2种方法在荒漠草原植物种群分布格局中的适用性比较

研究首次比较了2种方法在测定荒漠草原6种植物种群分布格局中的适用性.结果表明,方差均值比率法及聚集强度指数法中的多个指数都适合于这6种植物分布格局的计算.但其中的聚块性指数法的运算难度较大,宜慎用.比较结果这6种植物种群皆为聚集分布,但聚集程度有所差别.     

限饲模式下宁乡花猪商品猪的生长肥育性能分析

为探索限饲模式下宁乡花猪商品猪生长肥育性能以适应品牌猪肉具备风味性、安全性需要,在初生重(0.98±0.02)kg饲养(99.69±2.48)d的基础上,相应于25~35 kg、35~60 kg、60~75 kg等3个体重阶段,采用精料重分别占90%、80%、70%,青料重分别占10%、20%、30%配制饲粮,并按8.5成饱模式饲喂。结果表明:1)试猪由体重(24.79±0.64)kg饲养至出栏日龄(243.77±2.67)d、出栏体重(78.22±1.76)kg,该生长肥育全程(144.03±0.23)d、日增重(370.50±9.50)g、料重比(3.51±0.03),充分体现出限饲模式可行性;2)在≤240 d、240~260 d、>260 d的日龄梯级下分别以初生重(1.02±0.02)kg、(0.94±0.04)kg、(0.99±0.08)kg所求取的日增体重百分率曲线与日龄梯级呈负相关态势,显现日龄低梯级明显优于高梯级,反映出生长强度与日龄负相关的必然性;3)自起运至屠宰分别间隔5 h、29 h的胴体率、白条率的相差值达5.04和5.05个百分点,屠宰间隔直接造成胴体损失。     

金玉818青贮玉米接茬花溪芜菁甘蓝种植模式研究

为了提高土地复种指数,增加贵州省大方县农民收入,进行了金玉818青贮玉米接茬花溪芜菁甘蓝的种植模式研究。研究结果表明,该种植模式在大方县的种植效果较好,其纯收入可达到27517.50元/hm2。     

浙江省山药资源开发利用现状及其发展前景

山药在我国栽培历史悠久,既是食用的滋补保健佳品,又是常用的药材。对浙江山药资源的利用现状和存在的问题进行了阐述,并从山药的菜用、药用和国内外市场等方面的前景进行预测分析,提出浙江山药产业发展的6点对策。     

Changes of BMP signaling pathway in mammary glands of mice with mammary hyperplasia

AIM: To determine the expression patterns of bone morphogenetic protein (BMP) signaling components in the mammary glands with hyperplasia (MGH) and the activation of this signaling pathway. METHODS: The female C57BL/C mice (8-weeks-old) were randomly divided into control group and hormone group with 15 mice in each group. The mice in control group were treated with PBS, while the mice in hormone group were intragastric administration with estradiol valerate (2.5 mg/kg) for 25 d, followed by progesterone (4 mg/kg) peritoneal injection for 5 d. At the end of treatments, the mammary glands were collected to determine the morphological changes, the mRNA expression of BMP signaling components and the phosphorylation level of Smad1/5/9. RESULTS: In MGH, a part of BMP signaling pathway molecules were differentially expressed (P<0.05), including BMP ligands BMP2, 4, 5, 6, 7, 9, 13 and 14, BMP receptor BMPR1A, and antagonists Chrdl1 and Twsg, whereas the expression levels of some molecules, such as BMP3, BMP12, BMPR1B, BMPR2, Chrd, Chrdl2 and Noggin, were not altered. The phosphorylation levels of Smad1/5/9 was up-regulated in MGH (P<0.05). CONCLUSION: BMP signaling pathway is activated in MGH through the abnormal expression of its components. BMP signaling pathway may be a new target for MGH therapy.     

