梅花根际土壤栽培三叶草的丛枝菌根侵染研究

从北京、武汉、南京、重庆、昆明五个梅园和野梅主要分布区的云南嵩明、四川木里、贵州茂兰自然保护区,以及北京林业大学的梅圃中分别于春、夏、秋、冬四季,采集梅花根际土壤300份。以梅花根际土壤和蛭石体积为1∶1混合作为栽培基质,种植三叶草,培养4个月后,应用染色镜检法测定丛枝菌根真菌(AMF)侵染三叶草根系的状况。结果表明:所有梅花根际土壤栽培三叶草都有丛枝菌根侵染;野生梅花根际土壤栽培三叶草的丛枝菌根侵染率高于人工梅园;四季的梅花根际土壤栽培三叶草丛枝菌根侵染在季节间无明显差异。     

梅花花粉量及离体萌发特性研究

对44个梅花品种的花粉量和41个品种的花粉离体萌发率进行了测定,并比较了不同萌发培养液、不同采粉时期等因素对花粉萌发率的影响。结果表明:(1)梅花品种间单花药花粉量有很大差异,变化值0~11 083(。2)不同离体萌发培养液对花粉萌发有较大影响,多数品种的适宜培养液为10%蔗糖 0.01%硼酸。(3)品种间花粉萌发率存在很大差异,最高85.14%,最低为0.11%。(4)25℃,花粉于液体培养基30 min后开始萌发,6 h后花粉管达最长。(5)初花期和盛花期的花粉萌发率差异不显著,花粉萌发率与花粉饱满度和花粉量具有一定正相关性。     

摘心对欧李实生苗生长与成花的影响

为探明摘心对欧李实生苗生长与成花的影响,以当年播种、移植的欧李实生苗为研究对象,分别于苗高20、30、40cm时进行摘心.试验结果表明:欧李实生苗主干摘心能有效地促发二次枝,由于二次枝的产生,极显著地增加了株丛的新梢数量和叶片数量,从而达到了促进欧李实生苗基部的加粗生长、扩大冠幅和当年成花的目的.从3个处理高度的效果来看,以苗高30cm时摘心效果最佳,其二次枝数量、叶片数量、冠幅、苗木基部粗度及花芽分化数量均显著地优于苗高20cm、40cm时的摘心效果.但不同的摘心高度对欧李实生苗的树体高度及叶片的叶绿素含量均未形成显著的影响.     

朝阳地区山杏花期及结实率影响因子的初步研究

山杏是辽宁朝阳地区主要的经济林树种,但结实率低。为解决这一问题,选取不同坡向、坡位(东北坡、东坡下腹、北坡、东坡上腹和南坡)的山杏林分,调查开花物候期和坐果率,研究不同气象因子对山杏坐果率的影响。结果表明:阳坡开花期最早,半阴坡略延迟,阴坡最晚。受温度、光照、相对湿度及风速影响,不同坡向的坐果率差异较大,即东北坡东坡下腹北坡东坡上腹南坡,同一坡向(东坡)的下腹要高于上腹。     

大岛樱病虫害及其防治的研究

本文对大岛樱中国引种点危害较严重的４种病害和２种害虫进行观测和种类鉴定，指出了各病虫害的危害症状和发生发展规律等，并试验或介绍了相应的防治措施。     

Seasonal dependence of rooting success in cuttings from natural forest trees in Madagascar

Four ligneous species from the tropical forest in the east of Madagascar, with a proven or potentially high economic value, were subject to ‘low-tech’ vegetative propagation tests from stem cuttings. The species concerned were Aphloia theiformis, Ilex mitis, Prunus africana and Ravensara aromatica. The cuttings were three-node segments of stems on which one leaf was retained. All the species proved amenable to rooting. The maximum percentage of rooting ranged from 33% for P. africana to 60% for I. mitis. Rooting success was dependant on the season of cutting (high in the hot season, from October to May, and null in cold season). This study is the first successful attempt at propagating cuttings from Malagasy forest species. This result is of particular importance to P. africana, threatened by destructive exploitation in Madagascar. It goes a step further in the domestication of this species by demonstrating the ability of cutting from 10 year old ortets collected in natural forest to root as it offers the possibility of a reliable and effective method of reintroduction for the species in overexploited zones.     

