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1.
苗圃转让     
今年顺义区苗圃绿化、美化苗木达1120多种、1.12亿株。其中油松、白皮松、华山松、雪松、桧柏、侧柏等常绿树13157亩,1650万株,占育苗总面积的23%;连翘、碧桃、榆叶梅、紫叶李、紫蔽、紫荆、月季、玫瑰、黄刺梅、黄杨、女贞等花灌木5468亩,1455万株,占育苗总面积的10%;白腊、元宝枫、栾树、国槐、银杏、合欢、龙爪槐、杜仲、千头椿、金丝柳、各种品种杨等落叶乔木37375亩,8095万株,占育苗总面积的67%。  相似文献   

2.
大丽花块根繁育和栽培技术   总被引:2,自引:0,他引:2  
大丽花(Dahlia pinnata Cav)菊科,大丽花属,多年生草本,原产墨西哥,又名大丽菊、大理花、天竺牡丹、西番莲、地瓜花,具有植株粗壮、花期长、花朵硕大,品种繁多、花色鲜艳、适应性强等特点。是美化公园,布置庭院、花坛、花境以及切花陈设的较好花卉材料。大丽花为世界名花之一,目前世界约有3万多个品种,我国有500余品种。  相似文献   

3.
木棉(Gossampinus malabarica)又名攀枝花、红棉、英雄树、烽火树,属木棉科木棉属落叶高大乔木.木棉广泛分布在我国四川、云南、贵州、广西、广东,生长在江河沿岸、山地阳坡及村边道路旁,喜光、耐高温,对土壤要求不苛刻.在四川攀枝花地区木棉树于1月-2月份开花,先花后叶,花色艳丽,有红色、金黄、淡黄色等颜色,树形高大伟岸,是优良的园林绿化树种.木棉树现是攀枝花市市花和广州市市树,在园林绿化中常作行道树、庭荫树、景园树、盆景树等.木棉经嫁接后2 a-3 a开花,嫁接苗可作盆景矮化栽培,观赏价值高.本文介绍了木棉的嫁接育苗技术.  相似文献   

4.
To improve multi-environmental trial(MET)analysis,a compound method—which combines factor analytic(FA)model with additive main effect and multiplicative interaction(AMMI)and genotype main effect plus genotype-by-environment interaction(GGE)biplot—was conducted in this study.The diameter at breast height of 36 open-pollinated(OP)families of Pinus taeda at six sites in South China was used as a raw dataset.The best linear unbiased prediction(BLUP)data of all individual trees in each site was obtained by fitting the spatial effects with the FA method from raw data.The raw data and BLUP data were analyzed and compared by using the AMMI and GGE biplot.BLUP results showed that the six sites were heterogeneous and spatial variation could be effectively fitted by spatial analysis with the FA method.AMMI analysis identified that two datasets had highly significant effects on the site,family,and their interactions,while BLUP data had a smaller residual error,but higher variation explaining ability and more credible stability than raw data.GGE biplot results revealed that raw data and BLUP data had different results in mega-environment delineation,test-environment evaluation,and genotype evaluation.In addition,BLUP data results were more reasonable due to the stronger analytical ability of the first two principal components.Our study suggests that the compound method combing the FA method with the AMMI and GGE biplot could improve the analysis result of MET data in Pinus teada as it was more reliable than direct AMMI and GGE biplot analysis on raw data.  相似文献   

