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当归[Angelica sinensis(Oliv.)Diels]种苗的大小直接影响着当归的产量,过大的种苗大田移栽后早期抽薹率很高,过小的种苗移栽成活率很低,而当归日光温室反季节育苗在不同时期所育种苗大小相差较大。为了提高当归产量、降低当归早期抽薹率,对"岷归2号"进行了日光温室反季节育苗不同播期的试验研究,结果表明:育苗播种期10月为当归日光温室反季节育苗最佳时期,所育种苗综合性状较优,大田移栽后成活率较高、抽薹率较低、产量较高。因此,日光温室反季节育苗最佳播种时期为10月,可提高当归产量、降低当归早期抽薹率。 相似文献
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为探讨不同栽培区域对皮胎果+当归+大蒜模式3种作物产品品质的影响,我们在不同区域开展了皮胎果+当归+大蒜栽培模式研究,检测了3种作物产品品质。结果表明,皮胎果硒含量随海拔升高而降低,含量大于我国富硒食品含硒量标准;当归酸溶性灰分含量在海拔2 263m以上随海拔升高而降低,水溶性灰分含量随海拔升高而增加;当归在海拔最高(2 351m)种植,当归根阿魏酸含量最高。大蒜头所含热量,在海拔2 315m以下随海拔升高而提高;总灰分含量基本接近。 相似文献
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食用土当归在我国分布较广,资源较丰富,民间早作为蔬菜食用。为寻求新的药物资源,本文用薄层层析法和反相高效液相色谱法对食用土当归化学成分进行了分析,并用薄层层析法-分光光度法测定了齐墩果酸的含量为2.6%。 相似文献
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不少中药来自林木和林区。云南在历史上就是我国著名的中药产区,既产砂仁、儿茶等“南药”,又产当归、秦艽、黄莲、贝母等“北药”。云南中药品种多,质量优良,在国内外声誉很高。云南的高寒地区包括了海拔2,500米以上的地带。这些地带,大多为针阔混交林、针叶林以及灌木草甸带。在造林的同时可套种冷凉中药如云黄莲、云当归、 相似文献
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燕山山地华北落叶松单株生物量与生产力研究 总被引:2,自引:0,他引:2
根据对33株华北落叶松标准木的生物量实测资料,对林木单株与器官生物量分配情况进行了探讨,建立了以胸径、树高为自变量的生物量预测模型;提出了在幼树期(树龄7-15a或胸径1.7-6.6cm)根茎比平均值为0.159,幼树期以后(当树龄超过15a或胸径大于6.6cm时)根冠比平均值为0.236,建立了以林龄、胸径为自变量的根冠比预测模型;以去皮材积一生物量模型为基础进行解析木的生产力模拟,多年平均生产力变化在211.258-4512.804g/a,16a以后进入速生期,到49a时年生产力水平仍很高,建议生产上主伐林龄应推迟到50a以后。 相似文献
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以色木槭、拧劲槭天然林解析木为对象,用Logistic模型对树高、胸径、材积生长进行拟合,研究其生长规律。结果表明:树高、材积生长拟合效果良好。色木槭树高生长9 a前为生长前期,9~31 a为速生期,20 a为生长高峰年,31 a后为生长后期;材积生长25 a前为生长前期,25~38 a为速生期,32 a为生长高峰年,38 a后为生长后期。拧劲槭树高生长9 a前为生长前期,9~40 a为速生期,12 a为生长高峰年,40 a后为生长后期;材积生长28 a前为生长前期,28~43 a为速生期,36 a为生长高峰年,43 a后为生长后期。色木槭、拧劲槭树高、胸径生长在15 a前比较接近,15 a后色木槭明显高于拧劲槭;色木槭、拧劲槭材积生长在18 a前比较接近,18 a后色木槭明显高于拧劲槭。 相似文献
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高分辨率遥感图像均值调整法分割技术研究 总被引:1,自引:1,他引:1
遥感图像分割是将以像元为基础的图像转化为以对象为基础的过程,因此,遥感图像分割是遥感图像高级分析的基础.对于中、低分辨率遥感图像来说,单个像元的面积较大,且混合像元现象严重,图像分割会产生较大的误差.高分辨率遥感图像单个像元的面积较小,分割后图像上单个对象内含若干像元,便于分析和提取信息.以高分辨率遥感图像Q u ickB ird和IKONO S为研究对象,采用均值调整法对图像进行分割和精度检验.结果表明:采用均值调整法进行高分辨率遥感图像分割具有较好的效果,图像分割的速度和精度均较高. 相似文献
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Lu Zhao Yin Wang Han-lin Shen Xu-dong Shen Yan Nie Ying Wang Ting Han Ming Yin Qiao-yan Zhang 《Fitoterapia》2012
Two novel homogeneous polysaccharides, APS-1a and APS-3a were successfully isolated from the root of Angelica sinensis. APS-1a was composed of galactose, arabinose and glucose in a relatively molar percentage of 57.34%, 27.67% and 14.98%, and had a molecular weight of 49.0 kDa, whereas APS-3a was composed of galactose, arabinose and glucose in a relatively molar percentage of 84.54%, 6.50%, and 8.96%, and had a molecular weight of 65.4 kDa. APS-1a and APS-3a mainly consisted of 1,4-linked galactose, 1,3,6-linked galactose, T-galactose and T-arabinose, and the molar ratio of each linkage was different between APS-1a and APS-3a. The bioactivity analysis showed that APS-1a and APS-3a increased the thymus and spleen index, the number of red blood cell (RBC) and white blood cell (WBC) in peripheral blood and the cellularity of bone marrow cell numbers in irradiated mice, protected mice against radiation-induced micronucleus formation in bone marrow, suggesting that polysaccharides could be used as radioprotective agents, especially for promoting bone marrow hematopoiesis. 相似文献
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采用解析木分析方法研究长白落叶松人工林生长过程,结果表明:径级10~15 a生生长较快,20 a生以后趋向稳定;树高15 a生以前生长迅速,20 a生后稳定生长;材积生长从20 a开始到40 a逐年增长,是生长旺盛期,40 a生平均生长量分别较20 a、25 a、30 a生增长了73.5%、41.5%和19.8%。40 a生落叶松每公顷木材产量分别为20 a、25 a生时的220%和169%,产值分别为292%和182%,年产值分别为146%和114%。长白落叶松人工林的培育方向应确定以大径级材为主。 相似文献
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采伐联合机机械手运动学分析及雅可比矩阵求解 总被引:1,自引:1,他引:0
介绍了采伐联合机的基本结构和工作原理,分析其关节式机械手各杆件之间的位置关系,建立了机械手坐标系统及运动学模型,并求出了运动学正解和逆解。在此基础上推导了雅可比矩阵及笛卡尔空间与关节空间的坐标变换关系,为机械手运动控制系统的设计提供了依据。 相似文献
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红松人工林生物量的测定及其分析 总被引:1,自引:0,他引:1
