Understorey vegetation in young naturally regenerated and planted birch (Betula spp.) stands on abandoned agricultural land     

Tea Tullus  Arvo Tullus  Elle Roosaluste  Ants Kaasik  Reimo Lutter  Hardi Tullus 《New Forests》2013,44(4):591-611

The abandonment of agricultural lands in Northern and Eastern Europe increases the area covered by first generation forests, which are either formed as an outcome of secondary succession or established as plantations. However, questions remain as to how these new stands develop and what kind of species they favour, which in turn has impacts on their ecological and economical value. Our aim was to compare understorey vascular plant and bryophyte vegetation characteristics between naturally regenerated and planted birch stands on abandoned agricultural sites in Estonia, focusing on the aspects of species richness and forest understorey recovery. Species richness and diversity of vascular plants were similar in both stand types but the number of forest vascular plant species was significantly higher in naturally regenerated stands. The bryophyte layer of naturally regenerated stands had a higher species richness, diversity, and number of forest bryophyte species. The higher number of forest vascular plant and bryophyte species in naturally regenerated stands can be explained by the longer undisturbed succession period. The recovery of the forest understorey was unaffected by former agricultural land use (crop field or grassland). The influence of soil properties on the recovery of the forest understorey was not detected, but the number of vascular plant species that grow in forests as well as in grasslands was negatively correlated with distance from forest. Overall, understorey vegetation of natural and planted birch stands did not reveal substantial differences. However, in the case of vigorous natural birch regeneration in the vicinity of forest land, unassisted reforestation should be favoured.  相似文献   

Genetic Diversity of Tea Plant （Camellia Sinensis （L.） O.Kuntze） in Wuling Mountainous Area Revealed by ISSR Marker     

Yue Zhang  Li Lu  Saiyan Yuan  Xin Pang  Wei-Dong Wang  Lin Zhou  John  K  Tanui  Xing-Hui Li 《茶叶》2013,(4):205-211

Genetic diversity and relationship of 183 tea germplasms were assessed by inter-simple sequence repeat （ISSR） marker.The study optimized the ISSR-PCR system for tea plants.Results show that genetic similarity among 183 tea ascensions was between 0.52-0.93,indicating a wide gene pool and a broad genetic variation of Wuling tea resources.The highest similarity of all materials between No1 and No2 was 0.93.Dendrogram of the 183 tea germplasms were protracted by UPGMA clustering analysis also revealed the genetic diversity and relationship of the tea germplasms of Wuling mountainous area.Besides,fingerprint of the 183 tea germplasms were constructed.  相似文献   

贵州省茶园蜘蛛区系研究   总被引：2，自引：0，他引：2  

戴轩  韩宝瑜 《贵州茶叶》2009,37(2)

记述了贵州茶园蜘蛛25科203种,其中优势类群园蛛科48种,跳蛛科25种,肖蛸科22种,平腹蛛科13种,蟹蛛科13种,球腹蛛科12种,狼蛛科10种.在我国动物区划中,贵州境内大部分地区属于华中区的西部山地高原亚区。仅西部少数地区属于西南区的西南山地亚区。结合茶树适生格局。把蜘蛛区系划分为：黔中山地丘陵区（Ⅰ）、黔东低山丘陵盆地区（Ⅱ）、黔南低山河谷区（Ⅲ）、黔北中山峡谷区（Ⅳ）、黔西高原中山区（Ⅴ）。Ⅰ区20科139种,优势种为角因蛛、黄褐新园蛛、灌木新园蛛、青新园蛛、悦目金蛛和红高亮腹蛛,特殊种：贵州花蟹蛛、中华刺足蛛、桐庐指蛛和四点亮腹蛛。Ⅱ区25科183种,优势种为角园蛛、黄褐新园蛛、悦目金蛛、棒络新妇、前齿肖蛸、锥腹肖蛸和草间小黑蛛,特殊种：武陵银鳞蛛、王氏银鳞蛛、森林桂齐蛛、四斑粗螯蛛和;门狂蛛等。Ⅲ区13科77种,优势种：角园蛛、黄褐新园蛛、悦目金蛛、前齿肖蛸、锥腹肖蛸和草间小黑蛛。Ⅳ13科73种,优势种：角园蛛、黄褐新园蛛、悦目金蛛、前齿肖蛸、锥腹肖蛸和草间小黑蛛。V13科60种,优势种：角园蛛、黄褐新园蛛、前齿肖蛸、锥腹肖蛸和草间小黑蛛。蜘蛛是茶园重要捕食性昆虫天敌。  相似文献   