5.
Natural spruce-fir mixed stand is one of the main forest types in the world,and also has huge ecological,economic and social benefits.According to the structural characteristics and succession laws of natural spruce-fir forest,it is urgent and significant to develop scientific management measures for natural spruce-fir mixed stand in line with local conditions.The article outlined the characteristics of the distribution and structure, regeneration and succession laws of natural spruce-fir forest,and analyzed the current situation and existing problems of natural spruce-fir forest management.The following recommendations were eventually made:1) In no cutting area,all logging activities should be banned.In a restricted cutting area,the cutting intensity should be generally controlled within 15%of the stock volume before cutting.On the commodity forest management area, the appropriate cutting intensity should be determined according to the volume per hectare,determine and classification management should be implemented in accordance with the characteristics of forest,to ensure the scientific selective cutting.2) Closure for afforestation,planting and repair planting should be adopted on vegetation-intensive land,sparse shrubs covered land and harvesting slash,in order to accelerate natural regeneration.3) The in situ conservation should be conducted in nature reserves and scientific experiment stations of rare and endangered species,such as Abies chensiensis,Picea neoveitchii,Abies vuanbaoshanensis,to reduce human destruction.4) It is supposed to collect seeds in time,establish nursery,actively establish forest, expand artificial population and promote natural regeneration.  相似文献   

6.
蚊子、苍蝇、螳螂、臭虫、蜘蛛、蚂蚁之类害虫,在家庭、工厂、办公室、医院、学校、酒店等地,随处可见,无处不入.这些昆虫不但给人们的生活带来很多烦恼,更重要的是,他们导致疾病传播,从而严重危害人们的身体健康.所以,根除害虫,改变居住环境,早已成为人们关注的问题.  相似文献   

7.
肥胖是一种常见的慢性疾病,它是由于生理化机能的改变而引起的体内脂肪沉积量过多,造成体重增加,导致机体发生一系列病理、生理变化的病症.肥胖症是一种全身性代谢疾病,除引起身体外形的改变外,过多的脂肪可带来物理性的负荷,还是各种疾病的"培养箱".肥胖人群平均寿命明显低于正常体重的人群,同时肥胖症还是心血管疾病、糖尿病、脂肪肝、肿瘤的温床,它是一种营养代谢性疾病.减肥首先必须从能量的摄入入手,减少热能的吸收.  相似文献   

8.
当前现代化的航天、航空、汽车、机械、电子、民用建筑、化工等行业迫切要求具备很高的力学性能及耐热、耐磨、耐化学性能的材料.因此高分子材料发展的一个重要方向就是通过对现有聚合物进行物理和化学改性,使其进一步高性能化、结构化、工程化.北京化工大学研制的聚氯乙烯合金是通过挤出机的力学、化学作用及接枝、复合技术使聚氯乙烯塑料工程化,成为物理性能可与ABS相比拟的新材料.聚氯乙烯合金具有高流动性、高韧性,完全可以代替ABS注塑计算机、电视机、冰箱、照相机、仪表等外壳.聚氯乙烯合金还具有良好的耐寒性,可制作各种规格的异型材,包括门窗、上水管道等.产品市场前景好,具有很强的竞争力,有很好的经济效益和社会效益.  相似文献   

9.
浙江省重点公益林松类生物量模型研究   总被引:2,自引:0,他引:2  
根据浙江省森林群落和树种分布特点,在浙江省200万hm^2重点公益林范围内,按气候区、林分类型、林龄组成、立地条件、林分组成等设置松类树种(包括马尾松、黄山松、湿地松、华南松和火炬松)典型样地122个,实测标准木255株。通过相关分析表明,树干干重、木材干重、皮干重、枝干重、冠干重、根干重与胸径和树高的相关系数较大,其冠干重、枝干重、叶干重则与胸径和树高以及枝下高有较大的相关系数,从变量得到的简洁性和准确性考虑,经不同模型的拟合和检验,确定了松类生物量各器官的独立模型,总量、木材、树皮、树根、树干的模型结构为W=c1D^c2H^c3,树叶、树枝、树冠的模型结构为W=c1D^c2L^c3;拟合了浙江省重点公益林松类生物量各器官及总量的独立模型和相容性模型,经检验,各模型均具有较好的拟合精度和预估水平,样本总体预估精度指旨标(P%)在多数分量中以相容性模型最高,而且相对误差绝对值指标(E2%)最小,总量、木材,树干、树皮的预估精度超过了独立模型,其他分量仍保持了独立模型的水平;而且相对误差绝对值均略高于或等于独立模型。  相似文献   

