湖北省杉木人工林立地类型划分及评价     

李斌成  杜超群  袁慧  吴楚  许业洲 《湖北林业科技》2020,49(2):1-5

以湖北省杉木人工林为研究对象,选择166块具有代表性的杉木人工林标准地,并测定样地的常规立地因子。利用数量化理论Ⅰ的方法建立了杉木优势高与立地因子之间的关系模型,对研究区杉木人工林进行立地类型划分及立地质量评价。结果表明,所选择的5个立地因子与优势高数量化拟合的复相关系数为0.639;海拔、腐殖层厚度和坡位这3个立地因子对优势高的贡献率达84.99%,且影响均达到极显著水平;采用海拔、腐殖层厚度和坡位3个因子构建研究区杉木人工林立地类型,共划分为22类;按照优、良、中、差4个评价等级对166块样地所属的立地类型进行立地质量评价,得出湖北省杉木人工林在中海拔、土壤湿润、土壤养分含量较高的立地条件下生产力较高,研究区立地质量整体处于中等偏上水平的结论。  相似文献   

Effects of elevated CO2 concentration on bulbil germination and early seedling growth in Chinese yam under different air temperatures     

Nguyen Cong Thinh  Etsushi Kumagai  Hiroyuki Shimono 《Plant Production Science》2017,20(3):313-322

The present study investigated the effects of elevated carbon dioxide concentration ([CO₂]) and air temperature on the germination of seed bulbils and the seedling vigour of two Chinese yam lines. Plants were grown under two [CO₂] levels, ambient and elevated (ambient + 200 μmol mol^?1), and two mean air temperature regimes, 22.2 °C (ambient + 1.4 °C) and 25.6 °C (ambient + 5.2 °C). Elevated [CO₂] did not affect bulbil germination under both air temperature regimes. During the early growth stage, the dry weight (DW) of leaves, vines, shoots, roots, belowground parts (roots + tubers) and whole plants were higher under elevated [CO₂] than ambient [CO₂] for both lines under the low- and high-temperature regimes. The values of vigour indexes (index I = germination % × seedling length and index II = germination % × seedling DW) were also higher under elevated [CO₂] than ambient [CO₂] for both lines. These results indicated that Chinese yam seedlings respond positively to elevated [CO₂] during the early growth stage. The above:belowground DW ratios were lower under elevated [CO₂] than ambient [CO₂] in seedlings with very small new tubers for both yam lines, indicating that elevated [CO₂] strongly affected the root growth in the early growth stage. The DWs of post-treatment seed bulbils were higher in the elevated [CO₂] under both air temperature regimes. The results showed that Chinese yam used a smaller amount of the reserves in seed bulbils under elevated [CO₂] than under ambient [CO₂].  相似文献   

氮素营养调控植物逆境适应的机理研究     

钟楚  简少芬 《华北农学报》2020,35(z1):424-432

  相似文献   

角形区域的Teichmuler极值映照     

程金发  诸玉明  顾广泽 《湖南农业大学学报(自然科学版)》1996,23(5)

采用二次微分的方法，得到了角形区域Ω１的Ａｆｆｉｎｅ变换关于其边界值不是极值映照．并明确给出在边界同伦下唯一极值的Ｔｅｉｃｈｍｕｌｅｒ映照．  相似文献   

新城疫（ND）—减蛋综合征（EDS76）蜂胶二联灭活疫苗的研制Ⅰ．制苗工艺、疫苗安全性和免疫原性试验   总被引：6，自引：0，他引：6  

沈志强  林初文  刘吉山  张兴晓  徐可利  柴家前 《中国兽医学报》2001,21(1):25-27

将新城疫病毒（NDV）Colon-30株和减蛋综合征病毒（EDS76AV）－127株分别接种于非免疫鸡胚和鸭胚，制备抗原液。抗原液经甲醛灭活后，与纯化的天然免疫增强剂蜂胶乳化，制成鸡新城疫（ND）－减蛋综合征（EDS76）蜂胶二联灭活疫苗，对疫苗的安全性和免疫原性进行了测定。对3－6周龄易感雏鸡以2倍使用剂量肌内注射，安全性良好；对1日龄雏鸡接种1个使用剂量进行急性毒性试验。15d生长曲线表明，对雏难 影响。对6周龄雏鸡注射1个使用剂量，每批疫苗免疫10只鸡，免疫后5－32d，鸡血清中EDS76血凝抑制（HI）抗体的几何平均滴度（GMT）为6．5－11．8log2,ND血凝抑制（HI）抗体的几何平均滴度（GMT）为4．8－9．8log2；对ND免疫攻毒试验表明，3批疫苗，每羽份含有的半数保护量（PD50）分别为≥127、≥131和≥127。  相似文献   

