民勤绿洲边缘区不同生境沙拐枣种群特征研究

沙拐枣（Calligonum mongolicum）是分布于中国北方干旱荒漠区的一种主要固沙植物,研究沙拐枣种群在沙漠不同生境中的群落特征、空间分布格局及幼苗更新,对绿洲边缘区的生态恢复和重建具有重要的意义。本研究以石羊河流域下游民勤沙井子荒漠绿洲过渡带为研究区域,采用野外调查与室内测定相结合的方法,对3种不同地貌类型（半固定沙丘、流动沙丘、丘间地）和6种微地型（半固定沙丘迎风坡、顶部、背风坡和流动沙丘迎风坡、顶部、背风坡）沙拐枣种群特征、更新苗的数量特征与土壤水分的对应关系及分布格局进行了调查分析。结果表明：（1）沙拐枣种群密度、覆盖度表现为：半固定沙丘〉丘间地〉流动沙丘,半固定沙丘和丘间地与流动沙丘之间存在显著差异（P〈0.05）,株高在流动沙丘最大,丘间低地最小,它们之间存在显著差异（P〈0.05）;而种群地径、新梢长无显著差异（P〈0.05）。（2）流动沙丘各部位密度、株高、覆盖度差异不显著（P〈0.05）,而半固定沙丘则表现为差异性显著（P〈0.05）,顶部大于迎风坡和背风坡。（3）不同立地条件下,沙拐枣幼苗数量为流动沙丘〉半固定沙丘〉丘间地,且与5~30 cm土壤水分含量大小相对应。（4）在民勤荒漠绿洲过渡带,沙拐枣种群呈聚集分布。     

沙葱乙醇提取物对肉仔鸡生产性能的影响

试验选择120只1日龄罗斯308商品肉鸡随机分为4个处理组,每个处理3个重复,每个重复10只鸡。对照组饲喂基础日粮,试验组分为AWEⅠ组、AWEⅡ组和AWEⅢ组,分别在基础日粮中添加100、300和500 mg/kg沙葱乙醇提取物(AWE),研究其对肉仔鸡生产性能的影响。结果表明,沙葱乙醇提取物对肉仔鸡生产性能无显著影响(P0.05),但有促进日增重、提高采食量及降低料肉比等指标的趋势。     

Ecological Wood Adaptation and Horizontal Variations of Vessel Element and Fibre Length of Calligonum mongolicum

INTRODUCTION The larger genus in Polygonaceae is Calligonum, which includes about 100 species of shrubs that grow in central Asia. It is well suited to arid climates with drought resistance, and grows more on clay, sandy and gravel grounds. These plants are often cultivated as ornamentals and a stabilizer of mobile sand dunes. There was published information on the wood anatomy of all the examined genera in Polygonaceae (Ma 1994), but the selected species have not yet been described. Ad…     

蒲公英染色体核型分析

蒲公英的染色体核型国内一直未见报道 ,通过对其中期染色体形态的研究 ,得知其核型为 2n =2M 1 6m 4sm 4st=2 6。     

珍贵野生蔬菜蒲公英的有效成分与药理作用

蒲公英中含有胡萝卡素类、三萜类、植物甾醇类、倍半萜内酯类、香豆素类、黄酮类、酚酸类物质；药理研究证明蒲公英具有抑菌、抗内毒素、健胃、利胆、通乳和抗肿瘤等作用。     

河西走廊荒漠绿洲过渡带沙丘不同生境沙拐枣种群扩张特征研究

本研究以河西走廊荒漠绿洲边缘关键天然固沙植物沙拐枣为研究对象,对流动沙丘、固定沙丘不同生境的沙拐枣种群扩张特征进行调查,旨在更全面地认识其种群扩张特征和对干旱高温环境的适应对策。结果表明：（1）沙丘不同生境,沙拐枣种群扩张方式存在显著差异：在流动沙丘,丘间低地和过渡带以有性繁殖为主,无性繁殖为辅;迎风坡和背风坡以无性繁殖为主;而随着流动沙丘固定,种群以有性繁殖为主,无性繁殖数量和所占比重显著下降,并导致种群数量下降。（2）不同生境中沙拐枣种群密度与年龄均呈显著负相关,种群以幼龄苗为主,种群最大年龄出现在丘间低地,为36龄。（3）流动沙丘不同生境根状茎主要为2年生,多年生根状茎长度较短;而固定沙丘不同生境根状茎年龄结构较为均衡。     