10.
This paper proposes an automatic method of pore combination recognition,which is an important feature to hardwood recognition.After extracting edge from wood microscopic cross-section, based on area histogram of the similar circle regions,the method classifies all regions into two classes with maximum between-class variance,so as to distinguish the pore from other textures,which are similar in shapes but different in sizes.Meanwhile, second objective function about average area of closed regions is used to improve the pore segmentation performance.At last,the method uses adjacency degree of pore set to judge pore combination.The experiments demonstrate that the task of pore segmentation can be completed successfully for all kinds of pore distribution and combination,and also the correct combinations of pores are given.  相似文献   

11.
桤木人工林细根与土壤养分含量季节动态变化   总被引:2,自引:2,他引:0  
对桤木人工林细根、土壤养分含量的季节变化及其两者之间的关系进行了研究.结果表明:(1)桤木细根中大量元素N、Ca、K、Mg、P含量冬季高,春季最低;微量元素Fe、Mn、Zn、Cu、Pb、Ni、Cd含量冬季最低,春夏季较高.(2)土壤各层中大量元素N、Ca、K、Mg、P含量冬季最低,夏季最高;微量元素Mn、Zn含量在冬季最低,秋季最高;Fe、Ni、Pb、Cu、Cd含量在冬季最高,春秋较低.(3)细根和土壤中大量元素含量在冬季存在负相关关系,微量元素Fe、Ni、Cd含量在一年四季均存在显著负相关关系,Mn、Cu含量在春季、夏季和秋季存在负相关关系,Zn、Pb含量在春季、夏季和秋季存在正相关关系.  相似文献   

12.
白蜡虫在寄主植物上的分布特征研究   总被引:5,自引:3,他引:5       下载免费PDF全文
白蜡虫在寄主上的分布与方向和寄主枝条的位置有关,不同虫基分布特征不同,在定叶期,白蜡早咎群方位上差异不太大,但雌雄虫在方位分布上有明显差异。种群数量分布依次为东(28.05%),南(26.55%),西(25.06%),北(20.34%),雌虫依次为东(32.16%),南927.36%),北(20.34%),西(18.65%);雄虫依次为西(30.76%),南(25.84%),东(24.29%),北  相似文献   

13.
Carbon (C), nitrogen (N), and phosphorous (P) levels and their stoichiometry in plant components (leaves, branch trunks, roots) of trees in a karst forest and non-karst forest are compared. The results show that the C contents, C:N and C:P ratios of dominant species in the karst forest were lower than those in the non-karst forest, but the N and P and the N:P ratio were higher;C:N:P ratios in plant organs of trees in the karst forest were in the order of trunks>roots>branches>leaves. However, C:N:P ratio in the non-karst forest trees were trunks>branches>roots>leaves. Moreover, ratio of C:N:P in trunks was highest and lowest in leaves in both forests. In non-karst forest trees, N:P was in the order of leaves> roots>branches>trunks. There were no significant differences in the ratio of N:P in different plant components of trees in the karst forest. However, in karst and non-karst forest trees, the ratio of N:P in leaves was highest;positive correlations between N and P contents, and N and N:P ratios were observed in both karst and non-karst forests (p<0.001). Negative correlations between P and N:P ratios (p<0.05) were observed in karst forest trees, while positive correlations were observed in non-karst forest trees.  相似文献   

