[Objective] Plant resources of the Micang Mountain Nature Reserve in Shaanxi Province were identified through field survey. This investigation provided a theoretical basis for the study of the flora of Shaanxi Province, and was of great significance for the protection and utilization of plant resources in Shaanxi Province. [Methods] One newly recorded genus and four newly recorded plants in Shaanxi Province were determined by consulting the literature and comparing the specimens in collections. [Results] One newly recorded genus of the vascular plants, Gonocarpus Thunberg, and its newly recorded species Gonocarpus micranthus Thunberg in Shaanxi Province were determined. In addition, three newly recorded plants were found, including Viburnum atrocyaneum C. B. Clarke (Viburnaceae), Carpesium minus Hemsley (Asteraceae), and Euonymus oxyphyllus Miquel (Celastraceae). [Conclusion] This study improves the records of vascular plants in Shaanxi province. The voucher specimens are stored in the herbarium of Northwest A&F University (WUK).

Prediction of the potential distribution of species based on the data of its current distribution in combination with climatic variables is important for understanding species evolution and reasonable conservation. Based on 220 distribution sites in China and 12 low-correlation climatic variables, we analyzed the potential distribution of Paris verticillata at present and future (2050s and 2070s) using the MaxEnt model and ArcGIS program. Further, we analyzed the dominant driving factors for its geographic distribution. The results showed that the area under the curve indices (AUC) was 0.940, with high prediction accuracy. The potential suitable regions of P. verticillata were mainly distributed in the Greater Xing'an Mountains, the Xiao Xing'an Mountains, the Changbai Mountains, the Qinling-Daba Mountains, Hebei, Shanxi and north Shandong under current climate scenario. Those regions accounted for 18.1% of the total suitable area in the country, of which the highly suitable areas accounted for 7.0% and the lowly suitable area 11.1%. The total suitable areas of P. verticillata in the 2050s and 2070s would decline under the climate change scenarios of RCP 2.6, RCP 4.5, RCP 6.0 and RCP 8.5. The highly suitable area would decline, but the lowly suitable area would increase. With the global climate change, both the range and the geometric center of its distribution would gradually spread to higher altitude in the northeast. The cumulative contributions of four dominant factors reached as high as 89.2%, namely, precipitation of wettest month, mean annual temperature, isothermality, and precipitation of January. Their appropriate ranges were 100-275 mm, -0.1-16 ℃, 21-35 and 3-14 mm, respectively.

通过多元回归树(MRT,multivariate regression trees)对太白山自然保护区典型森林群落进行数量分类,采用典范对应分析(CCA,canonical correspondence analysis)进行排序,并对分类得到的森林群落总体多样性进行分析.研究表明:(1)对30个样地进行MRT分类,经交叉验证得出太白山自然保护区典型森林群落可以分为6类.(2)CCA排序揭示了群落的生境分布范围,并反映了太白山森林群落与环境因子的关系,研究表明,海拔、坡度、枯落物厚度和干扰情况4个变量对本研究区群落分布有显著影响.(3)位于中海拔区域森林群落的3种总体多样性指数均较高,而位于高海拔和低海拔区域森林群落的3种总体多样性指数相对较低.

Disturbance is the driving force of forest succession, which can change forest structure and surface vegetation. Disturbance also affects rodent-mediated seed dispersal. In this study, numbered plastic tags were used to examine the responses of rodent dispersal behavior to the fates of Quercus aliena var. acuteserrata acorns at three habitats formed by different artificial disturbances in pine-oak mixed forests in the Qinling Mountains, i.e., unlogged stand, stand in the third year after tending thinning, and bare land. The results showed that seed removal rate from stands in the third year after tending was significantly higher than that in the other two habitats. The proportion of predation in bare land was significantly lower than that in the unlogged stand (25.0%) and in the stand in the third year after tending thinning (36.3%). In the third year after tending thinning, the seed predation rate after seed moving was significantly higher than those in the unlogged stand (17.3%) and bare land (5.0%). Moreover, the proportion of scatter hoarding after removal was also highest in the stand in the third year after tending thinning (4.3%). The longest average dispersal distance (26 m) occurred in the stand in the third year after tending thinning, which was significantly longer than those at the other two habitats. Therefore, the different habitat types significantly influenced the initial seed dispersal process by rodents, with consequences on the rates of seedling establishment. Habitat types affected the foraging strategies of rodents, thereby leading to different seed dispersal modes and natural regeneration patterns in the forest.

