多年生花卉的优点与应用

多年生花卉具有6项优点:种类繁多,适应性强,繁殖容易,养护简单,成本低、收效快,群体功能强。充分发挥多年生花卉的优点、合理配置,创造出季相分明、色彩绚丽的园林景观。主要应遵循以下几点原则:遵循花卉的生态习性,做到适地、适花的同时,考虑好花卉之间的关系;与环境相协调,与功能相适应;注重季相、色相的变化和对比;植物的配置有主、有次,叶色、质地、株形的对比富于变化。利用它的群体观赏效果优势,打造出完整的植物群落,为人类创造良好的生存环境。     

论名茶承载的社会功能

名茶作为茶中珍品,不仅能带给人们良好的经济效益,而且在人类社会发展的各个阶段,它始终承载着重要的社会功能。名茶承载的社会功能,主要是交流功能、记忆功能、教育功能和审美功能。     

茶氨酸的生理功能制备方法及应用

茶氨酸是茶叶中特有的、游离的非蛋白质氨基酸,其含量与茶叶品质呈正相关。本文就国内外有关茶氨酸的生理功能、制备方法及应用等方面的研究进展进行了综述。     

Soil degradation by Erosion of a typic hapludalf in central Ohio and its rehabilitation

Soil erosion and runoff were monitored from 1988 to 1990 on a Miamian soil (Typic Hapludalf) of 5-6 per cent slope using field runoff plots. Four treatments were studied: (i) disk-plough up and down the slope to 0.3 m depth (DP); (ii) disk-plough up and down the slope followed by a protective netting (PN); (iii) uncultivated fallow without any vegetation followed by surface soil removal (R); (iv) uncultivated fallow with natural vegetation followed by ploughing (F). Mean annual runoff losses were 6, 114 and 128 mm, or 4, 20 and 18 per cent of the rainfall, and mean annual soil losses were 1.2, 85.0 and 64.0 Mg ha⁻¹ in 1988, 1989 and 1990, respectively. Mean runoff amounts were 26, 69, 116 and 118mm and mean annual soil losses were 0.4, 23.2, 58.6 and 118 Mg ha⁻¹ for the F, PN, DP and R treatments, respectively. In comparison with DP, PN decreased annual runoff by 40.3 per cent and annual soil loss by 79.5 per cent. The high mean soil loss for the R treatment was due to erosion following soil removal. An additional 2920 Mg ha⁻¹ of surface soil was removed from the R treatment in May 1990. The F treatment reduced runoff by 78, 77 and 62 per cent and reduced soil loss by 99.7, 99.4 and 98.4 per cent compared with the R, DP and PN treatments, respectively. Mean losses of K, Ca, Mg and P were 1.3, 4, 1 and 01 kg ha⁻¹, respectively for F, 3, 16, 5 and 0.3kg ha⁻¹, respectively, for PN, 5, 31, 1 and 0.6kg ha⁻¹, respectively, for DP, and 3, 32, 12 and 0.4 kg ha⁻¹, respectively, for R. Soil and nutrient losses for each treatment were in the order R > DP > PN > F. The soil organic carbon (SOC) content was significantly affected by soil erosion and management treatments, and ranged from 0.98 per cent for the R treatment to 2.3 per cent for the F treatment. Soil surface removal for the R treatment in 1990 reduced water-stable aggregates (WSA) by 9.0 per cent, SOC by 0.6 per cent, and clay content of the uppermost 0-50 mm depth by about 7.0 per cent. Mean total porosity (f_t) ranged from 0.43 for the F to 0.52 for the DP treatment. Cumulative infiltration for 3h ranged from 13 cm for R to 34cm for PN, with corresponding infiltration rates of 4 cm h⁻¹ and 13 cm h⁻¹, respectively. Regardless of the treatment, there were also temporal changes in soil properties. In comparison with 1988, measurements made in 1990 showed a significant decrease in WSA of 21.3 per cent, an increase in clay content of 2.8 per cent, and a decrease in SOC of 0.39 per cent. Runoff and soil losses were significantly correlated with the mean weight diameter (MWD), SOC, bulk density (p_b) and available water capacity (AWC). Plant height measured 8 weeks after planting (WAP) for the R treatment was reduced by 33.3 per cent, 33.0 per cent and 29.0 per cent compared withh DP, PN and F, respectively. Nitrogen uptake by maize plants (Zea mays L.) 10 WAP for the R treatment was lower by 15 per cent, 8 per cent, and 6 per cent compared with the DP, PN and F treatments, respectively, while P uptake was lower by 33 per cent, 32 per cent and 29 per cent, respectively, compared with the same treatments. Grain yield was 9.78 Mg ha⁻¹ for PN, 9.76 Mg ha⁻¹ for DP, 8.64 Mg ha⁻¹ for F and 6.60 Mg ha⁻¹ for R during the 1990 crop season. Grain yield was reduced by about 32.4 per cent in the R treatment compared with the PN treatment, representing a maize grain yield reduction of 158 kg ha⁻¹ for each centimeter of soil lost.     

