的降血脂功效。  相似文献   
4.
为给新疆野生山楂资源的保护与利用提供理论依据和技术支持,采取新疆3种野生山楂共计63份材料,利用ISSR标记技术,对其遗传多样性和亲缘关系进行分析。结果表明,12条引物共扩增出233条带,其中多态性条带221条,多态性位点率为94.4%,平均每个引物获得19.42个扩增带。POPGENE1.32分析结果表明:3种野生山楂材料的多态性位点率、观测等位基因数、有效等位基因数、Nei’s基因多样性和Shannon信息指数,均为准噶尔山楂最高,阿尔泰山楂次之,红果山楂最低。3种新疆野生山楂进行两两比较,其Nei’s遗传相似度为0.862 2~0.904 4,平均值为0.890 2;遗传距离为0.100 5~0.148 3,平均值为0.1166。3种野生山楂中,准噶尔山楂存在较为丰富的遗传变异,其次是阿尔泰山楂,红果山楂的遗传变异较小。阿尔泰山楂和红果山楂的亲缘关系较近;准噶尔山楂和红果山楂间亲缘关系较远。  相似文献   
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6.
用不同剂量多效唑对‘敞口’山植进行土施或叶面喷施,结果表明其可明显抑制新梢生长,节间缩短,节数减少,叶面积减小,而比叶重和叶绿素含量增加。明显促进花芽分化而降低座果率。喷施50 ppm 赤霉素一次,可提高座果率但不消除多效唑对营养生长的抑制作用。处理可使果实变小,果形变扁,对果中糖、酸、果胶和 VC 含量无明显影响。讨论了适宜用量和方法。  相似文献   
7.
核桃红果乳的研制   总被引:3,自引:0,他引:3  
以核桃、红果为主要原料,添加0.45%的复合稳定剂,15%的红果浆,25%的核桃乳,15%的白砂糖和pH值3.0为最佳配方,产品色泽、风味俱佳,组织状态稳定。  相似文献   
8.
新疆野生山楂种子特征及萌发特性研究   总被引:1,自引:0,他引:1  
采集阿尔泰山楂、准噶尔山楂、红果山楂成熟的种子分别采用湿种恒温、变温、外源激素浸泡处理、阴干后层积方法进行层积处理测其种子特征指标及层积后的发芽率,结果表明变温层积对两种山楂种子的萌发有较好的促进作用但不同种山楂种子所需的较适层积时间范围有差异阿尔泰山楂种子层积日90d左右发芽率可达39.5%,红果山楂种子层积150d左右发芽率可达27.1%;准噶尔山楂种子在所有层积处理中的萌发率都相对较低100mg/L的GA3处理层积180d后发芽率为10.2%,三种山楂种子均为自然休眠种子不同层积处理能够打破其休眠促进种子萌发其中变温层积处理效果较好,阿尔泰山楂具有较高的发芽率.  相似文献   
9.
A leaf disc bioassay was employed to investigate the influence of host species of deciduous fruit trees, like apple, peach, plum, cherry and apricot, on the development and reproduction of the hawthorn spider mite Tetranychus viennensis Zacher in the laboratory under conditions of 25±1°C, 60±10% RH and a photoperiod of 16 h: 8 h light: dark. This was done by determining the duration of each life stage of the mites, the intrinsic rate of population increase (r m ), mean generation time (T) and net reproductive rate (R 0) of the spider mites on each of the host plant species. Differences in life table parameters of the spider mite among host plants were analyzed with the jack-knife method. The results indicated that plum might be the best suitable plant for the spider mite among the plants tested due to shorter developmental period and higher intrinsic rate of increase, whereas cherry and apricot were least suitable due to their long developmental duration and low intrinsic rates of increase. When the spider mites were transferred from apple to other fruit trees, negative effects on developmental duration, fecundity and life table parameters were found in the first generation, but the effects faded out in succeeding generations. When transferred onto plum and peach, the spider mite adapted to the new hosts in the second generation; however, on cherry and apricot, it adapted in the third generation. __________ Translated from Acta Ecologica Sinica, 2005, 27(7) [译自: 生态学报, 2005, 27(7)]  相似文献   
10.
Objective To explore and seek the best solution for the suitable high-yield tree shape and planting mode, fertilizer selection, chemical selection and other technologies of Jin Ruyi yellow hawthorn, in order to fully demonstrate the early maturity of Jin Ruyi yellow hawthorn, golden peel, fragrant and sweet flesh, and good fresh food. The advantages of new varieties such as export, Yifengyin, etc., and at the same time obtain the best yield per unit area. Method to carry out high-yield cultivation technology research through different tree shape comparison experiments, planting mode comparison experiments, fertilizer comparison experiments, and chemical comparison experiment analysis. Completion it was concluded that the trunk-shaped high-light-efficiency tree shape was adopted, supplemented by ridge cultivation, determined planting density of 2m×4m, water-saving drip irrigation, application of organic-inorganic compound fertilizer, improved fruit setting rate, and green control of pests and other measures to optimize the configuration technology. The plan can realize the early high yield of Jinruyi yellow hawthorn with high quality and stable yield year after year.  相似文献   
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