采用多元回归树（MRT）对秦岭山地天然次生林群落进行数量分类,采用典范对应分析（CCA）进行排序,分析了秦岭山地天然次生林群落物种多样性沿海拔梯度的变化规律。结果表明:（1） 275个样方共有种子植物195种,隶属61科128属。乔、灌、草3个层次物种多样性变化沿海拔梯度的变化趋势基本一致,呈单峰模型;（2）经交叉验证认为秦岭山地天然次生林群落可分为2类,Ⅰ冬瓜杨（Populus purdomii）+陇东海棠（Malus kansuensis）+蛇莓（Duchesnea indica）群落,Ⅱ锐齿槲栎（Quercus aliena var. acuteserrata）+黄栌（Cotinus coggygria）+茜草（Rubia cordifolia）群落;（3） CCA排序结果揭示了群落生境的分布范围,反映出生态轴的排序意义,较好地反映秦岭山地天然次生林群落与环境因子的关系,其结果表明,海拔、坡向、凋落层厚度和干扰情况4个变量对该地区次生林群落的分布有较大的影响。

[目的]探讨陕西米仓山巴山冷杉天然林群落的物种多样性及种群分布格局,为巴山冷杉天然林可持续保护及有效管理提供理论依据.[方法]在米仓山巴山冷杉天然林集中分布的上干河沟两侧和塔子坪大垭豁等地共设置9个25 m×20 m的样地,通过典型样地调查,从巴山冷杉林群落乔木层、灌木层、草本层的重要值、丰富度(S)、Shannon-Wiener多样性指数(H＇)、Pielou均匀度指数(J)和Simpson优势度指数(D)及乔木径级结构等方面,分析巴山冷杉天然林群落物种多样性及多样性指标间的相关性;应用理论分布模型和方差均值比率(v/m)、聚集指数(Ci)、平均拥挤度(m*)、Green指数(Gi)、聚块性指数(Pai)和聚集强度(Pi)等指标,分析主要优势种的空间分布格局.[结果]乔木层中巴山冷杉(Abiesfargesii)的重要值为59.14％,为建群种,但其胸径＜2.5 em(径级I)的幼苗个体数量严重不足,种群结构衰退.巴山冷杉林乔木层、灌木层、草本层的物种数分别为12,26和53种,各林层的物种多样性差异较明显,灌木层、草本层的H＇分别为2.55和3.50,均大于乔木层的1.58;J和D值也表现为草本层＞灌木层＞乔木层.种群空间分布分析结果表明,巴山冷杉的v/m为16.95,聚集强度为2.50,属于聚集分布类型,另有乔木层的5个优势种、灌木层的4个优势种和草本层的10个优势种也服从聚集分布,少数优势种则呈均匀或随机分布.[结论]陕西米仓山巴山冷杉天然林群落植物种类比较丰富,林分郁闭度较高,不利于幼苗天然更新及幼树生长,群落已经处于演替后期.

We analyzed the interspecific association among 20 dominant populations in shrub layer in secondary natural forest of Pinus tabuliformis in Qinling Mountain, China, with X-test, the association coefficients and the percentage of common occurrence. The results showed that the species pairs with significant positive associations accounted for only 7.4% of the total 190 species pairs. The species pairs such as Lespedeza bicolor and Elaeagnus pungens, Toxicodendron vernicifluum and Pinus tabuliformis, Euonymus alatus and Cerasus tomentosa had extremely significant positive correlations, whereas most of the species pairs showed weak interspecific association. The ratio of positive and negative correlations was less than 1. The results suggested that the interspecific association was relatively weak. Species were with certain independence among dominant populations. Community structure was at an unstable mid-stage with dynamic succession. According to the interspecific association and cluster analysis, combined with biological and ecological characters, the 20 dominant populations in shrub layer were classified into four functional groups. The ecological requirement and resource use pattern of species within the same functional groups were similar, exhibiting a close connection between the shrub species. The connection between different functional groups was relatively loose.

采用样方法对秦岭马头滩四种典型次生林林下植被进行了群落调查和物种多样性分析.表明物种多样性排序,华山松林＞锐齿栎林＞冷杉林＞红桦林.结论:林下物种多样性的提高,增加了林下植被的服务功能,促进了乔木层的更新速度.要提高次生林自我更新能力,可采取间伐、整枝、补植等人工措施,改善其林下群落结构,提高林地生产力和生态功能.

