石棉县牧草种子生产试验

对9个禾本科牧草品种，经过一年的田间试验，结果表明：多花黑麦草品种中，种子产量最高的是按60％理论播量的赣选一号，高速116．7kg/666．7m2；多年生黑麦草品种中，种子产量最高的是按80%理论播量的Mendat，产量为53．9kg/666．7m2；其余7个品种也适应石棉县气候环境。由此可见，牧草种子生产可在石棉县推广。     

春施多效唑对高羊茅生长及饲草品质影响

春施不同浓度的多效唑对高羊茅Festuca arundinacea的生长及饲草品质影响的研究结果表明,多效唑对高羊茅的营养生长具有显著的抑制作用,多效唑处理后30 d,处理浓度为250,500,750和1 000 mg/L时,株高分别比对照降低了37.9%,43.5%,62.6%和71.1%.多效唑处理后叶色加深,叶片变小,叶面积指数下降,光合有效面积减小,地上部干物质积累量减少,与此同时单株茎蘖数增加,叶茎比提高,饲草中粗蛋白含量增加,中性洗涤纤维含量下降,饲草品质得到了改善.     

高羊茅单株耐热性相关分子标记的筛选及其与越夏性的关系研究

筛选与高羊茅单株耐热性和越夏性相关的分子标记有利于建立高效育种体系。以来自于耐热性不同的12个高羊茅种质资源的216个单株为耐热性分子标记筛选的基础群体,在人工高温(40℃/35℃,昼/夜各12 h)和夏季田间自然条件下分别进行了耐热性和越夏性鉴定。运用简单重复序列区间(inter-simple sequence repeat,ISSR)和随机扩增多态性DNA(random amplified polymorphism DNA,RAPD)分子标记技术,采用改良的集团分离分析法(modified bulked segregant analysis,BSA),从800个RAPD和100个ISSR分子标记中筛选与耐热性相关分子标记,并研究其与单株越夏性的关系。结果表明,单株的耐热性与越夏性的相关程度较低(决定系数为3.4%);引物351扩增的750 bp条带(351-T750)与耐热性显著相关,而引物138扩增的950 bp条带(138-T950)则与耐热性和越夏性均显著相关。可以推论,耐热性强和/或越夏性强单株材料需要分别在人工高温和夏季田间自然条件下加以鉴定筛选;351-T750可应用于耐热性强单株的辅助选择,而138-T950则可以用于耐热性强与越夏性强单株的辅助选择。     

高羊茅在中国寒冷潮湿带引种适应性的研究

观察研究了 2 6个高羊茅品种在沈阳地区的生长性能、生物学特性、草坪形成特点及抗性反应 ,并分别对其草坪密度、质地、抗热性、抗病性、绿度、绿期、综合表现进行打分评定 ,结果表明 ,2 6个参试品种均适应沈阳地区的土壤气候 ,因其抗性强 ,管理粗放 ,是北方地区有推广价值的草坪草种之一     

包膜控释尿素对高羊茅草坪建植期生长的影响

应用盆栽试验研究了释放期为30 d(U30)和80 d(U80)的控释包膜尿素一次性基施对高羊茅Festuca arundinacea草坪建植期生长情况的影响。结果表明：在施氮量相等的情况下,单一施用U80处理草坪成坪时间最短,仅为51 d,播种85 d后,其叶绿素仪读值（SPAD）高于其他处理。出苗后各处理地上生物量呈现先升高后降低的单峰变化趋势。单一施用U80处理草坪成坪后,生长速度较其他处理更为平缓。此外,单一施用U80处理和U80配施30％普通尿素处理,草坪地下生物量积累总量明显高于单一施用普通尿素处理。     

Characteristics of Interference Effects on Local Pressure of Two Square Tall Buildings in Tandem Arrangement

Wind tunnel tests were carried out to study the wind pressure on principal square building adjacent to another one in tandem. The interference effects on local pressure of the principal building were analyzed with different positions and heights of interfering building. It is shown that as height ratio is fixed, mean pressures on windward face are suctions when spacing ratio is less than 3, otherwise they are positive. The magnitudes of mean suctions on the side and leeward faces and fluctuating pressures on each face all get their maximums when spacing ratio is 3. As height ratios change, the magnitudes of mean suction on windward face increase with height ratio, meanwhile, the magnitudes on other faces obtain their minimums as the height ratio is 1.0 and the spacing ratio is less than 3. The fluctuating pressures on the windward and side faces get their maximums and that on the leeward face reaches its minimum as the height ratio is 1.0. When the spacing ratio is greater than 3, mean pressures on each face decrease, while fluctuating pressures on the windward and side faces increase as the height ratio increases, and the fluctuating pressures on the leeward face get the minimum when the height ratio is 1.0.     

Exploration and Collection of Coconut Germplasm in Kadmat and Amini Islands of Lakshadweep, India

Coconut, Cocos nucifera L. is an important plantation crop of the tropics. Lakshadweep group of islands in the Arabian Sea are considered to be home to some important coconut cultivars. The present exploration was planned to sample the variability within the population of Laccadive ordinary tall (LCT), Laccadive micro tall (LMT) from two islands, Amini and Kadmat, of Lakshadweep. Sampling was done from 24 sites in Amini and 13 sites in Kadmat. On an average 10 palms were sampled from each site. During the trip, five accessions of LCT, three of LMT and one of Kaithathali were collected. Eight fruit component measurements were recorded to study the variability in the population. Intra-population variability was observed in both LCT and LMT. Three forms of LCT belonging to niu kafa, niu vai and introgressed types could be identified. Elongated angular fruits (elliptical) with 70% husk were niu kafa types, round or oval shaped ones with 55% husk were niu vai types and pear shaped ones with 58% husk were the introgressed forms. This exploration trip unearthed the missing link of niu vai type in the form of round fruit type which has not been reported earlier. Identification of different groups in LCT has far reaching implications in breeding. In the production of hybrids involving LCT, selection of mother palms of LCT is crucial. It is suggested that the elliptical fruit types may be avoided in the production of commercial hybrids, since it has high percentage of husk.     

哈尔滨市大树移植实践与思考

论述了哈尔滨市“大树进城”的移植实践过程 ;阐明城市从栽植小树苗 ,缓慢地发挥生态效益到移植大树加快生态效益 ,是尽快改善城市生态环境的最有效途径     

高枝修剪机剪枝运动学和动力学分析

高枝修剪机在修剪过程中锯切力大小不断变化,圆锯片、齿轮副及操作杆承受的作用力和力矩也随之变化,这些因素都会影响修剪杌工作的稳定性.通过对高枝修剪机在工作过程中的运动学和动力学分析,建立相关修枝动力学模型,确定影响锯切平衡的主要因素,为高枝修剪机的结构优化设计提供理论依据.     

深圳市鹏茜大理岩矿采空区稳定性数值模拟研究

由于采空区对原有岩体应力平衡的破坏,可能导致地面塌陷等地质灾害,威胁地表建筑、工程的安全.为研究深圳鹏茜大理岩矿采空区的稳定性,采用Flac3D建立三维数值模型对采空区围岩的应力、位移和塑性区进行了分析;同时,针对鹏茜大理岩矿不同倾角岩层段上、下水平矿柱的稳定性进行了计算.综合研究结果表明:鹏茜大理岩矿采空区整体稳定性...