贵州多孔菌研究Ⅰ(英文)

　对贵州省宽阔水自然保护区和黔灵山的多孔菌进行了初步研究,共发现多孔菌35种,其中中国新纪录种6个,贵州新记录种19个。3个分类单位只鉴定到属,它们明显是中国以前未报道的种类,或为新种。松生层孔菌Fomitopsispinicola(Sw :Fr )P Karst ,树舌灵芝Ganodermaapplanatum(pers.)Pat ,粗皮灵芝Ganodermatsunodae(Lloyd)Trott 和平丝硬孔菌Rigidoporuslineatus(Pers :Fr )Ryvarden为树木病原菌。

Synthesis of covalently bonded cellulose derivative chiral stationary phases with a bifunctional reagent of 3-(triethoxysilyl)propyl isocyanate

A bifunctional reagent of 3-(triethoxysilyl)propyl isocyanate (TEPI) was initially adopted as a spacer reagent to prepare the bonded types of chiral stationary phases (CSPs) with cellulose derivatives. The silica-based CSPs were chemically prepared with non-regioselective and regioselective approaches and their chiral resolving capabilities were evaluated in terms of HPLC resolution of test enantiomers. It was observed that the chiral recognition capabilities of the non-regioselectively prepared CSPs were influenced by the amount of TEPI used. And also, the regioselectively prepared CSP generally showed a slightly higher resolution power than the non-regioselectively prepared CSP, while the non-regioselective procedures were highly advantageous to rapid preparation. In addition, chiral recognition of the prepared CSPs was affected by the properties of the used silica matrices. (C) 2003 Elsevier B.V. All rights reserved.

Gas permeability of a novel cellulose membrane

A novel cellulose membrane was prepared by using amine oxides as the solvent and its mechanical performance was measured. Steady-state permeation rates of carbon dioxide, hydrogen, methane, nitrogen, oxygen, argon and helium in the homogeneous dense cellulose membrane were measured in the temperature range of 298-353 K and under gas pressures up to 1 MPa. The effect of swelling on hydrophilic membrane permeability was studied in some detail on the cellulose membrane. The difference in gas permeability between the "dry" cellulose membrane and the "water-swollen" cellulose membrane was investigated, and the gas permeability between the cellulose membrane and the Cellophane was compared. In this paper, the separation performance Of CO2 over H-2 in a "water-swollen" cellulose membrane is reported for the first time and the separation factor Of CO2/H-2 can be up to 15. (C) 2002 Elsevier Science B.V. All rights reserved.

黄河源区退化高寒草地土壤种子库:种子萌发的数量和动态

对青藏高原黄河源区不同退化程度高寒草地的土壤种子库土样用土壤分析筛进行浓缩,并以萌发法分析土壤种子库萌发种子数量和动态.结果表明,孔径0.25~2 mm的土壤分析筛分离土样中萌发种子可达萌发种子总量的85%~97%,而小于0.25 mm的土样中未发现种子.因此,用0.25 mm孔径大小的土壤筛对高寒草地土壤种子库土样进行大规模浓缩是一种方便、可靠的方法.4种不同退化程度高寒草地(A:未退化草甸;B:轻度退化草甸;C:中度退化草甸;D:重度退化草甸)的土壤种子库在实验室条件下萌发的种子数量分别为:A 1 194~3 744粒/m2,平均2 421.3粒/m2;B 5 376~1 0912粒/m2,平均7 786.7粒/m2;C 2 304~1 3216粒/m2,平均8 695.5粒/m2;D 4 768~12 352粒/m2,平均8 125.9粒/m2.除样地A外,其它3个样地的可萌发种子数量差异不大.单子叶植物种子在培养到d 10左右开始萌发,双子叶植物在5~7 d内开始萌发,前者3 wk后基本不再萌发,后者5 wk左右停止萌发.4个样地土壤种子库种子萌发主要集中在第2~3周,并表现出近似单峰型格局.图1表3参39

On the induction period of methane aromatization over Mo-based catalysts

The behavior of different species during the temperature-programmed surface reaction (TPSR) of methane over various catalysts is traced by an online mass spectrometer, It is demonstrated that the transformation of MoO3 to molybdenum carbide hinders the activation of methane as well as the succeeding aromatization in the TPSR, If this transformation process is done before the reaction, the temperature needed for methane activation and benzene formation will be greatly lowered (760 and 847 K, respectively). On the basis of comparison of the catalytic behavior of molybdenum supported on different zeolites, it is suggested that the initial activation of methane is the rate-determining step of this reaction. For the cobalt catalysts supported on HMCM-22 or Mo catalysts supported on TiO2, no benzene formation could be observed during the TPSR, However, the prohibition of benzene formation is different in nature over these two catalysts: the former lacks the special properties exhibited by molybdenum carbide, which can continuously activate methane even when multiple layers of carbonaceous species are formed on its surface, while the latter cannot accomplish the aromatization reaction since there are no Bronsted acid sites to which the activated intermediates can migrate, although the activation of methane can be achieved on it. Only for the catalysts that possess both of these properties, together with the special channel structure of zeolite, can efficient methane aromatization be accomplished. (C) 2000 Academic Press.

