内蒙古图牧吉自然保护区丹顶鹤春季觅食生境初步研究

于2008年5月1~7日,对内蒙古图牧吉国家级自然保护区丹顶鹤觅食地进行了生境因子调查.分析认为,丹顶鹤觅食地主要属沼泽地,其植物主要为芦苇、苔草、水葱、香蒲,植被高度多为100~150 cm,水深约10 cm,水质良好,透明度约为10 cm.     

三江自然保护区丹顶鹤春季觅食生境初步研究

采用样方因子测定法对三江国家级自然保护区丹顶鹤春季觅食生境进行调查研究的结果表明:丹顶鹤春季主要在以苔草、小叶章为主的沼泽湿地中觅食;觅食地植被高度小于40 cm,植被密度低于400株/m2,植被盖度为0～25%,觅食地水深多为5～15 cm,人类干扰距离大于1 500m;人为活动严重影响着丹顶鹤的觅食;春季丹项鹤有在...     

黑河流域湿地植物群落物种多样性研究

以重要值为测度指标,选择反映群落物种多样性、丰富度、优势度和均匀度的4个测定指数,对黑河湿地植物群落物种多样性进行了研究。结果表明:各群落类型的多样性指数的顺序为:芦苇-水麦冬、滨麦-芦苇、芦苇-假苇拂子茅、长苞香蒲、芦苇-扁杆藨草群落、西藏嵩草-芦苇、芦苇-垂穗披碱草、西伯利亚早熟禾、灰脉苔草-西藏嵩草、硬叶苔草、滨麦、芦苇-滨麦-异穗苔草、甘肃臭草、西藏嵩草-小香蒲、小香蒲-假苇拂子茅、芦苇群落。     

3种模拟基质对香蒲和芦苇生理生态的影响

为研究不同性质的基质对香蒲和芦苇2种优势挺水植物生长的影响,模拟了3种基质(100%粘土、50%淤泥+50%粘土和100%淤泥),研究了香蒲和芦苇的生理生态响应情况。结果显示:香蒲叶片的电子传递速率、最大量子产率和光合能力均随基质中淤泥含量的增加而上升,最大电子传递速率(Pm)和对强光的耐受能力(Pm/α)得到强化,株高也随之增加;在50%淤泥+50%粘土混合基质中生长的芦苇,获得最大株高(138.6 cm)和最大叶长(24.5 cm),而在100%淤泥中株高最低;淤泥比例高的基质中生长的植物对强光的耐受能力(Pm/α)略高于粘土比例高的基质中生长的植物。结论:香蒲更适合生长在肥沃的生态环境中,而芦苇则适合生长在营养水平适中的环境中,即50%淤泥+50%粘土的混合基质可能最适合芦苇生长。     

衡水湖常见挺水植物对氮、磷固定及腐烂影响因素研究

以衡水湖常见挺水植物芦苇(Phragmites australis)、香蒲(Typha orientalis Presl.)为对象,研究了其对氮、磷的固定,以及不同温度和不同腐烂时间对氮、磷释放的影响。结果表明:芦苇、香蒲对富营养化水体中的氮、磷具有很好的净化效果,且对氮的固定能力高于磷;芦苇、香蒲在腐烂前期释放氮、磷的强度最大,而后强度逐渐减小。温度较高时促进了芦苇、香蒲的腐烂分解以及对氮、磷的释放。因此,提出了为避免造成水体的二次污染,应在植物进入枯萎阶段前尽快收割。     

蒲河湿地芦苇香蒲对水深的反应及其共生关系研究

芦苇和香蒲是辽宁省湿地内最为常见的挺水植物,主要分布于湿地水岸界到水深1m的区域。本文以沈阳市蒲河国家重要湿地内的芦苇和香蒲作为研究对象通过对81个样方调查,分析了不同水深对芦苇和香蒲生长的影响及芦苇和香蒲的共生关系。结果表明水深和共生对芦苇和香蒲的生长均有显著影响,对芦苇的影响较香蒲更为显著。两种植物在共生竞争时均采用逃避策略,芦苇趋于向浅水区扩展香蒲趋于向深水区扩展。     

