栎链蚧属一新种(蚧总科,链蚧科)     

刘玉升  张之光 《山东农业大学学报(自然科学版)》1989,(2)

本文记述栎链蚧属一新种——长白山栎链蚧Asterodiaspis changbaishan(?)nsi(?)sp. nov, 对其雌成虫和一龄若虫的形态分别进行了详细描述并有附图。  相似文献   

Competition for inorganic and organic N by blue oak (Quercus douglasii) seedlings, an annual grass, and soil microorganisms in a pot study     

Xiaomei Cheng  Caroline S Bledsoe 《Soil biology & biochemistry》2004,36(1):135-144

Sources of competition for limited soil resources, such as nitrogen (N), include competitive interactions among different plant species and between plants and soil microorganisms (microbes). To study these competitive interactions, blue oak seedlings (Quercus douglasii) were grown alone or grown together with an annual grass, wild oats (Avena barbata) in pots containing field soil. We injected ¹⁵N-labeled ammonium, nitrate or glycine into the soil of each pot and harvested plants 5 days later. Plant shoots and roots, soil microbial N and soil KCl-extractable N were analyzed for ¹⁵N content. When oak and grass were grown together, ¹⁵N recovery from the inorganic N treatments (NH₄⁺, or NO₃⁻) was 34, 9 and 4% for the grass, microbes and oak seedlings, respectively, and only 1% remained as KCl-extractable N. ¹⁵N recovery from the glycine treatment was 18, 22, 5% for the grass, microbes and oak seedlings, respectively, and 4% remained as KCl-extractable N. When oaks were grown alone, ¹⁵N recovery by soil microbes was 21, 48 and 40% in the NO₃⁻, NH₄⁺ and glycine treatments, respectively. N forms had no effects on ¹⁵N recovery in oak seedlings (7%) and in KCl-extractable N pool (13%). In general, total N recovery by the grass was much greater than by oaks. However, on a fine root surface area or length basis, oaks exhibited higher N uptake than the grass. Our results suggest that the high rooting density and rapid growth rate of the annual grasses such as Avena barbata made them superior competitors for available soil N when compared to blue oak seedlings and to microbes. Soil microbes were better competitors for organic than inorganic N when annual grasses were present, but preferred NH₄⁺ when competing only with oak seedlings.  相似文献   

Seasonal pattern of total soil respiration in undisturbed and disturbed ecosystems of Central Himalaya   总被引：1，自引：0，他引：1  

Mukesh Joshi  G. S. Mer  S. P. Singh  Y. S. Rawat 《Biology and Fertility of Soils》1991,11(4):267-272

Summary The rates of CO₂ efflux were measured by an alkali absorption method (using 20 ml 0.5 N NaOH) from soils in four undisturbed sites [two evergreen oak forests, Quercus floribunda Lindl. (tilonj oak), Quercus leucotrichophora A Camus (banj oak), and two evergreen conifer forests, Cedrus deodara Loud. (deodar forest) and Pinus roxburghii Sarg. (chir pine forest)] and three disturbed sites. The sites were located between elevations of 1850 and 2360 m in the Central Himalaya. The seasonal pattern of soil respiration was similar in all the sites with a maximum during the rainy season, intermediate rates during the summer season and the lowest level of activity in winter. The rate of CO₂ efflux was higher in broadleaf than in conifer forests, and it was lowest in the disturbed sites. Among the edaphic conditions, soil moisture, N, organic C, pH, soil porosity, and root biomass positively affected total soil respiration. The proportion of root respiration to total soil respiration was higher in the disturbed sites than the undisturbed sites in winter. Conditions in the winter season were less favourable for microbial respiration than for root respiration.  相似文献   

耕牛栎属树叶中毒防治的研究现状     

王成章  林东康 《河南农业大学学报》1994,(4)

本文根据国内耕牛对栎属树叶中毒的报道，分析了栎叶中毒的规律、机理、诊断及防治方法，为该病的防治提供了依据。  相似文献   

坡向和坡位对大兴安岭干旱阳坡蒙古栎林温湿度的影响   总被引：2，自引：0，他引：2  

丁永全 《东北林业大学学报》2015,(4):46-51

于2012年5月中旬至10月初,在大兴安岭干旱阳坡的蒙古栎林内,选择不同的坡向和坡位设置观测样地定点测定土壤温度、空气温湿度和土壤含水量。分析结果表明:不同坡向土壤温度由大到小为南坡、西南坡、东南坡,气温由大到小为西南坡、南坡、东南坡,空气湿度和土壤含水量由大到小均为东南坡、西南坡、南坡;南坡空气和土壤温度由大到小为坡上、坡下,土壤含水量坡下大于坡上含水量,空气湿度坡上大于坡下湿度;空气和土壤温湿度受空间位置和季节分布影响差异较大,不同坡向和坡位土壤温湿度差异明显,不同季节空气温湿度波动较大。  相似文献   

