区域高校图书馆的新使命——为“三农”远程信息服务

分析了区域高校图书馆为“三农”开展远程信息服务的必要性和可行性,指出区域高校图书馆为“三农”远程信息服务、促进农村经济发展应采取的对策。     

影响CI-450红外测距仪精度的两个主要参数之修正

对影响CI- 45 0测距仪精度的两项误差 ,即视准轴和测距轴不平行的误差和大气水气压的影响 ,进行了分析和论述 ,并提出了解决问题的方法。     

干基内部根腐深度的研究

１９９０－１９９３年在黑龙江省张广才岭林区的制材厂跟踪纵割实测了５７１根样木并确定将干基内部根腐形状按锥体形状考虑，以研究原条大头端面腐径与干基腐深间的关系，从１２个树种，５８３根样木的４９８个点的回归分析中得出：黑龙江省张广才岭林区囊 中，晚期干基内部根腐的原条，其腐径Φ与腐深Ｈ之间的关系主要是呈线性相关关系，并得出了所研究树种的相应关系式。     

Anatomical changes in the cell-wall structure of Leucaena leucocephala (Lam.) de Wit as caused by the decay fungi Trametes versicolor and Trametes hirsuta

The structural changes in the cell wall and delignification pattern caused by Trametes versicolor and Trametes hirsuta in the sap wood of Leucaena leucocephala were examined by light and confocal laser scanning microscopy. The in vitro decay test was conducted for 12 weeks. Both species of Trametes used in this study caused anatomical characteristics specific to simultaneous white rot. Formation of boreholes, erosion troughs, erosion channels with U-shaped notches in tangential sections and thinning of cell walls were evident in the wood inoculated with each of the fungal species. Cell separation due to removal of middle lamellae occurred at the early stages of infection (30 d) with T. versicolor. In contrast, middle lamellae remained intact in wood inoculated with T. hirsuta and showed cell separation due to degradation of the outer layer of the secondary wall and degradation of the middle lamellae observed only in severely decayed wood at late stages. Confocal microscopy revealed the delignification pattern particularly from cell corners and vessel walls at an advanced stage of decay, indicating strong ligninolytic activity of both species in the sapwood of L. leucocephala.     

内蒙古大兴安岭林区落叶松腐朽的研究 Ⅰ、腐朽菌种类初报

本文报道内蒙古大兴安岭林区落叶松腐朽菌11种.其中两种(扁芝和单色下皮黑)在国内为首次报道落叶松寄主.     

中国古典园林彩画微环境监测及色彩衰变规律研究

为得到微环境参数对古建园林彩画色彩衰变量化影响规律,以颐和园为样本,选取颐和园典型彩画作为研究对象,并开发微环境参数监测系统,对彩画所处微环境信息进行全年实时监测,得到温湿度、风速及照度数据。同时,选取颐和园典型彩画进行周期性测试,提取彩画色坐标及亮度参数,并根据所采集的色彩信息计算出色彩的主波长及兴奋纯度,并拟合主波长、兴奋纯度、亮度随时间的衰变曲线。通过将微环境测试数据与色彩衰变曲线进行对比分析,发现温度、湿度、风速对彩画色彩影响较小,光照是造成彩画色彩衰变的主要因素,而且光照对彩画色相、亮度、兴奋纯度3个参数的影响程度不同,不同颜色受光照影响变化程度也有较大差异。     

荔枝果实采后商品化处理和贮藏技术

荔枝是我国南方著名的主要亚热带果树，但其果实成熟于高温季节，采后由于果皮褐变(即失去红色)和果实腐烂而使果实迅速劣变，常温下的采后寿命少于3 d，这种短的采后寿命严格限制荔枝的长距离贮运、销售和消费。因此，荔枝采后技术研究成为荔枝生产的关键问题。该文全面地介绍了荔枝果实采后腐烂和损失的原因（即荔枝果实的结构特性、生理和病理原因），荔枝果实采后商品化处理和贮藏技术，包括不同品种的耐贮运性、采收成熟度和采收方法、选别和分级、杀菌剂浸泡、减少失水处理、减少果皮褐变和保持果实红色处理（如熏硫处理、酸浸或塑料包装）、检疫杀虫处理、预冷、包装、贮藏（常温贮藏、低温贮藏、气调贮藏、自发气调贮藏）、运输和销售。     

Downed logs improve soil properties in old-growth temperate forests of northern Iran

Dead trees, particularly downed logs, play an important role in the dynamics of forest ecosystem. Contribution of decaying wood to C and nutrient pools of forest soils depends on the tree species and degree of wood decay. However, the extent to which the downed logs affect the soil properties of temperate forests has rarely been evaluated. In this study, a mixed beech forest was selected in Liresar region of Mazandaran Province, northern Iran, to investigate if and how the presence of downed logs affected soil quality and function by comparing soils underneath degraded logs and nearby soils of the two dominant tree species(beech and hornbeam). We then explored how these effects occurred as downed logs decomposed by comparing the woods of both tree species at four degrees of decomposition. Degree of decay of downed logs was classified into four classes(DC1–DC4). Eight dead trees of each tree species were selected at the center of each sample plot. Three composite soil samples underneath each decaying log and 100 cm away from a decaying log were collected at two soil depths(0–15 and 15–30 cm) to analyze soil main physicochemical properties and microbial activity. The results revealed that downed logs affected soil physical(5% wetter than control soils), chemical(2% lower pH, 100% increase in organic C and total N in the case of hornbeam, and 2% increase in P), and biological characteristics(soil microbial respiration enhanced by 10%, and microbial biomass C 620 and 351.5 mg kg~(-1) and microbial biomass N 66.47 and 32.18 mg kg~(-1), respectively, in the cases of beech and hornbeam), thus resulting in significantly different soil microsites from those without downed logs. Presence of downed logs increased soil microbial activity and soil fertility as wood decayed. Thus, the presence of downed logs is an important factor influencing forest soils and should be taken into consideration in forest management practices.     

花烛鲜切花的衰败原因探析

花烛为世界名贵切花,很多品种极易衰败。以往的含银保鲜剂保鲜效果不显著。研究发现,花烛切花的衰败不是由乙烯诱导所致,而是由于其抗逆性减弱,呼吸代谢增强,体内能源物质耗竭,生长促进型激素GA3、Z和ZR的含量降低,生长抑制型激素ABA含量迅速升高,组织、细胞、亚细胞结构被破坏,色素消失所致,最终导致切花变色衰败。     

番茄秧苗运贮中的逆境指标变化

采用生理指标测定等方法进行番茄秧苗运贮试验,结果表明:运贮期间番茄秧苗各项逆境生理指标发生明显而定向的变化,而这些变化表明:番茄秧苗运贮期间的质量下降实质是由于“断光”“断水”而引起的不同于“衰老”的整株型“胁迫性生理衰变”。