利用平均标准木法测定不同林龄和不同密度红松人工林乔木层生物量及其分布格局。结果表明:15a生红松生物量达到19.19t/hm2,25a达到65.27t/hm2,35a达到135.36t/hm2,平均为73.27t/hm2。在各器官的生物量中,树干生物量最大,约占总生物量的一半左右,并随着林龄的增大,其比值也在增大,平均为54.95%;根占总生物量的比例是相对稳定的,不同林龄阶段均保持在20%左右,平均为22.08%;枝叶占总生物量的比例随林龄的增大而减少,15a时占39.9%,25年时为25.60%,35年时为19.63%。在地上各器官垂直分布中,均以0~2m层生物量最大,从0~2m层(不含0~2m层)向上各层生物量呈缓慢减小趋势,到树梢时又突然减小;枝叶生物量在垂直高度上的分布是两头小中间大的分布,其最大值在15a时出现在第2高度层,25a和30a平均出现在第3高度层。 相似文献
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In the subsistence-agricultural region of eastern Zambia, less than 10% of the households have adequate supply of maize (Zea mays L.), the staple food, throughout the year. A major constraint to increasing crop production in the region is poor fertility
status of the soil. In order to address this problem, improved fallow has been introduced as a technology for improving soil
fertility within a short span of two to three years. Farmers have been testing the technology and a number of empirical studies
have been undertaken over the years to identify the factors influencing farmers' decision to adopt the technology. This paper
presents a synthesis of the results of adoption studies and highlights generic issues on the adoption of improved fallows
in Zambia. The synthesis indicates that farmers' decision on technology adoption does not have a simple directed relationship
of some technological characteristics only, but constitutes a matrix of factors including household characteristics, community
level factors, socioeconomic constraints and incentives that farmers face, access to information, local institutional arrangements
and macro policies on agriculture. The adoption of improved fallows is not strictly speaking a binary choice problem but a
continuous process in which farmers occupy a position along a continuum in the adoption path. Further, adoption of improved
fallows may not take place in a policy vacuum but needs to be facilitated by appropriate and conducive policy and institutional
incentives. Several questions and issues that require further study emerge from the synthesis. These include determination
of the relative importance of the factors in the adoption matrix, identification of the conditions under which farmers use
a combination of inputs and their profitability under changing price scenarios, exact definition to delineate between `non-adopters',
`testers' and `adopters' of agroforestry technologies, and understanding the impact of cash crop farming in farmers' adoption
decisions of improved fallows (where off farm opportunities exist). Further, there is a need to determine the inter-relationship
between household poverty, labor availability and the adoption of improved fallows and, to evaluate a combination of policy
interventions at both national and local level to promote the adoption of agroforestry-based soil fertility management.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
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中国自然保护区类型比较与可持续发展思考 总被引:1,自引:0,他引:1
自20世纪90年代以来,由于各种原因,特别是在经济利益驱动下,在我国出现了同一地域既是自然保护区又是森林公园或风景名胜区的混乱局面,对自然保护事业与公众娱乐事业的和谐发展产生了不利影响。文章从我国现有法律制度出发,对三者进行了比较分析,同时,针对当前我国实践中存在的问题,建议通过制订国家遗产法、建立新型的国家遗产管理体制和监督管理机制,促进我国自然保护事业与公众娱乐事业的和谐、健康与可持续发展。 相似文献
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Zhou Zhiqiang Liu Tong Zhou Lin Faculty of Forest Resources Environment Northeast Forestry University Hexing Road Harbin P. R. China Natural Resources Institute of Heilongjiang Province Haping Road Harbin P. R. China 《中国林学(英文版)》2003,5(3)
1 Introduction The Great Xingan Mountains in the northeast of China is covered by boreal forests. Larch (Larix gmelinii) represents the most frequent tree species. Mongolian pine (Pinus sylvestris var. mongolica) can be found on about 3% of the forested land. Pine forests contain the most valuable timber, which is harvested on large areas and transported to southern regions. Within these forests, few studies exist about the flora, the distribution of the dominating tree species, and their… 相似文献