Effect of some chemicals employed in the detached leaf culture of Populus on the infection of Melampsora larici-populina

A study was made on the effect of certain chemicals and their combinations on the longevity of the leaf disks cut from Populus × euramericana‘1-488’and P. alba cv. hickeliana. Benzimidazole and gibberellic acid maintained (up to a maximum of 80 days) the leaf disks better than the others, however, the longevity was dependent on the chemical and the concentration employed. In a factorial experiment of 3 chemicals × 2 concentrations × 2 cultivars × 2 races of the fungus, it was found that. all these factors contributed significantly (P<0.05) to the experimental variance. However, differential effects of the chemicals or the concentrations on the cultivar × race interaction were not observed.     

两种杨树树皮内生真菌多样性及优势种群动态变化

为了解健杨94(转基因抗虫杨94)、三倍体毛白杨2个杨树品种干部树皮内生真菌区系及其优势种群的季节变化情况,本研究利用组织分离法从2个杨树品种996块组织中分离内生真菌1 175株,健杨94和三倍体毛白杨分别分离612、563株.利用形态特征和分子生物学方法鉴定为15个属、35个分类单元,包括担子菌1个分类单元,子囊菌34个分类单元.2个杨树品种内生真菌优势种群包括链格孢、葡萄座腔菌、镰孢属真菌、间座壳属真菌等,其中,仅有链格孢、葡萄座腔菌和桑砖红镰孢是两品种共有的优势种群种类,而且优势种群会随季节变化而变化.在两品种的内生真菌中,链格孢、葡萄座腔菌是最为常见的优势种群.     

Susceptibility of Ribes spp. to pine stem rusts in Finland

Susceptibility of Ribes spp. to three pine stem rusts, Cronartium ribicola, Cronartium flaccidum and Peridermium pini, was investigated by inoculations both in laboratory and in greenhouse conditions, and by observing sporulation on Ribes spp. leaves under natural and artificial inoculum in 16 experiments. Twenty‐seven Ribes spp. cultivars were inoculated in 2000–2004 using 41 sources of C. ribicola aeciospores from a wide geographic range, and six Pinus spp.; 51 sources of C. flaccidum and 11 sources of P. pini from Pinus sylvestris. The results were very similar both after artificial inoculations and observations under natural inoculum in repeated experiments over the years. Cronartium ribicola uredinia and telia developed frequently or moderately on nine Ribes nigrum cultivars but were not present on two cultivars. Sporulation developed on five Ribes rubrum cultivars but was absent on two cultivars. Three Ribes uva‐crispa cultivars were only weakly susceptible to C. ribicola, while all R. alpinum cultivars were resistant to the rust. The other Ribes spp. tested, Ribes niveum, Ribes aureum, Ribes odoratum, Ribes sp. × nigrolaria, Ribes glandulosum and Ribes × culverwellii Jostaberry, were all susceptible to C. ribicola. Cultivars of R. nigrum were more susceptible than those of any other species. No significant variation in virulence of the aeciospores was observed between and among Ribes hosts over the years. Cronartium flaccidum and Peridermium pini did not form any uredinia or telia on Ribes spp. in any of the experiments.     

Sensitivity to pre- and post-inoculation temperature of the reactions of Populus spp. to Melampsora medusae thüm

Replicate clones of compatible cultivars of Populus deltoides and P. euramericana, grown for 3 months on a high (28/20°C - day/night) temperature regime and incubated, following inoculation with a mixture of urediniospores of six races of Melampsora medusae, on a high (28/20°C - light/dark) temperature regime, were more resistant (as determined by uredinial number) to leaf rust than those raised and incubated on any other combination of the high (28/20°C) and low (20/10°C) pre- and post-inoculation temperature regimes. Irrespective of the parameter employed to assess disease intensity, cultivar constitution and pre- and post-inoculation temperature are significant contributors to the level of disease induced in the cultivars by the isolate of M. medusae. The rating of cultivars for relative resistance is somewhat dependant on the parameter employed to assess disease, and for most parameters there are significant interactions of cultivar and pre- and post-inoculation temperature in determining the disease level induced. The coefficients of determination between the parameters of disease level are low, hence the results of the experiment are of limited value for extrapolation to field conditions. The possibility, in future investigations, of employing a disease parameter with more epidemiological significance is discussed.     

