FT-IR study of the changes in carbohydrate chemistry of three New Jersey pine barrens leaf litters during simulated control burning

Low intensity control burns are a standard fuel reduction management tool used in pine barrens ecosystems. Periodic disturbances through fire can be an important influence on the cycling of nutrients within the ecosystem. Previous studies have shown that the inorganic chemistry of leaf litter residues differs with increasing temperature. Our study compared chemical changes in white oak (Quercus alba), pitch pine (Pinus rigida) and black huckleberry (Gaylussacia baccata), characteristic of the New Jersey pine barrens, during thermal decomposition using FT-IR spectroscopy. Three replicates of senescent leaf material were ground and separately heated for 2 h at: 100, 200, 300, 400 and 550 °C. These temperatures are representative of the range seen in fuel reducing prescribed burns in the pine barrens. Unburned litter of each species was used as a control. An optimization process using varying amounts of KBr and oak litter was performed to develop favorable FT-IR spectral conditions for a sample to KBr ratio of 0.75%. Chemometric analysis of the FT-IR spectra using principal component analysis (PCA) was used to analyze the changes in carbohydrate chemistry of each litter plant species (leaf litter species) at each temperature. In general, it appears that there is clear separation of leaf litter species at the different combustion temperatures. Infrared spectroscopy illustrated that all three species shared wavenumbers characteristic of the primary components of leaves such as cellulose, lignin and hemicellulose. Results from the PCA indicated separation of litter species and species by combustion temperature. PC axis 1 corresponds to the effects of temperature on leaf litter species and PC axis 2 separates the leaf litter species. At the low temperatures (control-200 °C), oak, pine and huckleberry litter species separated from each other. Wavenumbers that contributed to the separation of species at low temperatures belonged to functional group stretching frequencies of outer surface waxes, basic sugars, fatty acids and aldehydes. It appears that oak had more IR bands specific to suberin content. Convergence of these species occurs at 300 °C. Complexity of chemical composition decreases at this particular temperature as is shown by the decrease in wavenumber richness when compared to litters at low and high temperatures. Oak, pine and huckleberry had similar IR spectra showing bands belonging to outer surface wax content, pectin, lignin and hemicellulose. With increasing temperatures (400-550 °C), differences between litter species increased slightly. Plant material was reduced to similar composition due to thermal decomposition, which consisted of inorganic materials such as carbonate, phosphate and sulfate ions and possible fused aromatics.     

泰国输华真柏中一种隐皮孢囊线虫的鉴定

深圳口岸从来自泰国真柏苗木中截获一种隐皮孢囊线虫。序列分析显示截获的孢囊线虫28S r DNA-D2/D3区基因序列与Gen Bank中布林克曼隐皮孢囊线虫(Cryphodera brinkmani)(登录号为JQ965677和DQ328705)的序列相似性为99%。系统进化树中截获的孢囊线虫和布林克曼隐皮孢囊线虫聚为一个分支。结合形态学特征比较和分子特征分析,将截获的孢囊线虫鉴定为布林克曼隐皮孢囊线虫。这是我国口岸首次报道截获该线虫。     

河岸缓冲带硬头黄竹人工林对降水再分配及氮、磷养分的影响

观测了河岸缓冲带硬头黄竹人工林群落2008年1个观测年的大气降雨量、穿透雨量和树干茎流量,并对其取样进行氮、磷养分分析。结果表明：全年降雨量为973.3 mm,穿透雨量和树干茎流量分别为586.0、71.7 mm,占同期降雨量的60.2%、7.4%。以24组不同雨量级数据用线性方程拟合林外降雨量与穿透雨量和树干茎流量间的关系,穿透雨和树干茎流的养分浓度与降雨量呈负相关,表现出明显的季节性变化。全年向林地内输入总氮59.543 kg/hm2,其中NH4＋、NO3-和NO2-的养分含量分别为35.010、20.461、1.423 kg/hm2;输入总磷0.230 kg/hm2,其中PO43-养分含量0.123 kg/hm2,穿透雨和树干茎流带来的养分对竹林的生长和养分循环有重要的生态意义。     