[Objective] Species diversity and impact factors of 6 typical natural forest communities in Shaanxi Micangshan Nature Reserve were studied to further understand the growth and development of species in protected areas and reveal the regeneration of typical communities.[Method] Through the typi cal sampling method,this study investigated species diversity of 6 typical natural forest communities (Tsuga chinensis community,Pinus massoniana community,Juglans mandshurica community,Zelkova schneideriana community,Pinus tabuliformis community,and Quercus variabilis community) from richness,evenness,species diversity index and dominance index.[Result] The numbers of species in P.massoniana community and P.tabuliformis community in tree layer,shrub layer and herb layer were 14,32,16 and 17,50,51 respectively.The numbers in Z.schneideriana community,T.chinensis community and Q.variabilis community in tree layer,shrub layer and herb layer were 11,12,12;7,15,11;and 4,15,14,respectively.The numbers in J.mandshurica community in tree layer,shrub layer and herb layer were 1,4 and 14,respectively.There were obvious differences among species diversity in tree layer,shrub layer and herb layer of the six communities,and the diversity indexes of shrub layer and herb layer were greater than that of tree layer.Species similarity index was generally low between different communities.P.tabuliformis community had the most abundant species in all layers and the dominance indexes were also greater than the other five.The dominant species of J.mandshurica community were outstanding in each layer,while the dominant species of T.chinensis community and Q.variabilis community were obvious in tree layer.P.tabuliformis community and P.massoniana community had abundant plant species diversity in all levels.P.massoniana community,J.mandshurica community and Q.variabilis community had rich seedlings and saplings of constructive species in shrub layer.[Conclusion] T.chinensis community was on top of succession stage,and communities were quite stable.P.tabulaeformis community and P.massoniana community were rich in species and relatively complicated,so that the forest structure was stable.P.masso niana community,J.mandshurica community and Q.variabilis community had great potential for natural regeneration.Thus,it is vital to strengthen the protection on these natural forest communities.

Different types of seeds could be dispersed in various ways.Rodents show a significant preference in the microhabitats of predation sites and caching methods after seeds removal.Understanding the relationship between storing behavior and microhabitat is the key to study seedling establishment.The objective of this study was to reveal the effects of small rodents on seed dispersal patterns of constructive species in pine-oak mixed forests.Field experiments were conducted in the Huoditang forest region in the middle of the Qinling Mountains,Shaanxi Province,northwestern China.Coded plastic tags were used to study the seed fates of Quercus aliena var.acuteserrata,Pinus tabuliformis,and Pinus armandii.The results showed that the in situ seed predation rate of P.tabuliformis seeds was significantly higher than the seeds of the other three types of seeds.P.armandii seeds had the highest predation rate (60％) and cache rate (4.33％) after removal by rodents,and the longest average dispersal distance of predation sites (2.49 m).The small acorns of Q.aliena var.acuteserrata had the longest dispersal distance of cache sites after removal by rodents (4.92 m).All types of seeds except P.armandii seeds had over 85％ of the sites were used as predation sites.P.tabuliformis seeds had no cache sites.Over 90％ of the cache sites of the other three types of seeds contained a single seed.Most of the seeds were discarded after removal by rodents.The proportions of seeds that were cached under shrubs were higher for large and small acorns of Q.aliena var.acuteserrata and P.armandii seeds,which were 87.5％,78.57％ and 53.33％ of the total number of seeds after cache by rodents,respectively.A lower proportion of seeds was cached on bare land.Most of seeds were eaten under shrubs.Only P.armandii seeds were eaten in the holes after removal by rodents.A higher proportion of P.tabuliformis seeds were eaten in situ than the other three types of seeds.Except P.tabuliformis seeds,the predation rates for the other three types of seeds tended to decrease along microhabitat changing from simple to complex (shrub to grass to shrub edge to bare land).The nutritive value of the seeds and the cost of the rodents' predation and removal process were the key factors affecting the fates of seeds,and rodents showed obvious preference in the microhabitats of seed storage and predation sites.

2015年在太白山保护区南天门和小文公庙两处太白红杉林分布集中区域,选择小生境一致的地区分别设立2个监测样地,并和2009年的调查样地重叠,对太白红杉天然林群落物种多样性及林分结构进行动态监测,以期探明生物多样性的变化规律及主导性作用因子,为太白红杉天然林保护及可持续经营提供科学参考.

