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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.
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   

10.
According to the unification principle of system structure and system function of the Water Resource Conservation Forests,seven factors were selected from stand spatial structure,trees structure and healthy of woods,the multifunction management optimization model target was confirmed by using nonlinearity multi-objective programming approach, and the target function-stand spatial structure homogeneity index was defined to establish spatial optimization models with restraining conditions set up in diversity of stand structure and spatial structure.The spatial structure of available typical stand in the wet land area in southern Donting Lake was optimized by means of selective cutting and reinforcement planting.The results showed that the spatial structure was improved obviously and trees diversity and stand health were not weakened.It’s suggested that the established optimization model can effectively guide multifunction management,stand structure optimization and the steadiness of ecological ecosystem and it is convenient and operable in practice,and it’s very important to protect and recover ecosystem of Water Resource Conservation Forests.  相似文献   

11.
泡桐叶片蛋白质多态性及其聚类分析(英文)   总被引:2,自引:0,他引:2  
根据白花泡桐(Paulownia fargesii)、白花兰考泡桐(P.elongata f. alba)、毛泡 桐(P. tomentosa)、川泡桐(P. fargesii)、山明泡桐(P. lamprophylla)、成都泡桐 (P. albiphloea var chengtuensis)、鄂川泡桐(P. albiphloea)、南方泡桐(P. austra lis)、白花泡桐(P. fortunei)、兰考泡桐(P. elongata)叶片蛋白质单向电泳和双向 电泳结果,可将它们聚类分为白花泡桐组(白花泡桐和白花兰考泡桐)、南方泡桐组(南方 泡桐和成都泡桐)和毛泡桐组(毛泡桐、川泡桐、鄂川泡桐、山明泡桐和兰考泡桐)。该结 果为泡桐属植物的分类提供了参考依据,也为泡桐属植物种确立、杂种鉴定和新品种培育奠 定了基础。  相似文献   

12.

In Scandinavia, moose (Alces alces L.) sometimes cause severe browsing damage to economically-important pine. Moose-vehicle accidents have spurred construction of fences along roads, and these may interfere with moose migration between summer and winter ranges, or the road alone may be a barrier. If this happens and moose build up along roads, landowners may suffer economically. Therefore, this study investigated whether roads, fences or other factors influence the use of young pine stands by moose. Eighty stands along roads in northern Sweden were evaluated in which individually-browsed branches were counted on 9972 pines. Moose browsing was not significantly related to birch (Betula pendula Roth, B. pubescens Ehrh.) density, nor did it differ between pines (Pinus contorta Douglas or P. sylvestris L.). However, increased pine density, site productivity and proximity to a highway were associated with increased browsing. Further large-scale studies are needed to understand moose habitat selection and the effects of roads.  相似文献   

13.

The root systems of 2-yr-old Picea glauca, Picea mariana and Pinus banksiana seedlings were submitted to various frost temperatures during an artificial frost to induce different levels of root damage. Frost-damaged and control seedlings were placed in a greenhouse under high and low soil moisture regimes. Seedling growth and physiology were evaluated periodically. Seedling survival was reduced when root damage reached levels of 60-80%. Root systems of all three species showed partial to total recovery by the end of the experiment. In general, root freezing damage caused reductions in seedling growth, with these reductions becoming less significant over time. Root damage had little to no effect on black spruce and jack pine seedling physiology, while white spruce CO 2 uptake decreased with increasing root damage. Shoot nitrogen content of all three species decreased slightly with increasing root damage.  相似文献   

14.
The development, longevity, fecundity and life-table parameters of the endoparasitoid Anagyrus pseudococci (Girault) (Hymenoptera: Encyrtidae), 15 d.o. (3rd-instar nymphs) and 21 d.o. (young adult females) of the vine mealybug, Planococcus ficus (Signoret) (Hemiptera: Pseudococcidae) at 28 ± 1°C, 65 ± 10%RH and 16:8h L:D under laboratory conditions. The developmental time of female parasitoids within the host was 17.7 ± 0.39 days in 15 d.o. and 16.65 ± 0.25 days in 21 d.o. hosts; for males, development time was 16.85 ± 0.29 and 15.25 ± 0.09 days, respectively. The average number of offspring per female was 22.35 ± 1.68 in 15 d.o. and 34.8 ± 2.56 in 21 d.o. vine mealybugs. The longevity of female parasitoids was 14.8 ± 0.98 days in 15 d.o. and 15.65 ± 0.92 days in 21 d.o. mealybugs, respectively; for males, longevity was determined as 7.3 ± 0.43 and 6.7 ± 0.54 days, respectively. The mean time of pupation was 7.85 ± 0.003 days in 15 d.o. mealybugs and 8.65 ± 0.003 days in 21 d.o. mealybugs. The aggregate encapsulation rate in the parasitized 15 d.o. mealybugs was 49.73 and 60.36% in 21 d.o. mealybugs. Furthermore, effective encapsulation was 24.82% in 15 d.o. mealybugs and 37.50% in 21 d.o. mealybugs. Population growth rate (r m) for A. pseudococci was 0.0999 female/female/days in 15 d.o. mealybugs and 0.1269 female/female/days in 21 d.o. mealybugs. The mean population generation time was 23.49 days for parasitoids reared in 15-days-old and 22.39 days when reared in 21 d.o. mealybugs.  相似文献   