北镇新立湖湿地水深对芦苇香蒲共生关系影响的研究

芦苇和香蒲为辽宁省湿地1.0 m水深浅水区域优势物种,研究其共生关系对湿地保护与恢复具有重要意义。该文以北镇新立湖湿地内的芦苇和香蒲作为对象,通过对93个样方调查,分析不同水深对芦苇和香蒲生长及对其共生关系的影响。结果表明:水深显著影响芦苇和香蒲的生长,且对芦苇的影响大于对香蒲的影响。两种水生植物在共生竞争时均采用逃避策略,芦苇趋于向浅水区扩展,香蒲趋于向深水区扩展。     

哈尔滨市9种湿地植物在不同HRT下净污效果研究

选择慈姑、水葱、香蒲、小叶章、菖蒲、泽泻、芦苇、地榆、水莎草9种典型湿地植物,构建小型人工模拟湿地,分析在不同水力停留时间下湿地植物对城市生活污水的净化能力。研究结果表明,最佳的水力停留时间为5 d,植物对COD、TN和TP的平均去除率分别为:55.25%、81.80%、77.51%,均高于对照组;植物对COD的去除能力大小排序为:香蒲>菖蒲>水莎草>水葱>慈姑>小叶章>泽泻>地榆>芦苇;对TN去除能力大小为:香蒲>慈姑>菖蒲>小叶章>水莎草>水葱>泽泻>地榆>芦苇;对TP去除能力的大小依次为:香蒲>小叶章>慈姑>水葱>菖蒲>水莎草>泽泻>地榆>芦苇。综合分析表明,香蒲、菖蒲、水葱和慈姑的净污能力最强,可应用于人工湿地中。     

不同林龄小黑杨、樟子松防风固沙林土壤含水率研究

采取烘干法,对嫩江沙地不同林龄小黑杨、樟子松防风固沙林的土壤含水率进行了研究。结果表明:小黑杨林分,在0~40cm土层,各年龄段林分土壤含水率均高于该土层无林地土壤含水率;在0~20cm土层,随林龄的增加,土壤含水率表现为逐渐下降趋势,在20~40cm土层趋势相反;13年、21年、25年林地0~20cm层土壤含水率均高于同龄林20~40cm层土壤含水率,40~60cm、60~80cm呈无规律性,且均低于同龄林40cm以上土壤含水率。樟子松各林分同层土壤含水率随林龄增长均呈上升趋势,各林龄同层土壤含水率均低于无林地同层土壤含水率(0~20cm土层相反)。     

大山包自然保护区越冬黑颈鹤对觅食地选择的初步研究

对云南大山包黑颈鹤国家级自然保护区越冬黑颈鹤种群所选用的觅食地进行了调查和初步研究。研究结果表明:在其越冬黑颈鹤的家庭鹤与集群鹤两种类群中对觅食地的8种生境因子(坡度、坡向、坡位、植被型、植被盖度、植被高度、最近水源距离和最近干扰距离)及其相对应的项目均表现出有相同的选择性。除家庭鹤更偏好选用上坡位(54.4%)作觅食地,而集群鹤更偏好选用下坡位(44.5%)作觅食地外;对其他因子的选择频次相差不大。对大山包自然保护区越冬黑颈鹤觅食地进行了因子分析,提取了主成分。其结果表明:对越冬黑颈鹤觅食地影响较大的生境因子为植被盖度、植被高度、水源距离和干扰距离。对其两种类群而言,对家庭鹤影响较大的生境因子为植被盖度、坡向、干扰距离和植被高度;而对集群鹤影响较大的生境因子为水源距离、坡向和植被高度。越冬黑颈鹤所选择的觅食地的主要特征具体表现为开阔(植被高度3~10 cm,上坡位(54.5%))、距离水源较近(100~500 m)、植被盖度适中(>40%~<60%)、背风〔东北坡向(45.4%)和西南风(63.6%)〕、缓坡(<30°)、附近有人类活动(距100~700 m)的鸭茅草草地。大山包自然保护区越冬黑颈鹤中家庭鹤与集群鹤对觅食地选用的差别主要表现在水源距离、植被盖度和干扰距离上。     

