狮子关库区植物群落乔木层优势种及群落分类

对狮子关库区植物群落乔木层优势种及群落分类进行了研究，结果显示：库区乔木层优势种19种，包括常绿阔叶树7种、落叶阔叶树10种、针叶树2种。据此，库区有5个植被型17个群系34个群丛。     

临时样地中空间信息的提取

通过对日本落叶松临时祥地中优势木高生长与龄组关系的研究,综合不同林分中空间因子对林木生长的影响,从而提取出日本落叶松林中的空间信息：海拔、坡向、坡度、林分密度、土层厚度、坡位的分布情况。     

Fungal diversity on fallen leaves of Ficus in northern Thailand

Fallen leaves of Ficus altissima, F. virens, F. benjamina, F. fistulosa and F. semicordata, were collected in Chiang Mai Province in northern Thailand and examined for fungi. Eighty taxa were identified, comprising 56 anamorphic taxa, 23 ascomycetes and l basidiomycete. Common fungal species occurring on five host species with high frequency of occurrence were Beltraniella nilgirica, Lasiodiplodia theobromae, Ophioceras leptosporum, Periconia byssoides and Septonema harknessi. Colletotrichum and Stachybotrys were also common genera. The leaves of different Ficus species supported diverse fungal taxa, and the fungal assemblages on the different hosts showed varying overlap. The fungal diversity of saprobes at the host species level is discussed.     

贺兰山的灰榆林与灰榆疏林草原——以贺兰山东坡为例

本文从植物区系、群落的结构和动态、生境、在山地植被垂直带系列中的位序以及改造利用等方面论述了贺兰山灰榆疏林草原的主要特征,从而认为过去所称大面积的“灰榆疏林”除在个别地点分布的属于落叶阔叶林外,绝大部分应是一类由草原植物与散生小乔木结合形成的温带山地稀树草原,但它不同于热带稀树草原,故称为疏林草原。在贺兰山灰榆疏林草原是一类独特的原生植被类型,占据着一个独立的植被垂直带。     

Diversity of arbuscular mycorrhizal fungi associated with desert ephemerals growing under and beyond the canopies of Tamarisk shrubs

The arbuscular mycorrhizal （AM） fungal status of the four most common ephemeral plant species, Chorispora tenella （Pall.） DC., Ceratocephalus testiculatus （Crantz） Bess., Eremopyrum orientale （L.） Jaub et. Spash and Veronica campyIopoda Boiss growing in an area dominated by Tamarisk shrubs （Tamarix spp.） was investigated. Samples of the four ephemerals and their rhizosphere soils were collected from underneath and beyond the canopies of the Tamarisk shrubs. Plant mycorrhizal status and soil AM fungal spore densities and community structures were analyzed and compared under and beyond the shrub canopies. The mycorrhizal colonization rates of the ephemerals and spore densities in their corresponding rhizosphere soils were significantly lower under the shrub canopies than beyond. The number of AM fungal species under the shrubs （12） was also lower than beyond the canopies （19）. When soil properties in the rhizospheres of the four ephemerals were examined, available N and P and total P, organic matter content, total salt content and electrical conductivity （EC） were all higher under the canopies than beyond. In contrast, soil available K and pH showed no such trend. A total of 21 AM fungal species were isolated from rhizosphere soils of the four ephemerals. Five belonged to Acaulospora, one to Archaeospora, thirteen to Glomus and two to Paraglomus. We conclude that the canopies of Tamarix spp. exerted some influence on the AM status of the ephemerals and on the AM fungal communities and some of the properties of their rhizosphere soils.     

灵空山自然保护区油松辽东栎林灌木层物种组成及空间格局分析

基于灵空山油松-辽东栎林4hm2样地内400个10m×10m样方的调查数据,分析了林下灌木物种组成及分布格局。结果表明:林下的灌木有37种,隶属于11科23属,共记录个体数5 857株,70%物种的个体数在1-50之间;其中黄刺梅的个体数最多,占总个体数的32.64%;种的重要值为0.03~28.48,黄刺玫、金花忍冬和土庄绣线菊的重要值分别为28.48、22.40、14.67.采用方差/均值法对黄刺玫、金花忍冬、土庄绣线菊、牛奶子、小叶鼠李和毛榛的分布格局进行分析,由分析结果知均为集群分布;用负二项参数(K)、丛生指标(I)、扩散指数(C)和Cassic(CA)指标测定它们的集聚强度,结果证实了均为集群分布。     

沙漠勇士——骆驼刺

<正>在疏勒河下游的绿洲至库姆塔格沙漠和罗布泊的广大湖盆平原上,在海拔约700~1200米之间的区域内,凡是有绿色植被生长的地区,都有骆驼刺的身影。骆驼刺是沙漠地区一种常见且极其普通的灌草,虽默默无闻,却是在沙漠戈壁最前沿抵御风沙蔓延的勇士。骆驼刺(Alhagi sparsifolia),俗名青刺,是我国西北至中亚荒漠地区自然生长的耐旱耐盐碱植物。属豆科、落叶半灌木,枝上多刺,叶长圆形;6~8月开花,花色粉红,每朵花可开放20余天,小而美丽;结荚果,总状花序;植株从地下深层吸取水分和营养,其根系长可达20米,靠种子和根蘖繁殖。     

预处理方法对城市落叶生物降解影响的研究

以城市落叶为原料,经试剂预处理后再用纤维素降解菌降解落叶,研究了酸处理、碱处理、常温浸泡及蒸汽爆破处理对城市落叶生物降解效果的影响.初步试验结果表明,HCl溶液预处理和蒸汽爆破相结合的方法效果最好.通过正交实验分析,蒸汽爆破时间对酶活和落叶降解率的影响大于HCl溶液浓度的影响.在HCl浓度为0.3mol/L,蒸汽爆破时间为20min的最佳预处理条件下,酶活达到27IU,落叶降解率达到33.61%.物理和化学的预处理技术与生物降解相结合,使落叶固废物再利用,减少了环境污染并为葡萄糖生产提供了新的途径.     

苹果早期落叶病的发生规律与防治措施

苹果早期落叶病是苹果褐斑病、斑点落叶病、轮纹病的通称,其中最常见和危害最严重的是斑点落叶病和褐斑病,是生产中最严重的苹果叶部主要病害,文章较详细的介绍了苹果落叶病的病因、症状、发生规律及防治.     

黄土高原西部地区现代木本植被叶片正构烷烃分布模式

采集黄土高原西部地区常见8种乔木及3种灌木植物叶片,利用气象色谱分析,开展现代木本植物叶片正构烷烃主峰分布的研究.结果发现:黄土高原西部地区常见8种乔木植物正构烷烃的主峰分布均以C27或C29为主峰,5种灌木植物中3种以C29为主峰,2种以C31为主峰.乔木植物叶片正构烷烃的分布与前人沉积物中木本植物的研究成果较为一致...