14.
对落叶松人工纯林不同发育阶段幼龄林、中龄林、近熟林、成熟林及二代幼龄林土壤腐殖物质组分变化及其对酸度的影响进行研究,以次生林和一代幼龄林为对照,比较不同发育阶段落叶松人工林与天然次生林、一代幼龄林与二代幼龄林土壤有机质含量、腐殖物质组分特征的差异.结果表明:落叶松人工林从幼龄林到近熟林根际与非根际土壤有机质含量、胡敏酸含碳量、胡敏素含碳量随林龄的增大而增大;近熟林到成熟林根际与非根际土壤有机质含量、富啡酸含碳量和胡敏素含碳量随着林龄的增大而降低;土壤腐殖化程度(土壤中胡敏酸占全C的百分比)和土壤腐殖质中胡敏酸含碳量与富啡酸含碳量比值(HA/FA)为次生林大于幼龄林和近熟林;二代幼龄林与一代幼龄林相比,根际土壤有机质含量、富啡酸含碳量和胡敏素含碳量分别降低4.53%、35.8%和1.98%,非根际土壤有机质含量、胡敏酸含碳量、富啡酸含碳量和胡敏素含碳量分别提高46.44%、43.69%、47.45%和49.5%;土壤腐殖物质组分与酸度的相关关系随着年龄的变化而变化,并且不同发育阶段根际土壤腐殖物质组分与根际土壤活性酸(pH值)、交换性酸、水解性酸相关性密切.  相似文献   

15.
Abstract

Seasonal behavior of vascular cambium and development of secondary xylem were studied in the 2-3-years-old branches of Azadirachta indica A. Juss. (Meliaceae) growing in moist deciduous (MDF), dry deciduous (DDF) and scrub land (SF) forests of Gujarat State. Development of xylem began with the sprouting of new leaves in January in both MDF and DDF. Xylem production culminated in July in MDF whereas it reached peak in April and July in DDF. Cambial cells ceased to divide with the maturation of leaves in November and October in MDF and DDF, respectively. Mature xylem and phloem derivatives surrounded the cambium in December in MDF and November in DDF. Radial growth in the branches of trees growing in SF was found continuous throughout the year with peak cambial activity in April, July and November. In all the three forests, maximal radial growth was encountered in July when the rains were heavy. Cambial activity and xylem development showed significant correlation with the phenology of the trees in MDF and DDF whereas cambium was found active throughout the year and no correlation was found between the cambial activity and phenology in SF.  相似文献   

16.
在小兴安岭阔叶红松(Pinus koraiensis)混交林林隙及其周围郁闭林分内,通过网格法布点,于2010年7—9月使用TDR200测定中、小林隙I III层的土壤含水量。运用经典统计学和地统计学方法分析各土层土壤含水量的基本特征及同一林隙各样点土壤含水量的差异性,利用surfer 8.0软件进行克立格空间局部插值,并绘制各土层土壤含水量空间分布图,分析林隙土壤含水量的时空异质性。结果表明:中、小林隙I III土层土壤含水量均呈中等程度变异。随着土层深度的增加,土壤含水量提高,土壤含水量的斑块连接度增大。土壤含水量最大值出现在林隙中心和近中心区域,并呈现出随土层深度增加面积扩大并向中心靠拢的变化趋势;土壤含水量最小值出现在扩展林隙及其郁闭林分内。中、小林隙中心与边缘土壤含水量的差异均为II层较I和III层大。7—9月土壤含水量均值呈单峰型变化,最大值出现在8月,且中林隙土壤含水量较小林隙的大;9月I和II层土壤含水量较8月大幅度减小,但III层与8月相比差异较小。  相似文献   

17.
树叶中重金属含量及其指示大气污染的研究   总被引:4,自引:0,他引:4  
通过对南京市区交通流量大的区域和相时清洁区(江苏省林科院)不同植物叶片重金属元素(Pb、Cd、Cu)含量的分析,研究了大气污染指数,初步探讨了植物重金属含量与城市大气污染之间的关系.研究表明.植物叶片中重金属Pb、Cd和Cu的累积量与大气中Pb、Cd和Cu的相对含量呈显著正相关;所调查绿化树种叶片的重金属含量因重金属种类、采样区和树种的不同具有明显差异,悬铃木叶片累积Pb的能力最强,而杨树叶片对Cd和Cu的累积能力最强.市区大气重金属质量状况为:交通枢纽区中央门、南京化工厂和沪宁高速属于重污染,生活区新庄属于中轻度污染,远郊林科院属于无污染区.  相似文献   

