岷江上游干旱河谷辐射松种子育苗试验研究   总被引：4，自引：6，他引：4  

吴宗兴  余良海  刘千里  黄泉  王俊华  汪明  赵文  黄晓江 《四川林业科技》2003,24(1):47-55

经过连续 3年对辐射松种苗特性及育苗技术的试验研究 ,结果表明 :( 1)辐射松种子在 5℃的低温条件下贮藏 2年其发芽率比对照提高 6 4 5 % ;( 2 )用 0 5 %的高锰酸钾液对种子进行消毒处理其幼苗出苗率提高 39 2 % ;( 3)用湿润河砂层积催芽的种子其苗木平均苗高 2 4 0cm ,平均地径 0 33cm ,比对照苗高多 4 8cm ,地径大 0 12cm ;( 4)酸性土上培育的苗木平均苗高比碱性土上培育的苗木平均苗高多 9 8cm ,平均地径大 0 16cm ;( 5 )营养袋规格 10cm× 15cm ,营养土配方为腐殖含量 5 0 %的平均苗高 2 3 3cm ,平均地径 0 3cm ,达到一级苗标准 ;( 6 ) 2月底 3月初播种的苗木比 4月底 5月初播种的苗木苗高多 9 1cm ,平均地径大0 16cm ,出苗率提高 35 6 %。经过综合试验研究 ,场圃出苗率由 40 %提高到 80 %以上 ,每公顷产一年生合格营养袋苗达 12 0万株。  相似文献   

红锥天然林土壤理化性质及水源涵养功能的研究   总被引：6，自引：0，他引：6  

黄全能  陈东华  代全林  李辉辉 《福建林业科技》2001,28(2):17-19,28

对福建华安红锥天然林土壤理化性质及林下凋落物持水能力的分析表明 :红锥天然林土壤各营养元素含量丰富 ,表土层养分状况优于深土层 ,但土壤偏酸 ,淋溶与富铝化作用强烈。红锥天然林的土壤容重、孔隙度、持水量及林下凋落物的水源涵养功能均比一般杉木人工林优越。  相似文献   

淳化县泥河沟流域果林发展与综合效益遥感动态研究     

褚泓阳  全志杰 《经济林研究》1996,14(4):14-16

利用不同时期遥感信息资源、结合实地调查测绘，编制不同时期果林类型图，经过叠合比较，建立动态分类系统，获得果林类型动态图，以此分析淳化县泥河沟流域１９８６￣１９９５年果林面积的动态变化与综合效益。  相似文献   

泡桐蛛蛾幼虫空间格局的研究     

邓秀明  诸泉民  苏世春  江素年  陈德兰 《福建林业科技》2002,29(2):17-20

应用聚集度指标法、回归分析法、零频率方法对泡桐蛛蛾幼虫的空间格局进行测定。结果表明 ,泡桐蛛蛾幼虫在林间呈聚集分布 ,分布的基本成分为个体群 ,零频率方法分析泡桐蛛蛾幼虫种群类型为“聚集度逆零频率制约型”。根据泡桐蛛蛾的空间格局提出了抽样技术 ,并根据零频率方法研究结果确定了林间调查的理论抽样数和简单序贯抽样分析表  相似文献   

江西短周期工业原料林造林区划与树种筛选   总被引：1，自引：0，他引：1  

王宗海  吕聚煜  陈述亮  汪德娥  汪泉 《江西林业科技》2005,(5):23-26,37

从植物地理学的视角针对江西各地不同区位、不同水热和地理条件分别提出短周期工业原料林的发展前景和布局.在科学区划的基础上,本着适地适树的原则,着重总结经多年试验筛选出的适宜作短周期工业原料林的造林树种10余个,就选用条件、生物学特性、经济价值及其栽培技术分别进行论述.  相似文献   

纤维性质对成纸性能的影响   总被引：13，自引：0，他引：13  

全金英 《林产工业》1997,(6)

对纤维的三个基本性质－长度、强度和粗度对纸性的影响进行了综述，着重讨论了对强度性质的影响。  相似文献   

石榴溃疡病害病原学研究   总被引：1，自引：0，他引：1  

刘会香  梁军  赵嘉平  王媛  吕全  张星耀 《林业科学》2007,43(4):54-58

对石榴溃疡病害3菌株所引起的病害症状、病原菌的形态学特征、培养学特性、生理学特性及分子遗传多样性等方面进行比较研究.结果表明:石榴疮痂病与石榴果实上增生型症状的病原菌具有更近的亲缘关系,应为同一病原菌引起,推测该病原菌首先侵染石榴侵染枝干,然后侵染石榴的花萼和果实;而石榴干腐病病原菌主要侵染枝干,是否侵染果实及引起症状特征需要继续进行研究和鉴定.  相似文献   