Above-ground growth and temporal plant–soil relations in midterm hybrid aspen (Populus tremula L. × P. tremuloides Michx.) plantations on former arable lands in hemiboreal Estonia     

Reimo Lutter  Arvo Tullus  Arno Kanal  Tea Tullus  Hardi Tullus 《Scandinavian Journal of Forest Research》2017,32(8):688-699

Short-rotation forestry with hybrid aspen is a novel silvicultural system in northern Europe on former arable lands. However, knowledge about hybrid aspen growth potential in different soil types and the impact of soil physico-chemical properties on tree productivity in the long term is still scanty. We used repeated monitoring of soil properties and tree growth in young (5-year) and midterm (15-year) hybrid aspen plantations in various soil types (corresponding to four forest site types) to determine the temporal changes in tree growth–soil relationships. Growth of midterm hybrid aspen plantations exceeded same-aged native European aspen stands about two-fold. Growth had improved on Aegopodium, remained moderate on moist Dryopteris and was increasingly suppressed on dry Hepatica soils. The pH_KCl, available Ca, content of clay and layer thickness of the soil A-horizon had a significant effect on tree growth in young plantations, but these effects disappeared in the midterm age. The soil water-holding capacity and available P in the A-horizon had a significant growth-controlling effect on tree growth in both ages. We concluded that former arable soils provide a sufficient supply of major nutrients in midterm hybrid aspen plantations whereas minor changes have occurred in growth–soil relationships between young and midterm age.  相似文献   

RNA介导的转录后基因沉默     

余有本  江昌俊  李叶云 《分子植物育种》2004,2(2):259-267

  相似文献   

茶鲜叶匀浆悬浮发酵工艺监测参数   总被引：3，自引：0，他引：3  

夏涛 《茶叶科学》1999,19(1):47-53

采用电极法对茶鲜叶匀浆悬浮发酵过程中的氧化还原电位（ＯＲＰ）、溶解氧（ＤＯ）浓度工艺参数进行了在线检测。结果表明,发酵体系中多酚类物质消耗与ＯＲＰ的变化呈显著负相关。随着多酚类物质氧化消耗及氧化产物的形成,ＯＲＰ呈逐步增高,其变化曲线呈“Ｓ”型,符合Ｌｏｇｉｓｔｉｃ方程,方程拐点可间接反映多酚类物质的保留量;ＤＯ浓度影响发酵速率和红茶品质,其变化趋势也符合Ｌｏｇｉｓｔｉｃ方程描述的“Ｓ”型曲线,而方程拐点略早于茶黄素（ＴＦｓ）峰值出现时间,故可用ＤＯ浓度变化指示ＴＦｓ变化过程。发酵体系总色度（ＴＣ）变化与茶红素（ＴＲｓ）形成趋势较吻合,凡影响ＴＲｓ形成的因素均影响ＴＣ。  相似文献   

安吉白茶特异性状的生理生化本质   总被引：18，自引：1，他引：17  

成浩 《茶叶科学》1999,19(2):87-92

安吉白茶的特异性主要表现在春季发芽时新梢嫩叶叶色的可逆性白化现象, 在白化过程中新梢的叶绿素含量急剧下降和氨基酸含量显著上升。研究表明, 安吉白茶是一个温度敏感的自然突变体, 其白化表达的温度阈值在20 ～22 ℃之间, 但该温度仅在芽萌发初期发挥作用; 其正常复绿的启动温度在16 ～18℃之间。叶片白化期的主要生理生化变化是叶绿体膜结构发育发生障碍, 叶绿体退化解体, 叶绿素合成受阻, 质体膜上各种色素蛋白复合体缺失, 导致了叶色的变化; RuBP羧化酶的大、小亚基含量及酶活性下降, 同时伴随蛋白水解酶活性的升高, 终因叶绿体不能继续发育, 多余的可溶性蛋白水解, 导致游离氨基酸含量显著上升。文中对其返白机理进行了讨论, 认为该温度敏感型突变体的突变很可能是由核基因或核质互作控制的。  相似文献   