Growth and morphology of three forest understorey species (Calluna vulgaris, Molinia caerulea and Pteridium aquilinum) according to light availability

Calluna vulgaris, Molinia caerulea and Pteridium aquilinum are three forest understorey species that compete with tree seedlings for environmental resources. Forest managers therefore seek to control their growth, which is driven in part by the light available in the forest understorey.An experiment was set up in a nursery in which the three understorey species C. vulgaris, M. caerulea and P. aquilinum were planted at six light levels (6, 11, 22, 36, 48 and 100% of full sunlight) replicated in three blocks. The different light levels other than 100% were obtained using neutral shading nets. The response of the three species to light availability was estimated after two growing seasons by their cover and height, their morphology, assessed by the foliar tuft height-to-width ratio for C. vulgaris and M. caerulea and by the frond height-to-length ratio for P. aquilinum, and their functional acclimation, assessed by a leaf trait (leaf mass on an area basis, LMA).Vegetation cover changed with light availability following a bell-shaped curve. By contrast, vegetation height remained approximately the same, irrespective of the light treatment, except for P. aquilinum, which grew higher than the other two species at medium and high light levels. As a consequence, vegetation individuals were more spindly in a dark environment. From the lowest light treatment, P. aquilinum cover was high (75%) and intercepted a larger proportion of the light than the other two species. This species thus proved the most competitive for light.All three species showed a notable acclimation to light availability by their LMA, though in different ways. The LMA of C. vulgaris decreased in shaded conditions by an increase in leaf area, whereas decrease in LMA for P. aquilinum was due to a decrease in leaf mass. For M. caerulea, the LMA remained stable whatever the light conditions by a simultaneous increase in both leaf mass and leaf area in shaded conditions.Consequently, the in-forest development of C. vulgaris and M. caerulea could be managed through small adult canopy thinnings, as both species grew well from light levels above 20%. Conversely, it seems unrealistic to manage P. aquilinum in this way as its development was almost maximal even at very low light levels.     

白刺枝叶生长对人工模拟降雨的响应

为揭示未来降水增加对荒漠地区植物生长的影响,以甘肃民勤的典型荒漠优势植物白刺为对象,研究白刺枝叶形态在2010年和2011年不同人工模拟降雨处理(增雨量分别为多年平均降水量的+0%、+25%、+50%、+75%、+100%)的变化规律。结果表明:100%增雨处理能够显著促进2010年和2011年白刺当年生枝叶生长;75%增雨处理显著促进2011年白刺当年生枝叶生长,75%增雨处理对6月花枝长度、基部直径、新生叶片和营养枝长度、新生叶片,以及9月花枝成熟叶片和营养枝基部直径、成熟叶片增长量的影响均显著,其值分别为(1.20±0.35)cm、(0.012±0.004)cm、(4.35±2.51)片、(1.65±0.69)cm、(3.20±1.45)片、(2.15±0.69)片、(0.013±0.006)cm、(2.20±1.10)片。2011年白刺当年生花枝和营养枝的长度、基部直径、新生叶片和成熟叶片增长量出现显著差异的阈值均低于2010年,这表明白刺能够通过改变其枝叶形态特性及其数量来适应降雨的变化。     

Ecology of some fungi associated with an ageing stand of birches (Betula pendula and B. pubescens)