15.
There are abundant local legume trees and shrubs potentially suitable for alley cropping systems in the sub-Saharan Africa, which are yet to be studied. The nitrogen contribution of two years old Albizia lebbeck and S. corymbosato yield of maize grown in alley cropping was compared to that of Senna siamea, Gliricidia sepium and Leucaena leucocephala in four seasons at Ibadan. Maize shoot biomass and maize grain yield in A. lebbeck alley compared favourably with that in G. sepium and L. leucocephala. Maize biomass and grain yield in S. corymbosa alleys were the lowest. Within A. lebbeck, L. leucocpehala, and G. sepium alleys there were no significant differences in the maize yield in the alleys that received 0, 40 or 80 kg N/ha. Application of more than 40 kg N/ha in S. corymbosa alleys was not necessary as there was no significant increase in maize yield at the higher level of nitrogen. Maize yield and N uptake in A. lebbeck alleys were not significantly different from yield and N uptake in G. sepium, and L. leucocephala at the same fertilizer level. There was a significant correlation between hedgerow tree biomass and maize grain yield. At the end of twelve weeks after pruning application, the organic residues of the pruning applied in the alleys ranged from 5% in G. sepium and 44% in A. lebbeck in the first year compared with the original pruning applied which showed that the slow rate of A. lebbeck decomposition could have a beneficial effect on the soil. The maize N recovery from applied N fertilizer was low (10–22%). Percentage N recovery from the prunings was low in the non-N fixing trees (12–22%), while the recovery was high (49–59%) in A. lebbeck as well as in the other nitrogen fixing tree prunings. Thus A. lebbeck, apart from enhancing maize growth and grain yield like in L. leucocephala and G. sepium, had an added advantage because it remained longer as mulching material on the soil because of its slow rate of decomposition. It was able to survive pruning frequencies with no die-back. This indicates that A. lebbeck is a good potential candidate for alley cropping system in West Africa. S. corymbosa performed poorly compared with the other legume trees. Though it responded to N fertilizer showing a positive interaction between the hedgerow and fertilizer application, it had a high die back rate following pruning periods and termite attack.This revised version was published online in November 2005 with corrections to the Cover Date.  相似文献   

16.

The root collar diameter and the height:diameter ratio are of particular importance in container-grown seedlings where a high density in the containers may produce spindly seedlings. Temperature regimes and light quality are known to affect plant growth. The aim of this study was to identify responses in Picea abies (L.) Karst. seedlings grown with light providing different red:far-red ratios and under temperature regimes with alternating day (DT) and night temperature (NT) from negative (DT < NT) to positive (DT > NT) difference (DIF) between DT and NT. Experiments were conducted in controlled environment chambers and in a daylight phytotron. Only limited thermoperiodic responses appeared in P . abies seedlings with respect to seedling height and dry weight accumulation. The formation of terminal buds, however, was clearly delayed in seedlings grown at negative DIF. The results indicate a requirement for day extension light that is high in far-red, to prevent terminal bud formation under natural short-day conditions. An extended study should be conducted to clarify the minimum level of light intensity and the optimal light quality needed to prevent terminal bud formation under natural short-day conditions.  相似文献   

17.
Woody vegetation in cultivated landscapes in Burkina Faso is influenced by agricultural activities that are in turn influenced by institutional arrangements. Research was undertaken in a village in south-west Burkina Faso to investigate the relationship between species composition, diversity, density, species accumulation and land use category. Additionally the relationship between number of trees, size of farmed land and farmer ethnicity was investigated. Indigenous Tiéfo farmers had on average more than double the number of large (>4 m) trees of Vitellaria paradoxa Gaertn. f., Parkia biglobosa (Jacq.) R. Br. Ex G. Don and Anacardium occidentale L. than farmers belonging to other ethnic groups, but this was partly explained by a larger area being available. Differences between ethnic groups were not significant when expressed per ha. Botanical inventories of fallows more than 4 years old, cultivated parklands and plantations of Mangifera indica L. and A. occidentale showed that tree density and Simpson’s index of diversity for trees were highest in the fallow. Simpson’s index was not significantly different for regeneration, but sample-based species accumulation curves indicated that species accumulation in parklands was faster than in plantations when expressed per individual. The average regeneration density was 12,605, 1,995 and 6,772 seedlings ha-1 for fallow, parklands and plantations, respectively. This low density for parklands means that species accumulation is slow compared to the other land uses when expressed per unit area. Fallow seems the most efficient way of keeping tree diversity in the agricultural landscape.  相似文献   