利用AFLP技术鉴定凤凰单丛古茶树种质资源     

晏嫦妤  李家贤  黄建安  赵超艺  黄华林  唐颢  罗军武 《广西农业生物科学》2009,(1):89-93

本文采用AFLP技术对34个凤凰单丛古茶树资源进行了种质鉴定分析。结果显示,筛选出多态性较高的5对引物中,引物组合E41M42、E41M39和E41M33可鉴别出供试的全部资源,鉴别效率为100％;有23份资源具有特异带,占供试材料的67．6％。由此研究表明,AFLP技术可以通过特异带、特异的谱带类型、不同引物提供谱带的组合将凤凰单丛古茶树资源区分开来,这对保护凤凰单丛古茶树资源的育种产权、登录新品种、鉴定和检测其种子与苗木的真实性和纯度具有重要的现实意义。  相似文献   

Effects of meloxicam on the haemostatic profile of dogs undergoing orthopaedic surgery     

Kazakos GM  Papazoglou LG  Rallis T  Tsimopoulos G  Adamama-Moraitou K  Tea A 《The Veterinary record》2005,157(15):444-446

The buccal mucosal bleeding time (BMBT), prothrombin time (PT), activated partial thromboplastin time (APTT) and intraoperative bleeding score (IBS) of 38 dogs that underwent orthopaedic surgical procedures and received meloxicam orally and/or parenterally were measured. Fourteen of the dogs (group A) received a single subcutaneous dose of 0.2 mg/kg meloxicam at premedication, 18 dogs (group B) received 0.1 mg/kg meloxicam orally daily for five days followed by a single subcutaneous dose of 0.2 mg/kg meloxicam preoperatively, and six dogs (group C) received 0.5 ml of normal saline subcutaneously at premedication. No statistically significant differences among the groups were detected in relation to the mean (SD) values of BMBT, PT and IBS before and after the surgery, or in the values of APTT in group A. In group B there was a small but significant increase in APTT after the surgery, but all the measurements were within the normal range for dogs.  相似文献   

Comparison of Various Digestion and Extraction Procedures in Analysis of Heavy Metals in Sediments     

Ščančar  Janex  Milačič  Radmila  Horvat  Milena 《Water, air, and soil pollution》2000,118(1-2):87-99

Sediment analysis is very important ininvestigations of the heavy metal burden in theenvironment. In the present work various digestion andextraction procedures were evaluated in order toassess the extent of contamination with heavy metalsin sediments from the Moste hydroelectric reservoir.Total acid dissolution, aqua regia digestion andacetic acid extraction procedures were applied tosamples. Zn, Cd, Pb, Co, Ni, Cu and Cr were determinedby flame or electrothermal atomic absorptionspectrometry (FAAS, ETAAS) under optimized measurementconditions. A comparison of total acid dissolutionincluding hydrofluoric acid (HF) treatment and theaqua regia soluble fraction was made to estimatethe applicability of aqua regia digestion inanalysis of total metal concentrations in sediments.In general, good agreement of the results was observedfor Co, Pb, Cu and Zn, however for Cr, Ni and Cdsignificantly lower results were obtained in the aqua regia soluble fraction. In addition, an extraction procedure using 25% v/v acetic acid wasapplied for estimation of the extent of contaminationwith heavy metals originating from anthropogenicactivities. The results indicate that the sedimentsupstream of the reservoir are not contaminated, whilethe sediments from the hydroelectric reservoir showsa significant anthropogenic input of Ni, Zn and Pb,which corresponds well with pollution sources.  相似文献