Armillaria ostoyae in managed coniferous forests in Kastamonu in Turkey

Although several Armillaria species have been reported in Turkey, there is little information about their ecology in Turkish forests. In this study, we investigated five forest stands, approximately 5–74 ha in size, in Kastamonu province in the Black Sea Region of Turkey for the presence of Armillaria species in stumps and logs. The stands were mixed Abies nordmanniana ssp. bornmülleriana and Pinus sylvestris forests managed using a selective cuttings system; the proportion of fir in the total number of stems and stumps ranged from 36 to 98%. Based on sequence analysis of the internal transcribed spacer and intergenic spacer regions of the rDNA, all rhizomorphs sampled from the stumps and logs were of Armillaria ostoyae. The size of the genets was estimated with random amplified microsatellites analysis of the isolates and ranged from single stumps to approximately 450 m². One to seven genets were found in each stand. These results indicate that the genets had arisen from spores and vegetative spread was limited on most sites.     

上海中央公园特大银杏树白蚁防治探讨

通过对上海松江中央公园内65株特大银杏树白蚁为害情况的调查,发现该公园银杏受害率为100%,其中存在活白蚁的银杏占总量的56.9%,采用毒土处理、粉剂疗法、建立白蚁监测点等措施,经过两次灭杀,活白蚁的灭杀率达到92.3%和93.3%,从而使存在活白蚁银杏树的比例从56.9%下降到2.7%,白蚁发生情况明显降低。       

我国食品中农药残留研究进展

随着人们安全健康意识提高,食品中农药残留问题更加受到重视,本文综述了样品预处理研究进展及农药残留快速检测技术研究进展,并简单分析介绍各种方法的优缺点。     

建平半干旱地区石质山地造林技术研究

研究了不同植物在石质山地的造林成活率、土壤化学性质随造林年限的变化和造林措施对土壤化学性质和植物胸径、树高年净生长量的影响。结果表明：不同植物在石质山地的成活率在21%～85%之间,其中白榆和沙打旺的成活率分别为81%和85%,而小叶杨、刺槐、栾树的成活率均在70%左右;植被能明显提高石质山地不同土层的有机质、全N、P2O5含量,但提高程度随土层深度、养分种类和造林年限的不同而不同;在同一土层,生物复合肥料、菌剂和保水剂均显著提高土壤有机质含量（p〈0.01）并显著降低土壤P2O5含量（p〈0.01）;只有保水剂可引起土壤全K含量的明显升高;生物复合肥料、菌剂和保水剂均显著提高白榆、小叶杨、刺槐、栾树树高和胸径的年净生长量,但保水剂的提高程度最高。     

植物DNA甲基化研究进展

植物经常暴露在各种生物和非生物的胁迫之下,这些胁迫会影响植物的生长发育和繁殖并最终导致植物死亡。为了抵御不利的环境条件,植物已经进化出复杂而精细的网络来感知胁迫并激活防御系统。为此,植物激活许多信号转导通路,这些信号转导通路可以改变一些胁迫响应基因的表达,从而引起植物形态、生理和生化的改变以适应逆境。DNA胞嘧啶甲基化是高等真核生物的主要表观遗传机制之一,在维持基因组稳定性和调节基因表达方面起着关键作用。表观遗传变异比遗传变异更为灵活。一旦环境条件发生变化,为了适应新的环境植物都会发生表观遗传的改变。许多研究表明DNA甲基化参与植物的发育和应激反应。基于相关研究对DNA甲基化进行了综述,对植物逆境胁迫有重要意义。     