为了深入分析环境因子对湿地CH4排放产生的影响,利用中型试验生态系对若尔盖典型泥炭地开展地下水位和土壤温度控制试验,比较不同条件下泥炭地2012年生长季(5-10月)CH4排放通量的月变化情况.结果表明:高水位(土壤表面0 cm)下CH4排放通量最高,中水位(地表以下10 cm)下次之,低水位(地表以下20 cm)下最低;其中,10月CH4排放通量变化不明显,不同地下水位下泥炭地的CH4排放通量均在7月达到最大值,并且均呈明显的单峰曲线,高、中、低地下水位下CH4排放通量平均值分别为6.263 3、4.754 4和3.949 8 mg/(m2·h).而且,在一定温度范围内,不同地下水位条件下CH4排放通量随土壤温度的升高均呈指数式增长.其中,高水位下CH4排放通量对土壤温度变化最为敏感,中水位下次之,低水位下相对最不敏感.研究显示,若尔盖泥炭地CH4排放通量表现出明显的季节性变化差异,并且季节性升温和涨水均会促进CH4排放通量的增加.

[目的]研究秦岭中段油松天然次生林群落的物种多样性,为其生态系统管理、生物多样性保护以及生态功能优化提供理论依据.[方法]采用样方调查法,在陕西太白山和周至自然保护区,分别依据环境因子(海拔、坡向等)选取发育阶段一致的有代表性的油松典型群落类型,共建立20 m×30 m样地20个,记录乔木层、灌木层和草本层的物种数量,分析秦岭中段油松次生林群落各层次物种的重要值、物种多样性,以及环境因素对物种多样性的影响.[结果]秦岭中段油松天然次生林群落不同层次物种丰富度为灌木层＞草本层＞乔木层,灌木层物种多样性高,乔木层优势种明显;其中乔木层以优势种油松的重要值最高,而灌木和草本优势种重要值较低;灌木层和草本层的物种丰富度指数、多样性指数、优势度指数以及均匀度指数均随着海拔增高呈现先增后减的趋势,且基本呈正态分布;在坡向对物种多样性的影响中,除了均匀度指数外,其余各指数在阳坡相对较高,物种较为丰富;相对于草本,坡向对灌木层物种的影响更为明显.[结论]秦岭中段油松天然次生林群落物种较为丰富,多样性较高,海拔、坡向对群落物种多样性均有影响.

[目的]分析秦岭林区华山松天然次生林群落乔木层、灌木层、草本层各优势种群的种间关联性,揭示群落发育过程中不同种群之间相互作用的内在关联,以期阐明群落发展与演替和种对间关联性内在规律,为秦岭林区华山松群落可持续经营管理提供理论依据.[方法]选取秦岭山地火地塘林区典型华山松天然次生林群落,基于2×2列联表,采用方差比率法测定乔木层、灌木层和草本层各优势种群间的总体关联性;利用X2检验和Jaccard指数表征乔木层15个优势种群、灌木层19个优势种群、草本层15个优势种群间的种对关联程度及显著性.[结果]华山松天然次生林群落乔木层、灌木层和草本层优势种群间的总体关联性分别表现为不显著正关联、不显著负关联和显著正关联;x2检验结果显示该群落乔木层、灌木层和草本层均以正关联种对数占绝对优势,分别达81.9％,77.2％和85.7％,负关联种对数次之,分别为15.2％,13.5％和4.8％,无关联种对数较少,极显著和显著正关联种对数分别为11,2和5对,极显著和显著负关联种对数分别为13,2和1对;Jaccard指数结果与x2检验结果高度一致,该群落3个层次Jaccard指数较高的种对基本都表现为极显著和显著正相关;青榨槭和千金榆、青榨槭和刺叶栎、刺叶栎和少脉椴、山蚂蝗和刚毛忍冬、野草莓和牛尾蒿种对JI值＞0.6,二者之间存在一定的依赖关系,其余种对JI值较小.[结论]秦岭山地华山松天然次生林群落乔木层、灌木层、草本层各优势种对间种间关联明显,该群落总体结构为针阔混交林,物种之间存在一定的独立性,趋于形成一个整体较为稳定的群落.乔木层优势种群种间联结较松散,具有一定的独立性,但独立程度较低,基本趋于稳定,灌木层优势种群则处于动态演替的不稳定阶段,草本层优势种群结构较为稳定.综上所述,种间联结性分析可以作为探讨森林群落稳定性与演替过程中种间关系动态变化的有效途径,实践中应将正联结性较强的树种作为生态树种加以保护,以缩短秦岭山地华山松天然次生林演替的进程.