When stydying the growth of different provenances of Betula pendula and B. pubescens it was noted that fruitbody production by many sheathing (ecto-)mycorrhizal fungi followed distinctive patterns in time and place.When saplings of B. pendula and B. pubescens, from seed collected from ranges of locations in western Europe, were grown on a brown earth at latitude 55° 52′ N, autumnal yellowing and defoliation occurred sooner on saplings originating from northern locations (Scandinavia, 60°–66°N) than on those from the south (United Kingdom and Germany, 50°–55°N); the latter group of trees, particularly of B. pubescens, tended to be taller than the former.In the first 6 years after planting Betula spp., more than 90% of the fruitbodies (toadstools, earth-fans of Thelephora terrestris and elf-cups of Peziza badia), usually appearing in the autumn, were of fungi known, or suspected, to form sheathing mycorrhizas with Betula spp. Mean numbers of fruitbodies increased from 0.4 to 28 and 170 per tree in the 2nd, 4th and 6th years respectively after planting. Numbers of fungal species producing fruitbodies progressively increased from one, Hebeloma crustulvniforme, in the 2nd year to 14 (B. pubescens) and 18 (B. pendula) in the 6th year when Hebeloma spp. accounted for 79% of fruitbodies; Laccaria ‘laccata’, 15%; Inocybe lanuginella, 5% and Lactarius pubescens, 1%. Of the 6th year Hebeloma total, H. crustuliniforme, H. fragilipes, H. mesophaeum and H. sacchariolens accounted for 32, 33, 13 and 11% repectively.Mean distances between fruitbodies and the stems of trees widened at c. 0.16 m year^?1 for Hebeloma crustuliniforme; for Laccaria ‘laccata’ they increased by 0.27 to 0.87 m year^?1 between the 4th and 5th years after planting but remained virtually unchanged in the 6th year. Distributions differed within and between concentric 10 cm annuli. In the 6th year appreciably more Hebeloma fruitbodies, except those of H. sacchariolens, were found in intermediate annuli than in annuli nearest and furthest from trees. In contrast those of Laccaria ‘laccata’ and Inocybe lanuginella developed at densities of 1500 m^?2 and 500 m^?2 in most annuli.Fruitbodies of Laccaria ‘laccata’ were significantly clustered in sectors of the differing annuli possibly reflecting associations with radially growing secondarily thickened roots, whereas those of I. lanuginella occurred at random.From 2 to 6 years after planting the mean annual production of toadstools and elf-cups averaged 55 and 0.1 per tree originating from latitude 50° N and 66° N respectively. Earth fans of Thelephora terrestris were likewise less commonly associated with trees of northern origin.B. pubescens, unlike many provenances of B. pendula, seemed to resist invasion by the leaf rust Melampsoridium betulinum. The northern provenances of B. pendula were significantly more seriously infected than southern provenances.     

金合欢属植物组织培养研究进展

金合欢属植物生长速度快、产量高、材质好、适应性强、用途广,在我国南方林业生产中占据重要地位。掌握该属植物的组织培养技术,对促进其产业发展具有重大意义。文中从外植体、基本培养基、培养条件、植物生长调节剂、组培苗移栽等方面简述20世纪80年代以来金合欢属植物组织培养技术的研究进展,并就组培快繁中存在的主要问题提出相应的解决方法,同时提出今后的研究展望,以期为建立金合欢属植物高效组培体系及工厂化育苗提供参考。     

Photosynthetic characteristics of Fagus sylvatica and Quercus robur established for stand conversion from Picea abies

Efforts in Europe to convert Norway spruce (Picea abies) plantations to broadleaf or mixed broadleaf-conifer forests could be bolstered by an increased understanding of how artificial regeneration acclimates and functions under a range of Norway spruce stand conditions. We studied foliage characteristics and leaf-level photosynthesis on 7-year-old European beech (Fagus sylvatica) and pedunculate oak (Quercus robur) regeneration established in open patches and shelterwoods of a partially harvested Norway spruce plantation in southwestern Sweden. Both species exhibited morphological plasticity at the leaf level by developing leaf blades in patches with an average mass per unit area (LMA) 54% greater than of those in shelterwoods, and at the plant level by maintaining a leaf area ratio (LAR) in shelterwoods that was 78% greater than in patches. However, we observed interspecific differences in photosynthetic capacity relative to spruce canopy openness. Photosynthetic capacity (A₁₆₀₀, net photosynthesis at a photosynthetic photon flux density of 1600 μmol photons m⁻² s⁻¹) of beech in respect to the canopy gradient was best related to leaf mass, and declined substantially with increasing canopy openness primarily because leaf nitrogen (N) in this species decreased about 0.9 mg g⁻¹ with each 10% rise in canopy openness. In contrast, A₁₆₀₀ of oak showed a weak response to mass-based N, and furthermore the percentage of N remained constant in oak leaf tissues across the canopy gradient. Therefore, oak photosynthetic capacity along the canopy gradient was best related to leaf area, and increased as the spruce canopy thinned primarily because LMA rose 8.6 g m⁻² for each 10% increase in canopy openness. These findings support the premise that spruce stand structure regulates photosynthetic capacity of beech through processes that determine N status of this species; leaf N (mass basis) was greatest under relatively closed spruce canopies where leaves apparently acclimate by enhancing light harvesting mechanisms. Spruce stand structure regulates photosynthetic capacity of oak through processes that control LMA; LMA was greatest under open spruce canopies of high light availability where leaves apparently acclimate by enhancing CO₂ fixation mechanisms.     