紫叶桃（Prunus persica f．atropurpurea）的愈伤组织诱导和培养

紫叶桃是重要的园林彩叶树种,叶色美丽,观赏期长,具有很高的园林应用价值。以紫叶桃的叶片和嫩茎段为外植体,用不同浓度生长调节物质进行愈伤组织诱导试验,建立紫叶桃的再生体系。结果表明,诱导愈伤组织时,MS＋2mg／LBA＋1mg／L2,4-D对叶片诱导效果最佳,其诱导率达80％;MS＋1mg／LBA＋1mg／L2,4-D对茎段诱导效果最佳,其诱导率达100％。在MS＋1mg／LBA＋1mg／L NAA培养基上愈伤组织能直接分化出不定芽。     

Influence of different forest conversion strategies on ground vegetation and tree regeneration in pine (<Emphasis Type="Italic">Pinus sylvestris</Emphasis> L.) stands: a case study in NE Germany

The conversion of anthropogenic into more natural, self-regenerating forests is one of the major objectives of forestry throughout Europe. In this study, we present investigations on permanent plots with different silvicultural treatment in NE German pine stands. Management of old-growth pine stands on acidic and nutrient-poor sandy sites differs in fencing, thinning, and planting of certain tree species. The investigations were carried out on the community, population, and individual level of the pine forest ecosystems. Thus, vegetation changes, size and height of tree populations, and height increment of tree individuals were observed over a time span of 6 years. Special attention was paid to short-lived tree species such as, e.g., Frangula alnus and Sorbus aucuparia, as well as to Fagus sylvatica as one of the most typical forest tree species of Central Europe. Vegetation changes are interpreted as a consequence of natural regeneration of formerly degraded forest sites, involving an increase in nutrient availability. High browsing pressure can be considered as a key factor for the inhibition of tree seedlings and growth of saplings. Some Sorbus aucuparia individuals, however, succeeded in growing out of the browsing height also in unfenced stands. Few found specimens of Fagus sylvatica proved that this species is able to establish spontaneously on these relatively dry, acidic sites under continental climate influence. Such natural regeneration processes, also including spontaneous rejuvenation of trees, can be integrated into silviculture as passive forest conversion management. An active management like thinning of stands, planting of trees, and fencing can accelerate forest conversion with regard to height growth and species number of trees.     

青梅抗黑星病无性系抗病适应性研究

在果期不施用农药的条件下,对青梅抗黑星病无性系的鲜果抗黑星病能力进行测定试验,结果表明:①青梅在不同的产区,抗黑星病无性系都具有极显著的抗黑星病能力,初步选育的抗病无性系在不同产区抗病性能无显著差异;②不同无性系中,抗黑星病无性系鲜果病斑症状出现的时间比普通龙眼梅显著推迟;③抗黑星病无性系有较强的抗落果性能。     

榆叶梅等3种园林灌木的蒸腾特性

在利用LI-6400便携式光合系统测定分析阿克苏市3种园林灌木榆叶梅、红瑞木、紫穗槐蒸腾速率日变化、月变化特征的基础上,研究了光照强度、大气温度、大气相对湿度、大气水势、气孔导度、叶温下蒸汽压亏缺对蒸腾速率的影响,并进行相关性分析,建立了逐步回归模型。结果表明:3种灌木的蒸腾速率日变化均呈早晚低、中午高的单峰曲线,3种灌木蒸腾速率的大小为榆叶梅>红瑞木>紫穗槐,这与自由水含量的高低顺序一致。蒸腾速率的月变化为7月最高,5月和9月较低。水分利用效率的日变化曲线表现为早晨低、中午高、下午降低、傍晚又升高的特点,在生长季节,月变化为5月份最高,7月份最低。在影响蒸腾速率的各因子中,与之相关性最大的为光照强度,相关系数达到0.960,进行逐步回归分析后,3个模型都只含有光照强度一个因子。