不同植被恢复模式对黄土丘陵区土壤碳库及其管理指数的影响

为了解侵蚀环境下植被恢复对土壤活性有机碳及碳库管理指数的影响,以典型侵蚀环境黄土丘陵区纸坊沟流域生态恢复30 a植被长期定位试验点为研究对象,选取坡耕地为参照,分析植被恢复过程中土壤碳库各组分和碳库管理指数的演变特征。结果表明,侵蚀环境下植被恢复后土壤碳库各组分含量都得到显著改善,有机碳、活性有机碳和非活性有机碳含量增幅分别为109%~238%,194%~212%和65%~149%,增加速度非活性有机碳>有机碳>活性有机碳。碳库指数和碳库管理指数较坡耕地明显增加,增幅分别为15%~659%和6.5%~414%,说明土壤经营和管理水平较坡耕地得到了显著改善,土壤系统向着良性方向转变。相关性分析表明有机碳、活性有机碳、非活性有机碳、碳库指数、碳库管理指数与土壤主要肥力因子相关性及其密切,可以作为反映生态恢复过程土壤质量演变的指标。不同植被恢复措施可以显著改善土壤碳库含量,增加土壤碳库管理水平,但改善作用不同,总体来说混交林的效果最好,其次为纯林,最后为荒草地,因此在该地区要通过人工促进生态恢复,应以营造混交林为主,纯林为辅的恢复模式。

水肥空间组合对成熟期冬小麦各器官氮磷养分分配的影响

以肥熟土垫旱耕人为土为供试土壤,冬小麦(Triticum aestivum L.)小偃22为供试植物,在全生育期人工控制土壤水分条件下,采用分层隔水土柱法研究了与田间土层分布相同土柱不同土层水分、氮、磷组合对冬小麦不同器官氮、磷养分累积及分配的影响.结果表明:(1)冬小麦不同器官氮、磷累积量表现为籽粒茎秆、叶>穗余部>根系.(2)与整体湿润处理相比,上干下湿水分处理可降低小麦各器官氮、磷累积量,但仅籽粒氮、磷累积量所占比例减少,而营养器官氮累积量所占比例均增加.(3)从肥料处理看,单施氮、单施磷和氮磷配施处理的小麦植株各器官氮、磷累积量均比对照增加,但籽粒氮、磷累积量所占比例均减小.(4)施肥层根系氮、磷累积量比对照相对增加,并以0～30cm土层根系氮、磷累积量为最高.(5)单施氮条件下,以0～90cm土层施肥各器官氮、磷累积量最高,0～30cm土层施肥最低;单施磷和氮磷配施时,以0～90cm土层施肥处理籽粒氮、磷累积量最高,其次是0～30cm土层施肥.由于石灰性土壤中肥料氮终产物以硝态氮为主且容易移动,而磷肥不易在土壤中迁移,在生产实践中仍以氮磷配施入0～30cm土层为佳.

黄延高速公路边坡植被与土壤特性调查研究

采用现场调查、观测、试验等多种试验方法,对黄延高速公路绿化植物、边坡土壤理化性质以及植物群落组成进行了研究。通过分析,总结了中央分隔带、平台和边坡绿化植物种类以及边坡有效配置模式,分析了土壤养分贫瘠的原因和提高措施。在此基础上提出土壤肥力与植物恢复是相辅相成的,土壤肥力随人工植被建立时间的延长而逐渐恢复;随着时间序列的延长,其物种数目和比例也发生较大变化,有利于护坡植物群落最终实现结构稳定。

黄土高原南部3种农田土壤剖面坚实度的变化规律

为了揭示黄土高原南部地区不同质地类型土壤剖面坚实度的变化及其与土壤含水率的定量关系,以黄墡土、土娄土、裸露在地表的粘化层耕作剖面为研究对象,定位观测其0~45 cm土壤坚实度与含水率的变化。结果表明,黄墡土、土娄土、裸露在地表粘化层耕作剖面的犁底层平均坚实度均大于耕层,犁底层平均坚实度较耕层分别高194.8%,87.3%,10.4%;剖面土壤质地越粘其平均坚实度越大;土壤坚实度与含水率呈负相关关系;土壤坚实度变化速率为0时,以上3种土壤剖面临界含水率分别为0.1712,0.1757,0.1835;质地不同的土壤剖面坚实度时空变化特征有差异,其中黄墡土剖面0~20 cm土层土壤坚实度为350~500 kPa,受土壤含水率变化的影响较小;20~30 cm土层土壤的坚实度为500~1400 kPa,不易受外界环境影响;30 cm以下土层土壤坚实度为700~1600 kPa,受土壤含水率变化影响较大。土娄土剖面0~40 cm土层土壤坚实度为600~1200 kPa,受含水率变化影响较大;40 cm以下土层土壤坚实度稳定在1 800 kPa左右。粘化层剖面0~15 cm土层土壤坚实度在2000 kPa左右,受环境影响较...

氯仿薰蒸浸提法测定土壤微生物量碳的改进

对氯仿薰蒸浸提法测定微生物量碳进行改进,使用消煮仪取代恒温电热板进行加热,并优化了升温方式和恒温时间,取得令人满意的试验结果。另外,还对该方法的原理以及试剂的作用和需要注意的事项进行了讨论。最后,将化学法测定结果与仪器分析方法测定结果进行对照,根据测定结果的一致性提出两种测定方式的转换系数应一致。

黄土高原农牧交错区畜牧业可持续发展评析——以吴旗县为例

作为黄土高原半农半牧区重要经济支柱的畜牧业 ,要确保其稳定增长 ,需在提高粮食单产、保障食物安全的前提下 ,保持及改善生态环境 ,通过畜牧业发展农村经济 ,增加农民收入 ,改变农村贫困落后状态。同时畜牧业可持续发展需要经济系统、社会系统、技术系统的共同支撑 ,优化协调畜牧业生产中的外部条件和环境 ,配套解决和优化畜牧业系统内部矛盾是畜牧业可持续发展的必经之路