18.
In situ produced plant residues contain a mixture of different plant components of varying quality. To assess synergistic or antagonistic interactions occurring during the decomposition and mineralization of such mixtures, individual plant parts (stems, leaves, leaf litter and roots) or the mixture of stems, leaves and leaf litter of the agroforestry species pigeonpea (Cajanus cajan) or of crop residues of peanut (Arachis hypogaea) or of the weed hairy indigo (Indigofera hirsuta) were incubated in pots for 19 weeks. Periodically, remaining plant residues were sieved out (>2 mm), weighed and N content as well as soil mineral N determined. Above- and below-ground residues of peanut decomposed fastest and showed the largest N release in agreement with their high N concentration and low-acid detergent fibre (ADF) : N ratio. Hairy indigo was hypothesized to be of lower quality than pigeonpea because of its high-polyphenol content. However, it decomposed faster than pigeonpea, largely because of the higher N and lower lignin concentration of its components. Ranking of individual plant components for N mineralization resulted in the following pattern, leaves > leaf litter > roots > stems. In mixtures of the different plant components a similar species order in decomposition was obtained, e.g. peanut > hairy indigo > pigeonpea. The amount of N released from the mixture was dominated by stem material that comprised 46–61% of the mixture. The interactions in mixtures were relatively small for peanut (generally high-quality components) as well as for pigeonpea (low proportion of high-quality components, i.e. N rich leaf material). However, a positive interaction occurred during later stages of N mineralization in the mixture of hairy indigo as it had a significant proportion of N rich components and absence of highly reactive polyphenols. Thus, for plants with low to intermediate chemical quality attributes, manipulating plant composition (e.g. by varying harvest age, affecting stem and leaf proportions) will be important to obtain significant interactions during decomposition when its components are mixed.  相似文献   

19.
During 7 years (1979–1985) cacao harvests (beans and husks) have been recorded for the agroforestry systems ofTheobroma cacao underCordia alliodora andErythrina poeppigiana shade trees. The mean oven dry cacao yields were 626 and 712 kg.ha–1.a–1 cocoa beans underC. alliodora andE. poeppigiana respectively. Harvests have gradually increased over the years and the plantation has now reached maturity.Annual extraction of N, P, K, Ca and Mg in fruits, which is relatively small, was calculated on the basis of chemical analyses. The following average values were found (kg.ha–1.a–1): At the age of 8 years, theC. alliodora trees have reached 26.7 cm diameter (DBH) and 14.0 m in height. Mean annual growth (from age 5 to 7) is 14.6 m3.ha–1.a–1.Natural plant residue production has been measured for 4 years (Nov. 1981–Oct. 1985). UnderE. poeppigiana it has reached a value of 8.91 t.ha–1.a–1 and underC. alliodora 7.07 t.ha–1.a–1. The shade trees have contributed 57 and 47% respectively. Transference and decomposition rates are high and important in the nutrient cycles.The nutrient content of the litter was analysed and corresponding average yearly transfers were (kg.ha–1.a–1): For part I see Vol. 4, No. 3, 1986.Agroforestry Project, CATIE/GTZ (Tropical Agricultural Research and Training Center/Gesselschaft für Technische Zusammenarbeit), Turrialba, Costa Rica  相似文献   

20.
Thaumetopoea solitaria is a serious pest of pistachio throughout the Mediterranean and the surrounding region. In this study, contact and ingestion toxicities of Bifora radians, Fumaria officinalis, Humulus lupulus and Rhododendron ponticum extracts against T. solitaria larvae were examined under laboratory conditions. Dimethoate was used as a positive control. In the contact toxicity bioassays B. radians extract was the most toxic, causing 32% mortality. In the ingestion toxicity bioassays H. lupulus extract was the most active, causing 83% mortality after 48 h. This shows that H. lupulus is acting as a stomach poison. The LC50 and LC90 values for H. lupulus ingestion toxicity bioassays were 1.7 and 8.7%, respectively. The LT50 value was 29.3 h. Since H. lupulus extract caused >50% mortality even 6 days after application, its long lasting residual effect promises fewer applications. These results imply that H. lupulus has potential for use as a crop protectant against T. solitaria.  相似文献   

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