木材碳封存研究进展

碳封存可以分工业封存和生物封存, 工业封存包括地质封存、海洋封存、矿石碳化以及工业循环利用, 这些方法能快速回收CO₂, 但工艺流程技术复杂, 成本较高。木材碳封存是生物碳封存的一种类型, 树木光合作用吸收的碳主要存贮在木材中。运用木材密度、微密度等检测仪器, 通过确定木材密度变化, 结合其含碳率来计量木材的碳封存过程以及封存过程中碳的分配格局, 同时研究其与环境因子的相关性, 可以为研究森林的碳吸收动态提供便捷的方法和科学的依据。     

Natural regeneration in patch clear-cutting in Picea abies stands in Southern Finland

Abstract

The success of natural regeneration on patch clear-cuts in Norway spruce stands in Southern Finland was examined in terms of stocking and tree height. The experiment was established in mature spruce stands in the submesic Myrtillus (MT) site type. In each of the eight study sites, three plots were treated with clear-cutting and planting, clear-cutting with partial tree retention and planting, and patch clear-cutting without site preparation, respectively. In three of the study sites, one plot with patch clear-cutting and site preparation was established. Each plot was 1 ha, out of which three patches of 40×40 m were clear-cut in the patch treatments. 10–11 years after cutting, the patches had on average 1316 crop trees ha^–1, of which 91% were spruces. Some 27% of the stands were up to the target stocking level (≥1600 ha^?1), and 36% were at least satisfactory (≥1300 ha^?1). Site preparation did not yield greater stocking levels on patches, but that result is ambiguous due to a difference in initial stocking. The average spruce tree height in the patches (0.76 m) was much smaller than in the case of clear-cutting and planting (2.42 m). In conclusion, the patches had been restocked tolerably well with spruce and birch for practical purposes during the 10- to 11-year period, but the regeneration process had been very slow compared to clear-cutting and planting.     

Tree regeneration in patch cutting in Norway spruce stands in northern Finland

The study focused on the success of regeneration on patch cuts in spruce-dominated stands in terms of stocking and tree height. It was based on an experiment in the Kainuu region in northern Finland. The experimental design included 8 stands with 58 clearcut patches of variable size (0.09–0.37?ha), on which either natural regeneration without site preparation or site preparation and planting of Scots pine was applied. A regeneration survey was conducted 13–15 growing seasons after treatments. Patches without site preparation had been restocked quite well from natural seed sources. The average number of trees was about 11,000?ha^?1, of which 1700?ha^?1 crop trees. With site preparation and planting, the stocking levels were also very high, 25,000 and 2100?ha^?1, respectively. One hundred percent of the planted patches and 75% of the naturally regenerated patches had an acceptable density. Restocking was equally good across the range of patch sizes. Tree growth had been somewhat slower in the smallest patches than in the largest ones in the range. Natural regeneration was capable of yielding good regeneration results in most patches, especially when site preparation was applied. Stocking levels and height development were higher yet in the planted patches.     

Changes in micropores in dry wood with elapsed time in the environment

To investigate the changes in microstructures of wood with elapsed time in the environment, CO₂ adsorption onto dry wood was measured at ice-water temperature (273 K) for samples aged from 0.1 years to over 1000 years. The micropore size distribution was obtained using the Horvath-Kawazoe method. Micropores smaller than 0.6 nm in wood decreased in number with elapsed time in the environment, and a negative correlation was found between cumulative pore volume for pores smaller than 0.6 nm and elapsed time in the environment. Cumulative pore volume in the 1000-year sample was almost half of that in the 0.1- year sample. Micropores smaller than 0.6 nm in wood with a few decades or more of elapsed time increased in number after rewetting and drying. Consequently, microstructures of wood with longer time elapsed in the environment were considered to be more stable, because of longer-term thermal motion and possibly more repeated moisture adsorption and desorption and/or temperature variation in the environment.