苜蓿转录因子基因Mfhb-1的生物学功能初探

以苜蓿转化植株为材料,利用苜蓿的直接体细胞胚胎发生体系,对苜蓿HD-Zip转录因子基因Mfhb-1的生物学功能进行了初步研究。结果发现,正义转化植株F4(转入基因编码区序列)产生体细胞胚胎时期较对照47/1-5反义转化植株D3(转入编码区的反向序列)和C5(转入编码区+uORF)早,且形成的体细胞胚胎数量远高于对照47/1-5;D3植株产生的体细胞数量较对照少;C5植株产生的体细胞数量较对照少,但比D3稍多。从以上结果可以推测,属于HD-Zip转录因子的Mfhb-1基因能够促进苜蓿体细胞胚胎的发育,并能够提高苜蓿体细胞胚胎发生的数量。     

Spatially heterogeneous impacts on rangeland after social system change in Mongolia

After the social system in Mongolia changed from socialism to capitalism in the early 1990s, the cooperative system called negdel , which helped to disperse the grazing pressure, collapsed. As a consequence of the collapse, scientists warned that grazing pressure would become concentrated and fixed at particular locations, resulting in land degradation. However, no quantitative studies of such potential local concentration have been performed in Mongolia. In this study, using satellite images and large‐scale thematic maps, we analysed the local vegetation change in relation to possible control factors, including open water, roads and settlements. Individual factors had significant impacts on the local vegetation change: particularly prominent were a beltlike decrease in plant density along the main roads and decreases around densely populated areas. In addition, the interaction between these factors negatively affected vegetation, as seen by a decrease around roads and open water near settlements. This interactive effect is likely a consequence of the basic requirements of the nomadic pastoralists, namely quality grassland, water sources and the services provided by settlements. In our study area in Mongolia, the local pattern of vegetation change was determined by the complex process of pastoralists' decision‐making. A comprehensive understanding of this process is essential for devising management plans to counteract this vegetation degradation. Copyright © 2007 John Wiley & Sons, Ltd.     

大学校园绿地景观设计探讨

高校扩招后校园绿色空间变窄,校园生态文化缺失,该文在此背景下分类提出大学校园绿地景观设计要求与原则。       

我国东北地区农业功能区划研究

本文在分析农业功能区划分的指导思想、目标和原则的基础上,设置了农产品供给功能、就业和社会保障功能、文化功能、生态功能和障碍因素等5个农业功能分区指标组,采用逐步判别聚类法完成东北农业功能指标的空间聚类,将东北地区划分为东北平原国家农产品生产基地区、辽东城乡一体化发展区、农牧交错生态脆弱区、长白山老爷岭林地区、大小兴安岭林地区、呼伦贝尔草原牧区等6个农业功能区,并分析提出了各区功能定位和东北农业可持续发展政策建议.     

室内几何测试条件对土壤高光谱数据离散性的影响

利用方差分析方法,研究了光源照射角度、探头距离、光源距离3个几何测试条件对室内土壤高光谱数据离散性的影响.结果表明,探头距离对室内高光谱样本曲线的离散性影响不明显,而光源照射角度、光源距离对室内高光谱样本曲线离散性影响的显著性与选取的研究波段范围有关,除B1波段(400～900nm)外,都达到了极显著水平.在该试验研究条件下,15°的光源照射角度、15cm的探头距离和30cm的光源照射距离是较理想的室内测试几何条件组合.     

用小区平均值估算单株遗传力的方法

子代测定中以小区平均值进行了方差分析及估算遗传力,单株遗传力的结果误差较大,用小区平均值作为方差分析,外加计算了小区内方差及调和平均株数,进而计算方差成分及遗传力,其结果与采用单株数据估算的结果相近,即使在试验数据严重不平衡的情况下,也不例外,该法可有效节省计算机资源及时间,该文以实例详细介绍了有关的计算方法。