Temperature sensitivity of qualitative race-cultivar interactions in Melampsora medusae Thüm. and Populus species

Six mono-uredospore isolates (races) of Melampsora medusae Thiim. produced qualitatively distinct reactions, in vitro, when incubated at 15 °C on leaf disks of certain cultivars of Populus deltoides Marsh. The infection types in some race-cultivar combinations were very temperature sensitive with less distinct reactions when incubated at 20 or 25°C. The significance of differential race-cultivar-temperature interaction in the epidemiology of M. medusae is discussed.     

Susceptibility of Pedicularis spp. to Cronartium ribicola and C. flaccidum in Finland

Aeciospores of Cronartium ribicola and C. flaccidum were collected from several locations in Finland and used to inoculate Pedicularis spp. and some known and suspected alternate hosts in 2008–2009. In all trials, C. ribicola formed uredinia and telia on leaves of Ribes nigrum. No uredinia or telia of C. ribicola formed on older leaves of Pedicularis spp. but both uredinia and telia were found on young leaves of P. palustris ssp. palustris. Cronartium flaccidum produced uredinia and/or telia on leaves of P. palustris ssp. palustris, P. lapponica, Vincetoxicum hirundinaria and Melampyrum sylvaticum. Neither rust infected P. sceptrum‐carolinum, Vaccinium myrtillus, Calluna vulgaris or Ledum palustre. Similar to rusts in Asia and North America, the results showed that European C. ribicola exhibit more variable host reactions and wider alternate host ranges than earlier described. Pedicularis palustris may play a role in the spread of Cronartium in natural forests.     

Short-term effects of hexazinone applications on woody species diversity in young loblolly pine (Pinus taeda) plantations

Data from four studies determining the susceptibility of woody plant species to foliar applications of several rates of liquid hexazinone (Velpar L®) were used to examine the short-term effects of the herbicide on woody species diversity in young loblolly pine plantations. Woody species diversity, as measured by four similarity measures between pretreatment and post-treatment species importance or diversity, decreased significantly with increasing hexazinone rate. Woody species shown to be among the most susceptible (sumacs (Rhus spp.) and oaks (Quercus spp.)), and least susceptible (loblolly and other pines, and Vaccinium spp.) to hexazinone in previous herbicide screening trials decreased and increased in importance, respectively. Differences in similarity measures between the no-hexazinone treatment and the 1.0 × hexazinone rate (1.2 to 1.5 kg a.i./ha depending on the study location) 2 years after herbicide application were small.     

杜鹃红山茶CaAPX基因的克隆、表达及功能分析

[目的]利用分子生物学技术探讨杜鹃红山茶CaAPX基因的表达模式及在模式植物烟草中所起的抗寒、耐热作用,为今后山茶花抗逆育种奠定基础。[方法]根据山茶花同源序列设计特异性引物,利用同源克隆和3’,5’-RACE技术,从杜鹃红山茶嫩叶组织中克隆出抗坏血酸过氧化物酶(APX),命名为CaAPX,基因全长1 097 bp,开放阅读框753 bp,编码250个氨基酸。实时荧光定量PCR对杜鹃红山茶7种组织和温度胁迫下该基因的表达模式进行分析。[结果]表明:CaAPX基因在杜鹃红山茶7种组织中均得到表达,但表达水平不一,表达量由高到低依次为:未成熟果实嫩叶花苞叶芽种胚花瓣花芽,其中,未成熟果实中的表达量是其它组织的2.6811.44倍;温度胁迫处理8 h后该基因呈上调表达,CaAPX基因表达量分别是0 h的3.49和2.67倍。CaAPX基因转化烟草分析表明,过量表达CaAPX基因后,APX活性提高了2.58 4.09倍,抗坏血酸(As A)含量提高了2.673.56倍,并且转基因烟草植株的抗寒、耐热能力也获得提高。[结论]通过过量表达CaAPX基因能够提高烟草植株的抗寒、耐热性,为山茶花抗逆育种提供了科学依据。     