Reproductive Performance and Reconception of Nellore Cows According to Their Pure‐ or Cross‐Bred Calves          下载免费PDF全文

WB Rodrigues  FS Wechsler  E Nogueira 《Reproduction in domestic animals》2015,50(3):431-436

The objective of the present research was to evaluate the effect of a calf's genetic group on the productive and reproductive efficiency of its Nellore dam. Fixed‐time artificial insemination was applied to 800 cows using semen extracted from Nellore, Simmental and Angus Red bulls. Four hundred eleven cows calved, producing 119 Nellore, 103 ½Simmental–½Nellore and 189 ½Nellore–½Angus Red calves. The second mating period, which paired Nellore cows with Simmental bulls, was initiated 10 days after parturitions began and lasted for 5 months. Based on the two successive parturitions, the cumulative parturition rate for calving periods of 3, 4 and 5 months was calculated. Although no significant difference was observed for birth weight among the genetic groups, cross‐bred calves weighed, on average, 10% more than did pure‐bred calves at the age of 205 days. Nellore dams experienced a gestation period that was 7 days longer than did the cross‐bred dams, and the former showed a higher parturition rate at 90 and 120 days of the calving season, but not at 150 days (calving rates of 80.6, 76.4 and 76.2% for mothers of Nellore, ½Nellore–½Angus Red and ½Nellore–½Simmental, respectively, p > 0.05). At 90 and 120 days, Nellore dams produced more kg of calf per mated dam. In conclusion, in a short breeding season, Nellore dams nursing pure‐bred Nellore calves were found to have a higher biological efficiency compared with Nellore dams nursing cross‐bred calves.  相似文献   

Genetic characterization of bovine viral diarrhea virus strains in Beijing,China and innate immune responses of peripheral blood mononuclear cells in persistently infected dairy cattle     

Xiao Gang Weng  Quan Jiang Song  Qiong Wu  Ming Chao Liu  Meng Ling Wang  Jiu Feng Wang 《Journal of veterinary science (Suw?n-si, Korea)》2015,16(4):491-500

To acquire epidemiological data on the bovine viral diarrhea virus (BVDV) and identify cattle persistently infected (PI) with this virus, 4,327 samples from Holstein dairy cows were screened over a four-year period in Beijing, China. Eighteen BVD viruses were isolated, 12 from PI cattle. Based on genetic analysis of their 5''-untranslated region (5''-UTR), the 18 isolates were assigned to subgenotype BVDV-1m, 1a, 1d, 1q, and 1b. To investigate the innate immune responses in the peripheral-blood mononuclear cells of PI cattle, the expression of Toll-like receptors (TLRs), RIG-I-like receptors, interferon-α (IFN-α), IFN-β, myxovirus (influenza virus) resistance 1 (MX1), and interferon stimulatory gene 15 (ISG15) was assessed by qPCR. When compared with healthy cattle, the expression of TLR-7, IFN-α, and IFN-β mRNA was downregulated, but the expression of MX1 and ISG-15 mRNA was upregulated in PI cattle. Immunoblotting analysis revealed that the expression of interferon regulatory factor 3 (IRF-3) and IRF-7 was lower in PI cattle than in healthy cattle. Thus, BVDV-1m and 1a are the predominant subgenotypes in the Beijing region, and the strains are highly divergent. Our findings also suggest that the TLR-7/IRF-7 signaling pathway plays a role in evasion of host restriction by BVDV.  相似文献   

可再生能源大数据在智慧城市规划设计中产生的影响分析     

李达耀  黄焕晟  胡荃  韦小惠  金成国 《绿色科技》2021,(2)

指出了近几年云计算等字眼开始频繁地出现在我们的视野中,大数据及其相关技术的逐渐普及开始强烈冲击各个传统行业。就规划行业而言,空前丰富的城市数据得以全面搜集,规划师们头一次获得了以个体为设计出发点的数据条件。可再生能源大数据记录着城市可再生能源的应用及其效果,对实现城市能源的可持续发展起着至关重要的作用。对可再生能源大数据会在未来的城市规划设计过程中产生何种影响进行了分析和探讨,为当前对城乡规划未来发展的探索提供参考。  相似文献