帽儿山地区21年生长白落叶松种源试验   总被引：3，自引：1，他引：2  

李景云  于秉君  褚延广  王会仁  刘桂丰 《东北林业大学学报》2002,30(4):114-117

对在黑龙江省的东北林业大学帽儿山实验林场21年生长白落叶松种源试验林进行方差分析。结果表明，种源间差异显著；生长性状，抗性与各种源间的经度，纬度，海拔高度及气候因子相关分析结果表明，海拔垂直梯度渐变为主，纬向渐变为辅的连续变异是长白落叶松生长性状的基本变异模式，降水量和日照时数是影响长白落叶松生长的主要气候因子，用长白落叶松各种源的相关性状作聚类分析并参照地理气象因子在，遗传距离0.370的水平上将长白落叶松分布范围区10个参试种源划为6个种源区：Ⅰ小北湖种源区。Ⅱ白刀山种源区，Ⅲ完达山种源区，Ⅳ白河种源区，Ⅴ大石头种源区，Ⅵ桓仁种源区；用Duncan法对种源间进行多重比较，并用综合指数法进行选择，表明小北湖种源是长白落叶松优良基因资源中心，是该试验点最佳种源，大海林种源也是可选择种源；从长白落叶松的低等效纬度地区向高等效纬度地区调种，可望获得较大的遗传增益。  相似文献   

Laser manipulation of atoms and particles     

Chu S 《Science (New York, N.Y.)》1991,253(5022):861-866

A variety of powerful techniques to control the position and velocity of neutral particles has been developed. As examples of this new ability, lasers have been used to construct a variety of traps, to cool atoms to temperatures below 3 x 10(-6) kelvin, and to create atomic fountains that may give us a hundredfold increase in the accuracy of atomic clocks. Bacteria can be held with laser traps while they are being viewed in an optical microscope, and organelles within a cell can be manipulated without puncturing the cell wall. Single molecules of DNA can now be stretched out and pinned down in a water solution with optical traps. These new capabilities may soon be applied to a wide variety of scientific questions as diverse as precision measurements of fundamental symmetries in physics and the study of biochemistry on a single molecule basis.  相似文献   

粟品种对粟瘟病的抗病性初步观察     

朱羣 《植物保护学报》1964,3(4):413-413

近年来,粟瘟病在山西省中部及东南部严重发生危害,輕者减产,重者籽粒不收。作者于1962—1963年进行了粟品种間抗病性的初步观察,簡报如下: 在本所試驗地和山西省晋东南区各县良种繁殖場谷子品种区域試驗地共調查品种520个。調查时期:重点品种分苗期、拔节期、拔节末期、抽穗盛期、乳熟期进行;一般品种只在发病盛期(即抽穗盛期)进行。在自然条件下未感染粟瘟病的品种,再在溫室中种植,进行人工接种。抗病性鑑定結果如下: (一)尚未发現有免疫品种。 (二)不同品种对栗瘟病的抗病性有显著差异:在发病盛期調查,高度抗病品种61个,占总数12％,发病指数为0.1—10;抗病品种149个,占总数28.7％,发病指数为10.1—20.0;輕度感病品种128个,占总数24.6％;发病指数为20.1—  相似文献   

优质丰产草莓新品种‘石莓3号’     

杨莉  李莉  郝保春  贾云云  李茂昌  褚风杰 《园艺学报》2005,32(3):560-560

 ‘石莓3号’为高产、大果、优质, 中早熟草莓新品种, 1990年以自育优系‘18322’为母本, ‘全明星’为父本杂交育成。该品种植株生长势强, 丰产性好, 果实大, 风味浓郁, 品质优良, 适宜于我国华北、东北地区栽培。  相似文献   

On farm observations to increase genetic gain in breeding schemes for village poultry production – A simulation study     

Thinh Tuan Chu  John W.M. Bastiaansen  Elise Norberg  Peer Berg 《Acta Agriculturae Scandinavica, Section A - Animal Sciences》2018,68(1):1-10

To improve genetic gain of breeding programs for village poultry production, breeding schemes with observations obtained in village production systems using individual (VIO) and group recording (VGO) were examined under different levels of genotype-by-environment-interactions (GxE). GxE was modeled by varying the correlation between traits measured in the breeding station and village environments for bodyweight (r_{g_BW}) and egg production (r_{g_EP}). Relative and absolute genetic gains obtained from VIO and VGO were used for comparison between the schemes. Results showed that village observations significantly improved genetic gains compared to the scheme without birds tested in the village. The improvement was only slightly larger with individual observations than with group observations. Higher r_{g_BW} and r_{g_EP} led to lower relative genetic gain, but a higher absolute gain of VIO and VGO. It is recommended to apply a breeding scheme using group recording of village performance when strong GxE in breeding for village poultry is expected.  相似文献