从云南文山三七药材基地感染根腐病的三七组织获得分离物,并对其进行培养和纯化,并运用科赫法则(Koch,s Postulate)进行病原菌回接感染,得3株致病明显的菌株,后对此菌株进行生物学和18S-rDNA全序列分析鉴定及室内药效防治.结果表明,此3株菌分别是尖孢镰刀菌(Fusarium oxysporum),茄病镰刀菌(Fusarium solani)和链格孢菌(Alternaria alternata).甲基硫菌灵、根康、多菌灵对茄孢镰孢菌、尖镰孢菌的抑菌效果最好,腐霉利、甲基硫菌灵对链格孢菌的抑菌效果最好.该研究可为尖孢镰刀菌、茄病镰刀菌和链格孢菌引起的三七根腐病的防治提供参考.

Heavy metal pollution is one of the most concerned water environmental problems. In this study, the effects of different Cd2+con-centrations on the growth, pigments, hydrogen peroxide, superoxide anion and soluble protein of Scenedesmus quadricauda were investigated in laboratory. Result showed that algal growth was inhibited under cadmium stress, especially under high cadmium concentrations(3~7 mg· L-1). Pigment(chlorophyll a, chlorophyll b, and carotenoids)contents decreased with increasing concentrations of cadmium. Contents of hy-drogen peroxide and superoxide anion increased significantly under 5~7 mg·L-1 and 7 mg·L-1, respectively. Soluble protein content reached the maximum at 1 mg·L-1 and decreased afterwards. Scenedesmus quadricauda displayed better tolerance to cadmium(upto 1 mg·L-1 cad-mium).

A large portion of the global carbon pool is stored in peatlands, which are sensitive to a changing environment conditions. The hydrological loss of dissolved organic carbon (DOC) is believed to play a key role in determining the carbon balance in peatlands. Zoige peatland, the largest peat store in China, is experiencing climatic warming and drying as well as experiencing severe artificial drainage. Using a fully crossed factorial design, we experimentally manipulated temperature and controlled the water tables in large mesocosms containing intact peat monoliths. Specifically, we determined the impact of warming and water table position on the hydrological loss of DOC, the exported amounts, concentrations and qualities of DOC, and the discharge volume in Zoige peatland. Our results revealed that of the water table position had a greater impact on DOC export than the warming treatment, which showed no interactive effects with the water table treatment. Both DOC concentration and discharge volume were significantly increased when water table drawdown, while only the DOC concentration was significantly promoted by warming treatment. Annual DOC export was increased by 69% and 102% when the water table, controlled at 0 cm, was experimentally lowered by -10 cm and -20 cm. Increases in colored and aromatic constituents of DOC (measured by Abs(254 nm), SUVA(254 nm), Abs(400 nm), and SUVA(400 nm)) were observed under the lower water tables and at the higher peat temperature. Our results provide an indication of the potential impacts of climatic change and anthropogenic drainage on the carbon cycle and/or water storage in a peatland and simultaneously imply the likelihood of potential damage to downstream ecosystems. Furthermore, our results highlight the need for local protection and sustainable development, as well as suggest that more research is required to better understand the impacts of climatic change and artificial disturbances on peatland degradation.

Plant composition and community structure of Tsugachinensiswere studied through sample plot.The result showed that Tsuga chinensis forest's age ranges from 20ato 200a,with most trees at60ato 90a.The forest trees,with an coverage of 90%together with grass coverage at 8%,average19.6min height,29.9cm in diameter.The stand density is 390plant per hectare,with most trees at22-26cm and26-30cm diameter,and 24-26m,26-28min height.There were 8tree species in tree layer with importance values from 0.02%to 97.91%.Tsuga chinensis is constructive species in the community.The were 15species in shrub layer and Fargesia qinlingensis is dominant species,with its importance value at 48.38%.There are 11species in herb layer and Viola yedoensis is dominant species with its importance value at 35.59%.

Buddleja Linnaeus (1753: 112) is a medium-sized genus within Scrophulariaceae comprising about 100 species, distributed in tropics and subtropics of America, Africa, and Asia, with 21 species and 5 hybrids known to occur in China (Li & Leeuwenberg 1996, Liu & Peng 2004, 2006).

报道了陕西省4种新记录植物,分别是总序香茶菜[Isodon racenosus (Hemsley)H.W.Li]、绵毛金腰[Chrysosplenium lanuginosum J.D.Hooker&Thomson.]、紫花娃儿藤(Tylophora henryi Warburg)、球果假沙晶兰[Monotropastrum humile (D.Don)H.Hara].对于补充完善陕西植物资源,研究秦岭植物区系有重要意义.凭证标本存于西北农林科技大学植物标本馆(WUK).