Establishing grazing and grazing-excluded patches increases plant and invertebrate diversity in a Mediterranean oak woodland   总被引：1，自引：0，他引：1  

Miguel N. Bugalho  Xavier Lecomte  Merícia GonçalvesMaria C. Caldeira  Manuela Branco 《Forest Ecology and Management》2011,261(11):2133-2139

Grazing is a global, dominant land use affecting biodiversity and ecosystem processes. In Mediterranean ecosystems grazing is a major ecological and evolutionary driver but, surprisingly, there is little information on the use of grazing as a tool to manage biodiversity in these ecosystems. We conducted an experiment to assess if establishing grazing and small scale grazing-excluded areas would increase plant and invertebrate diversity in a Mediterranean evergreen oak woodland. Plant community traits were different between treatments. Biomass of herbs (176.7 ± 18.3 g m⁻²vs 100.4 ± 10.6 g m⁻²) and litter (291.0 ± 38.3 g m⁻²vs 186.8 ± 26.4 g m⁻²), as well as the total cover of legumes (0.83 ± 0.05 vs 0.91 ± 0.03) were higher, and the proportion of bare ground (0.83 ± 0.05 vs 0.91 ± 0.03) was lower, in ungrazed plots. There were no differences in the number of plant species between treatments. Some plant species and invertebrate taxa were recorded exclusively in grazed or ungrazed plots. Invertebrate detritivores and sap sucking insects were more abundant in ungrazed plots. Ant assemblages were functionally different between treatments: Honeydew-gatherer ants were associated with ungrazed and higher plant biomass plots, and seed-eaters as well as aggressive predator ant species were associated with grazed, open habitat, plots. Management practices that maintain grazing and small scale grazing-excluded areas can increase habitat heterogeneity and promote herbaceous plant and invertebrate diversity at the local level.  相似文献   

QRS脱毒剂防治耕牛栎叶中毒试验的研究     

林东康  侯安祖 《河南农业大学学报》1993,27(4):399-403

作者在研究栎叶中单宁含量及其脱毒方法的基础上,通过近二年的试验,研制出防治耕牛栎叶中毒的脱毒剂ＱＲＳ。结果证明：该脱毒剂无毒副作用,能脱去栎叶中有毒物质单宁,可有效地预防耕牛早春栎叶中毒,而且有显著的治疗效果。  相似文献   

QRS栎属树叶脱毒剂脱毒效果及推广应用试验报告     

吕宝珊  赵明甫 《中国牛业科学》1995,21(4):37-39

本试验表明，该脱毒剂对耕牛无毒副作用。脱毒效果确实可靠，且价格低廉，具有重大的推广应用价值及良好的经济效益和神经效益，该脱毒剂的研制成功，为山区栎叶资源的充分利用开辟了新途径，对促进畜牧业的发展有着重要意义。  相似文献   

影响栓皮栎等造林成活因素的研究   总被引：1，自引：0，他引：1  

郑均宝  于力  王德艺 《河北林果研究》1990,(1)

本文叙述了筛选影响栓皮栎等造林成活因素数量化方法,利用Basic程序在Corona微型电子计算机上进行计算,得到最优回归方程。基准变量y为每亩地上栎树的穴数,影响基准变量的因素保留了x_1(土层厚度)、x_2(土壤受侵蚀程度)、x_4(草本植物盖度)。并对有显著影响的因素进行了分析。本文还探讨了土壤受侵蚀程度与土层厚度,以及土层厚度与每亩地栎树保存穴数两组一元线性回归方程,并计算了相关系数。这样,便科学地论证了在河北燕山东段的栓皮栎等的造林地选择条件,以及合理的播种造林密度问题。  相似文献   

农杆菌携带柞蚕抗菌肽基因转入桑树的研究   总被引：23，自引：5，他引：18  

管志文  谭智达 《蚕业科学》1994,20(1):1-6

人工合成柞蚕抗菌肽Ｄ基因通过根癌农杆菌Ｔｉ质粒载体转入桑树叶盘，获得基因转化工程苗。柞蚕抗菌肽对桑树青枯病假单孢菌有明显杀菌作用。人工合成柞蚕抗菌肽基因导入农杆菌感染桑树叶盘并诱导成苗。经卡那霉素筛选，胭脂碱电泳检测及抗菌肽基因探针进行印迹点杂交，确认抗菌肽基因转化桑苗成功，为培育抗青枯病品种打下基础。  相似文献