落矶山圆柏幼树生长节律研究

落矶山圆柏直径生长期270 d,树高生长期240 d,生长盛期在4月,其次为5、6月,与春梢、二、三梢相对应,是高生长的主要季节。在生产中应根据上述的生长规律,合理安排松土、除草和施肥等措施。     

四川不同地区3种丛生竹叶片可溶性蛋白分析

以四川省不同地区慈竹、梁山慈竹及硬头黄竹的叶片为材料,测定叶片可溶性蛋白质含量,采用SDS-PAGE技术研究其可溶性蛋白谱带的差异。结果表明,不同地区、不同竹种叶片可溶性蛋白含量及其谱带均有差异,可溶性蛋白含量以雅安地区的梁山慈竹最高,其次为雅安荥经地区的慈竹,宜宾江安地区的硬头黄竹最低;可溶性蛋白谱带慈竹以邛崃地区的为最多,梁山慈竹以雅安地区的为最多,硬头黄竹以宜宾竹海地区的为最多。     

水杨酸对杜松幼苗水分胁迫的缓解效应

采用盆栽PEG处理研究水杨酸对杜松幼苗生长过程中水分胁迫的缓解效应及其可能机制.结果表明:水分胁迫导致杜松幼苗叶片光合色素、游离脯氨酸和可溶性蛋白质含量降低,3种抗氧化酶活性下降.与对照相比,水杨酸处理使幼苗叶片光合色素、游离脯氨酸和可溶性蛋白质含量提高,SOD、POD、CAT活性均提高.     

刺柏硬枝扦插容器育苗技术

从育苗地选择、苗床整理、营养土配制、插穗采集与处理、扦插育苗及苗期管理等环节提出了刺柏容器硬枝扦插育苗技术。     

杜松赤枯病发生规律及防治技术研究

杜松赤枯病是 4年生以上杜松幼树的主要病害 ,在我省为害严重。研究表明 ,此病是由Alternariasp .和Phomasp .共同侵染所致。Alternariasp .以菌丝体和分生孢子越冬 ,Phomasp .以菌丝体和分生孢子器越冬。两种病原菌均通过皮孔、气孔和伤口侵入树体。两种病原菌的孢子均在5月下旬日平均气温达 16℃左右时开始放散 ,孢子的放散和萌发与空气温度的关系最为密切 ,雨季是孢子放散的高峰期。通过对 12种杀菌剂的室内药效测定 ,以及四种杀菌剂的室外防治试验 ,得出用 4 0 0～ 80 0倍液的多菌灵等连续防治 2～ 3年 ,可完全控制该病的发生和蔓延 ,防治方法简便易行 ,成本低廉 ,功省效宏     

引种铺地柏扦插繁育试验研究

对从美国缅因州引进的2个铺地柏品种蓝叶铺地柏和金顶铺地柏进行扦插比较试验,当地品种作对照。试验结果表明：蓝叶铺地柏扦插生根率比金顶铺地柏和当地品种高,为35.78%,且生根数量最多,根长最长,分别为2.9条和26.6 cm;在不同基质扦插铺地柏均能生根,其中1/3蛭石＋2/3珍珠岩基质效果最好。     

北美樱桃核桧引种驯化生长规律及扦插繁殖技术研究

北美樱桃核桧于1987 年引入呼和浩特市树木园,经10a 的引种驯化与3a的无性繁殖试验,证明该树种比当地其他柏类树种更耐旱、耐寒,无病虫害,生长旺盛。经分析北美樱桃核桧生长规律吻合于指数增长方程。10 年生平均树高2 .5 m ,最高达3 .2 m ,针叶呈淡蓝灰绿色,冠形优美,为温带半干旱地区庭院、街道、公园等地绿化的优良新树种。本文着重报道了其生态习性、引种驯化与栽培管理及扦插繁殖技术。