氮素营养对长白落叶松移植苗生长及养分状况的影响

尽管少数研究认为造林效果与苗木体内氮含量无关甚至负相关(Gleason et al.,1990;Boinvin et al.,2004),更多的研究表明初始氮含量与造林效果呈正相关,如蓝桉(Eucalyptus globulus)高、低氮处     

中度火干扰对白桦落叶松混交林土壤理化性质的影响

应用空间代替时间的方法对大兴安岭林区白桦落叶松混交林1982-2007年的中度火烧迹地土壤理化性质变化进行研究.结果表明:火后土壤密度增加,土壤孔隙度和土壤含水率降低,但是变化幅度将随着时间的推移逐渐缩小,并在火烧后第20年将接近火烧前水平;火烧后A层和B层土壤有机质均呈降低趋势,A层的降幅逐渐缩小直到火烧后20年比火烧前水平大幅增加;火后土壤A层和B层全磷含量均呈增加趋势,土壤全氮在A层基本也呈增加趋势,B层随火后时间呈波动变化,无明显规律;土壤有效磷含量变化星先降低后增加的趋势;A层土壤速效钾含量的变化基本呈增加趋势,但随时间增加幅度减小,而B层的变化无规律;A层土壤水解氮含量变化呈增加趋势,而B层的变化则与速效钾在B层的变化相似,无明显规律.此研究旨在找出火烧后随时间的推移土壤理化性质的动态变化规律,为火烧迹地的改造和生态恢复提供科学依据.     

修枝对欧美杨107杨水分生理的影响

以欧美107杨为研究对象,从树干液流、蒸腾速率(Tr)以及叶水势(LWP)等杨树水分生理指标角度,探讨修枝处理对这些生理指标在生长季(6—9月)内的影响及其变化规律,并做相应的分析和讨论。试验地Ⅰ以4年生107杨为样木,试验地Ⅱ以6年生107杨为样木。试验地Ⅰ,Ⅱ均设计3个处理组,每个处理组设有3种处理,即对照处理CK(不修枝)、中度处理P1(修掉树冠高度的1/3)、重度修枝P2(修掉树冠高度的2/3)。研究结果表明:1)发生旱情季节(6—8月),液流通量及液流速率呈现P1>CK>P2的规律;正常月份(9月),液流通量及液流速率呈现出CK>P1>P2的规律;P1的液流通量及速率在旱季或正常月份大小基本相同。这表明同正常月份未修枝CK相比,适当修枝(P1)使杨树树干液流始终保持在一定的较低水平,抗旱能力得到一定程度的提高。2)整个生长季内,蒸腾速率(Tr)和叶水势(LWP)都呈现出CK相似文献   

A new neuroprotective bakkenolide from the rhizome of Peatasites tatewakianus

Constituents of the fruits of Peatasites tatewakianus were investigated. A new compound, namely bakkenolide-VI (1), was isolated. The structures was elucidated on the basis of 1D, 2D NMR, TOF-MS and ESI-MS techniques, and physicochemical properties. The neuroprotective activity of the new compound was assayed with primary cultured neurons exposed to oxygen-glucose deprivation and oxidative insults.     

Neuroprotective labdane diterpenes from Fritillaria ebeiensis

By bioactivity-guided isolation, two labdane diterpenes (1 and 2) have been isolated from the bulbs of Fritillaria ebeiensis. Their structures were elucidated as 6α,7β-dihydroxy-labda-8(17),12(E),14-triene (1) and 6-oxo-2α-hydroxy-labda-7,12(E), 14-triene (2), on the basis of spectroscopic data analysis (IR, ESI-MS, HR-ESI-MS, 1D and 2D NMR). Both of the isolates showed neuroprotective effects against MPP⁺-induced neuronal cell death in human dopaminergic neuroblastoma SH-SY5Y cells.     

An in vivo analysis of the therapeutic and synergistic properties of Chinese medicinal formula Yin-Chen-Hao-Tang based on its active constituents

6,7-Dimethylesculetin (D), geniposide (G) and rhein (R) are the three major active ingredients of Yin-Chen-Hao-Tang (YCHT), a famous Chinese herbal formula, which has been shown to be clinically effective for treating hepatic injury (HI) syndrome. The present study was conducted to investigate the therapeutic and synergistic effects of COC (combination of D, G and R) on HI rats by combining pharmacokinetic with biochemical analysis strategy. Plasma was analyzed by using reversed-phase high performance liquid chromatography (RP-HPLC). Principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) models were built to evaluate the therapeutic and synergistic effects of COC at the biochemical level. Here, we report that the COC combination could increase the plasma level, slow elimination rate, exert a more robust therapeutic effect than any one or two of the three individual compounds by hitting multiple targets in a rat model of HI. Overall, this beneficially accounts for the popular view that traditional Chinese medicine (TCM) formula usually takes multi-component to exert their therapeutic effects. We suggest that dissecting the mode of action of clinically effective formula to be capable of producing a sufficient effect at low doses.     

Bioactive saponins from the fruits of Aesculus pavia L

Continued chemical investigation on the fruits of Aesculus pavia L. resulted in theisolation and identification of two new oleanolic acid saponins, namely vaccaroside A (1) andvaccaroside B (2). The isolated furostanol saponins were evaluated for cytotoxic activity againsthuman normal amniotic and human lung carcinoma cell lines using neutral red and MTT assays.In vitro experiments showed significant cytotoxicity in a dose dependent manner with IC50 valuesin the range of 27.80–79.02 μM.     

安徽省山核桃产业发展现状、存在问题及对策

概述了安徽省山核桃产业发展现状、生产经营中存在的问题与不足,并对安徽省山核桃产业发展提出了以科技为依托,市场为导向,加快标准园建设、品牌建设,培育龙头企业,推进山核桃产业健康持续发展的对策与建议。     

枫杨研究进展

枫杨是我国长江中下游地区广泛分布的重要优良乡土树种和速生丰产造林树种.笔者从种源、育苗造林、群落分布、材性、淹水、灭螺等方面总结了枫杨研究进展情况,对枫杨培育和综合利用以及开展枫杨的速生丰产研究具有重要的理论价值和实际意义.     

襄垣北石底山的林业复垦与生态重建研究

依托国际先进的宫胁造林法,襄垣北石底山林业复垦基础工程和植被恢复工程取得阶段性成果。简要阐述了襄垣北石底山的环境概况,重点介绍了林业复垦基础工程的再造技术,植被重建工程的植物筛选以及建植技术和管护技术。实践证明,侧柏纯林,侧柏、灌木混交林,油松、栎类、灌木混交林这3种林分结构在太行山的废弃石灰岩生态重建中比较合理,侧柏作为先锋树种为改善微环境和恢复森林植被创造了有利条件。