竹农参与技术创新模式的构建

以解决技术供求矛盾为前提.把政府各级部门、科研机构、竹农、竹加工企业之间存在一种"断层"关系"接续"起来,提出了"接续"方法,即竹农参与技术创新模式的实施和运用.在本文中,提出了竹农参与技术创新模式的基本要求、参与效果的指标、参与模式的基本思路、基本运行机制和主要特色.     

鄱阳湖湿地灰化苔草群落物种多度分布格局沿水分梯度的变化

为揭示鄱阳湖湿地苔草群落的构建机制,选择灰化苔草(Carex cinerascens)群落作为研究对象,通过设立3条样带调查不同水分梯度的群落物种多度,选用断棍模型(BSM)、生态位优先占领模型(NPM)、优势优先模型(DPM)、随机分配模型(RAM)和生态位重叠模型(ONM)5个生态位模型对群落种-多度关系进行拟合,结果表明,1)灰化苔草群落可按土壤水分划分为高湿度、中湿度和低湿度3组,分别对应从湖边、湿地中间和湿地边缘的梯度分布;2)从高到低的水分梯度上,灰化苔草群落的物种数先增加后降低,优势种多度逐渐增加,物种多度分布曲线由相对平缓变为陡峭;3)高湿度灰化苔草群落物种多度分布格局的最佳拟合模型为BSM,中、低湿度的理想模型转变为NPM。研究认为,水分条件的变化是灰化苔草群落物种多度分布格局改变的主因,随着水分梯度降低,群落构建的生态学过程由随机生态位变为生态位优先占领。研究为鄱阳湖湿地多样性保育和生态功能管理提供了理论参考。     

Effect of support on the growth of a woody vine,Wisteria floribunda DC. (Leguminosae)

Seedling ofWisteria floribunda, which belongs to the twiner type of climbing plants, were planted in nursery and the effect of support on the growth of the seedlings was tested. The seedlings were grown with 240 cm-height and 120 cm-height supports (the culms of a dwarf bamboo), and without support. Positive effect of the supports and its length were observed for stem length ofW. floribunda at the end of the growing season. The positive effect of support was also observed for total dry weight. Total dry weight with 240 cm-height support reached more than the double of the seedlings without support. These effects of the support were attributed to die-back behavior of the twining stem, which detached from the support or did not encounter the support. Diameter of the stems without support showed a rapid decrease toward the stem tip, while that with support were relatively constant when they were twining around the support. The existence of the support also affected the dry matter allocation in this species; supported seedlings allocated larger proportion of biomass to current-year stems than unsupported seedlings, although the allocation to the roots was smaller in the supported treatments. Support availability may be critical for the establishment and further growth of the seedlings ofW. floribunda which regenerate at the forest edge and canopy gaps. A part of this report was presented at the 107th Annual Meeting of the Japanese Forestry Society, at Tsukuba, April, 1996.     

格氏栲种群生态学研究Ⅶ.格氏栲种群分布格局的强度与纹理分析

前人都是采用样方方法对格氏栲种群数量的空间格局进行测定,而格局分布有可能受样方大小的影响,且分析过程中没有涉及聚块间密度差的问题,因而无法掌握种群的聚块大小差别及聚块内个体间的离散程度．本研究采用无样方距离法,测定不同生境的格氏栲种群空间格局,分析格氏栲种群格局的强度和纹理．强度以聚块和间隙的密度差来定义,纹理则是体现聚块内个体间的离散程度与诸聚块间的分离程度．测定结果表明,格氏栲种群格局强度从高到低排列次序为：木姜子＞蚊母树＞冬青＞茜草树＞格氏栲＞米槠＞虎皮楠＞木荷;格局纹理从粗到细的顺序是：木荷＝木姜子＞茜草树＞格氏栲＝冬青＞米槠＞蚊母树＞虎皮楠．这一测定结果与作者采用聚集度指标测定相同样地格氏栲种群空间格局的结果基本相符．因此,格氏栲空间格局类型及分布与格氏栲生物学特性及生境的关系密切