南北样带温带区栎属树种幼苗功能性状的变异研究

植物功能性状由生境条件和遗传因素共同决定,田间控制实验能够揭示植物功能性状在种内和种间的变异程度.采集南北样带温带区8个地点6种栎属树种的种子,通过田间栽培试验,以均一环境下1年生幼苗为对象,研究比较种内及种间比叶重、单位叶面积光合速率、单位叶重量光合速率、总干物质含量和根冠比5种功能性状的变化差异,并且分析幼苗功能性状与种子性状的关系.结果发现:栎属树种种间幼苗的功能性状变异系数高于种内,并且种内功能性状的差异较小,种间差异性较大,而比叶重和叶片光合速率无论在种间还是种内,其变异率都较小;总干物质量和根冠比与种子质量显著相关,随种子质量增加幼苗的总干物质量和根冠比呈现增加的趋势,比叶重和叶片光合速率与种子质量的相关性较小.     

马尾松钙调素基因的克隆及响应松材线虫侵染的表达特征

松材线虫病是由松材线虫(Bursaphelenchus xylophilus)侵染引起的严重病害,引起重大的经济和生态损失。钙调素(CaM)是真核生物中Ca2+主要传导蛋白,本研究采用RT-PCR方法,首次从马尾松中克隆获得CaM,命名为pmCaM,并检测了其响应松材线虫侵染的表达特征。序列分析表明:pmCaM完整的开放阅读框核苷酸序列为450bp,编码149个氨基酸的蛋白质;该蛋白含有4个EF-hand结构域,具有钙调素的典型特征,与其它植物的CaM蛋白均有较高同源性。实时荧光定量PCR分析显示:接种松材线虫后30 180 min时间段,马尾松苗根、茎、叶器官中的pmCaM均下调表达,但不同器官间显著下调表达的时间点存在差异;同时,不同器官pmCaM表达量变化均存在特异的随时间发展的波动特征,其中发现,根茎pmCaM在松材线虫接种45 min时均处于表达量高峰。本研究结果显示pmCaM表达响应了松材线虫侵染,揭示pmCaM可能参与了调控松材线虫-马尾松互作早期的钙信号响应。     

朱顶红属植物种质资源及园林应用

朱顶红属植物花朵大而美丽,叶片荧绿如带,既可用作室内花卉装饰,又可应用于室外的园林造景。该属植物在国外很受欢迎,具有很高的观赏价值和经济价值,而在我国还没有广泛研究和应用。文中概述朱顶红属植物的种质资源和育种研究情况,分析总结其在园林应用中的形式,提出并讨论其在我国推广发展的可行性。     

濒危植物篦子三尖杉的群落特征

研究了云南、贵州和江西自然分布的8个篦子三尖杉群落。群落共有微管属植物108科,235属,336种。篦子三尖杉在群落中是主要层的共优种或伴生种,但随着生境条件不一致,这些篦子三尖杉生长地的植物群落类型也各不相同。群落组成上以樟科和蔷薇科等为主要优势科,山胡椒属和荚蒾属等属为主要优势属,伊桐、灯台树、木姜子、八角枫、短梗大参、大叶方竹、毛竹等是主要优势种;群落外貌特征同亚热带常绿阔叶林近似,生活型组成以高位芽植物为主, 高位芽植物(Ph.)、地上芽植物(Ch.)、地面芽植物(H.)、隐芽植物(Cr.)和一年生植物(Th.)分别占62.78%、12.67%、9.73%、12.29%和2.53%。叶级以微型叶为主(68.49%),无大型叶和巨型叶。叶质以纸质叶所占比例最大(55.89%),膜质叶最小(4.93%)。叶型以单叶为主(76.99%),全缘叶和非全缘叶近相等;从群落结构上看,8个群落的乔灌木个体在水平空间均呈集群分布状态,而群落以高于3.5 m以上的层次在群落中占优势, 平均盖度为68.71%。从目前的静态生命表看,道真县、江口县、台江县、镇远县的篦子三尖杉种群属于增长型种群,而芦溪县、凯里市、屏边县和新平县的种群属于稳定型种群;此外,不同群落之间具有物种多样性水平明显不同,群落之间的共有种少,相似程度较低等特点。     