18.
In fall (November 2005) and winter (February 2006), we collected current-year foliage of native red spruce (Picea rubens Sarg.) growing in a reference watershed and in a watershed treated in 1999 with wollastonite (CaSiO(3), a slow-release calcium source) to simulate preindustrial soil calcium concentrations (Ca-addition watershed) at the Hubbard Brook Experimental Forest (Thornton, NH). We analyzed nutrition, soluble sugar concentrations, ascorbate peroxidase (APX) activity and cold tolerance, to evaluate the basis of recent (2003) differences between watersheds in red spruce foliar winter injury. Foliar Ca and total sugar concentrations were significantly higher in trees in the Ca-addition watershed than in trees in the reference watershed during both fall (P=0.037 and 0.035, respectively) and winter (P=0.055 and 0.036, respectively). The Ca-addition treatment significantly increased foliar fructose and glucose concentrations in November (P=0.013 and 0.007, respectively) and foliar sucrose concentrations in winter (P=0.040). Foliar APX activity was similar in trees in both watersheds during fall (P=0.28), but higher in trees in the Ca-addition watershed during winter (P=0.063). Cold tolerance of foliage was significantly greater in trees in the Ca-addition watershed than in trees in the reference watershed (P<0.001). Our results suggest that low foliar sugar concentrations and APX activity, and reduced cold tolerance in trees in the reference watershed contributed to their high vulnerability to winter injury in 2003. Because the reference watershed reflects forest conditions in the region, the consequences of impaired physiological function caused by soil Ca depletion may have widespread implications for forest health.  相似文献   

19.
Rodent and avian consumption of Holm Oak, Quercus ilex, acorns were examined in central Spain during two high-production seasons, 1990–1991 and 1993–1994, in 1 and 3 large stands and in 6 and 10 small stands (0.2–12 ha) respectively, to study the effects of vertebrate predation on seedling recruitment. Previous data indicate that wood mouse abundance is much higher in small stands. Tree size, frequency of acorn-bearing oaks and acorn abundance were similar in the two sizes of forest stands. Overall acorn consumption was 33.7 times higher in the small stands compared to that in the large stands in 1991, and 3.1 times larger in 1994. Consumption of acorns by mice in the small stands was 49 and 95 times greater than that by birds in the first and second year, respectively. Seedling recruitment was significantly higher in the large stands in both study seasons. Regeneration by ramets was roughly similar in small and large stands in both seasons. Thus, predation by mice was apparently responsible for the failure of sexual reproduction in the small stands. The results suggest that vegetative regeneration might be the prevalent reproductive method of Holm Oaks in small forest tracts.  相似文献   

20.
模拟三峡库区消落带土壤淹水变化特征,设置常规生长水分条件(CK)、轻度干旱水分胁迫(T1)、土壤水饱和(T2)以及水淹(T3)4个处理组,研究池杉当年实生幼苗根系的苹果酸、莽草酸含量以及生物量变化(均以干质量计).结果表明:T1、T2和T3这3组池杉幼苗主根的苹果酸、莽草酸含量以及生物量均未与CK组达到显著性差异;T2和T3组侧根苹果酸平均含量分别显著高出CK组1.7和2.2倍,总根苹果酸平均含量显著高于CK组0.8和1.5倍;T1组的侧根、总根苹果酸平均含量与CK组均未达到显著差异;与侧根苹果酸的变化类似,T2和T3组侧根莽草酸平均含量分别高出CK组0.4和1.1倍,这与Tl组低于CK组0.5倍形成鲜明对比;T2和T3组总根莽草酸平均含量虽也分别高出CK组,但并未与之达到显著差异的程度,与T1组总根莽草酸含量显著低于CK组0.3倍形成鲜明对比;T2和T3组主根、侧根和总根生物量分别均未与CK组达到显著差异,但T1组的侧根、总根生物量却显著高于CK组.相关性分析表明:池杉总根苹果酸与莽草酸含量表现出极显著的正相关(P<0.01);总根莽草酸含量与总根生物量之间则表现出显著的负相关性(P<0.05).  相似文献   

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