HPLC谱法测定蒲公英不同器官中绿原酸的含量

[目的]建立HPLC法测定蒲公英不同器官中绿原酸含量的方法。[方法]采用Shim-pack VP-ODS（4.6 mm×150.00 mm,5μm）色谱柱;以甲醇-0.4%磷酸水溶液为流动相进行梯度洗脱;流速为1.0 ml/min,检测波长为326 nm;柱温为40℃;进样量为20μl。[结果]绿原酸的线性范围为0.791 20~79.120μg/ml,（r=0.999 8）,回收率为98.00%~101.5%。蒲公英叶、根、花和花茎中绿原酸含量分别为1.212、0.536、0.448、0.417 mg/g。[结论]该研究为蒲公英中绿原酸含量测定提供了一种快速、准确的方法;蒲公英叶中绿原酸含量最高,这为更好地开发利用蒲公英这一药食植物资源提供了依据。     

Can alternating temperatures be used to estimate base temperature for seed germination?

Modelling weed seedling emergence pattern appears to be a promising approach in the development of effective weed management programmes based on the selection of optimal timing of control operations. Thermal and hydrothermal time models propose that seed germination rates are proportional to the amount by which temperature and water potential exceed threshold values for these environmental factors. Hence, base temperature for seed germination is a fundamental biological parameter for the prediction of weed emergence. A series of laboratory experiments were conducted to estimate base temperature in three weed species belonging to the Asteraceae family, predominant in conservation tillage fields in north‐eastern Italy. The traditional method based on germination assays at constant temperatures was compared with a method based on assays at alternating temperatures. The latter might represent an alternative to the former for those species which do not germinate or only poorly under constant temperatures. Base temperature was estimated by regressing the reciprocal of the median germination time on temperature comparing two functions, a broken‐stick and an exponential‐type model. Both models showed good fit to all data in the whole temperature range and in almost all cases provided similar estimates of base temperature. The main result is that, for the weed species examined in this study, the use of alternating temperatures for base temperature estimation appears to be possible. However, further research is required to test if the use of germination assays performed at alternating temperatures can be a suitable method to estimate base temperature of species that have too low germination at constant temperatures.     

橡胶草种质苗期农艺性状相关性及遗传多样性初析

利用数理统计软件对12份橡胶草种质材料的主要农艺性状进行相关性、遗传多样性及聚类分析。结果表明:12份橡胶草种质主要农艺性状存在较大差异,其中叶片长、叶片宽、叶形指数、叶柄长变异系数均较大,Shannon-weaver多样性指数H′在1.86~1.99,具有丰富的多样性;叶片长、叶缘类型与其它性状之间相关性较大,其中叶片长与叶片宽、叶形指数、叶柄长及叶缘类型均呈显著正相关;叶缘类型与叶片长、叶片宽、叶柄长均呈显著正相关,与叶脉颜色呈极显著负相关;通过聚类分析将12份材料划分为3个类群,综合评价发现,Ⅱ类群的3份材料(206-1、208-1、214-1)表现显著优于Ⅰ和Ⅲ类群,可作为橡胶草育种的优选材料。     

不同碳源及氮源对钉子菇菌丝生长的影响

【目的】探讨不同碳源及氮源物质对钉子菇菌丝生长的影响效应。【方法】以钉子菇菌株J-4为供试材料,以菌丝生长速率及气生菌丝的长势为指标,考察10种碳源及20种氮源物质对钉子菇菌丝生长的影响。【结果】钉子菇具有较广的碳源及氮源谱,在10种碳源中,对菌丝生长效果较好的碳源有可溶性淀粉、麦芽糖和蔗糖,其菌丝生长指数分别为4.28,2.76和2.04。在20种氮源中,对菌丝生长效果较好的氮源有牛肉膏、酵母膏和牛肉蛋白胨,其菌丝生长指数分别为6.432,5.440和5.436;钉子菇对复合氮源利用效果较好,对无机氮和氨基酸类氮源利用效果较差。【结论】钉子菇的最佳碳源和氮源分别为可溶性淀粉和牛肉膏。