麻竹枝叶生长对钩梢的响应

为了解冠层生物量积累、分配及枝叶大小对麻竹立竹受营林措施干扰(钩梢)后的响应,对不同竹龄全梢、钩梢麻竹地上构件生物量、生物量比、单叶特征、大小枝生物量分配比例及商品竹叶数量进行了调查.结果表明:麻竹立竹地上现存生物量分配格局为秆＞枝＞叶.叶生物量、叶/枝和叶/秆生物量比为2年生＞3年生＞1年生.随着竹龄的增加,枝、秆生物量、地上生物量和枝/秆生物量比总体上呈增加的趋势.2年生和3年生立竹枝、叶生物量分配比例显著高于1年生立竹,秆生物量分配比例显著小于1年生立竹.此外,随着竹龄的增加,立竹减少了对0 ～8 mm枝生物量的分配,增加了对8～16 mm、16 mm以上枝生物量的投入,以提高空间拓展能力,截获更多光资源.钩梢强烈影响了生物量分配格局,显著减小了麻竹立竹枝、叶、秆、地上生物量.钩梢后麻竹立竹增加了枝、叶生物量分配比例,减少了秆生物量的分配比例,同时提高了单叶叶面积和单叶干质量,增加了8～16 mm、16 mm以上枝生物量分配比例,减小0～8 mm枝生物量分配比例,以权衡枝叶的生长,提高立竹对环境的适合度.钩梢后立竹叶/枝、叶/秆、枝/秆生物量比升高,表明生物量分配更多地向叶和枝倾斜.钩梢麻竹商品竹叶数量较全梢麻竹增加29.68％,且发生部位明显降低,钩梢后冠层下部商品竹叶数量增加79.73％,中部商品竹叶数量增加25.81％,降低了采摘高度.在钩梢后的一个生长季内,钩梢影响了麻竹立竹资源利用策略,表现为枝与叶之间关系的变化,但随钩梢年限的增加其变化规律如何尚需进一步研究.     

Seedling growth and water relations of three Cedrela species sourced from five provenances: response to simulated rainfall reductions

The effects of different simulated rainfall regimes on water relations, growth, and biomass production and allocation of five provenances of Cedrela fissilis, C. saltensis and C. balansae were assessed in a pot-grown seedling experiment in greenhouse under uncontrolled conditions. Four simulated rainfall regimes were applied: 600 mm year^?1 (severe water deficit), 800 mm year^?1 (mild water deficit), 1,000 mm year^?1 (mild wet), and 1,200 mm year^?1 (well-watered) used as control. Provenances were compared in terms of water relations (midday leaf water potential, Ψ _md and relative water content, RWC), growth (root, shoot and leaf length, neck diameter), growth rate (shoot- and neck growth rate, SGR and NGR), biomass production (root, shoot and leaf dry weight), and biomass allocation (root:shoot ratio, RSR). Multivariate analyses revealed that water relations differed significantly under all simulated rainfall treatments by means of several variables throughout time. Effects of species × treatment, and provenance nested within species × treatment interactions significantly were important. SGR and RSR also were important to explain differences in Ψ _md and RWC between treatments and provenances. Broadly C. balansae and C. saltensis provenances seem to display a better performance than C. fissilis provenances under severe water deficit only. However, despite differences between provenances, it was not possible to clearly separate them according to their origin, based on water relations and growth performance. Even though the results of this study performed on pot-grown seedlings are based on relatively few observations and require additional confirmation, they allow an opportunity for speculation on the factors that are related to intraspecific variations that are likely to occur during the growth of seedlings from different geographical sites in field condition.     

Physiologic specialisation in the hyperparasitism of races of Melampsora larici-populina by isolates of Cladosporium tenuissimum

Three isolates of Cladosporium tenuissimum were prepared by culturing a field isolate of this organism separately on three races of Melampsora larici-populina. In a subsequent experiment, the production of uredinia by these three races on three cultivars of Populus X euramericana was usually lowest in the presence of the isolate of C. tenuissimum which had been cultured on the particular race. This apparent adaptation of the isolates of the hyperparasite to particular races of the rust, i. et. “physiologic specialisation” in the relationship, is confirmed by the significant race x C. tenuissimum isolate term in the ANOVA.