广东樟木头5种桉树的能量特征研究

对广东省东莞市樟木头林场5种6 a生巨桉(Eucalyptus grandis)、柳桉(E.saligna)、大花序桉(E.cloeziana)、粗皮桉(E.pellita)和托里桉(E.torelliana)的能量特征进行研究.结果表明:5种桉树不同组分的灰分含量和热值存在显著差异(P<0.01).灰分含量为0.16%-8.37%,其中巨桉、柳桉、粗皮桉和托里桉均是叶>皮>枝>根>干,而大花序桉为皮>叶>枝>根>干;各组分的干重热值为15.12-18.85 kJ g~(-1),均以叶最高、皮最低,巨桉与粗皮桉为叶>枝>干>根>皮;柳桉与托里桉为叶>干>枝>根>皮;大花序桉为叶>枝>根>干>皮;去灰分热值为16.37～19.87 kJ g~(-1),除粗皮桉为叶>枝>皮>干>根外,其它4种各组分的去灰分热值均与干重热值的变化趋势相同.5种桉树的平均干重热值和去灰分热值分别以巨桉、粗皮桉最高,但均以托里桉最低.     

人工冬虫夏草的氨基酸含量及其营养价值评价

目的为明确人工和野生冬虫夏草在氨基酸方面的差异,并为进一步开发利用人工冬虫夏草提供理论依据,对室内全人工培殖冬虫夏草和产自四川康定的野生冬虫夏草的氨基酸营养价值进行分析评价。方法用日立L-8800型全自动分析仪检测氨基酸含量并根据FAO/WHO的氨基酸评分标准模式和鸡蛋蛋白模式进行氨基酸营养价值评价。结果人工冬虫夏草氨基酸种类齐全,其全草氨基酸总量高于产自康定的野生冬虫夏草;其全草的鲜味氨基酸高于产自康定的野生冬虫夏草;其全草必需氨基酸总量低于产自康定的野生冬虫夏草。人工冬虫夏草必需氨基酸与氨基酸总量的比值高于WHO/FAO评分模式而低于鸡蛋蛋白模式。结论人工冬虫夏草氨基酸不仅种类组成合理,而且具有较高的营养价值。这一结果为人工冬虫夏草的进一步开发利用提供了理论基础。     

冀东地区西伯利亚白刺开发利用价值研究

西伯利亚白刺是华北沿海地区仅有的一个白剌种,在冀东滨海地区有一定的野生群落分布。研究结果表明,西伯利亚白刺具有极强的耐盐能力,0—50cm土体平均全盐含量最高达到1．97％,极端最高值达到3．99％。其果汁含有非常丰富的维生素C,高达444．07mg／100g,仅次于酸枣,排在各类蔬菜、水果的第二位,是开发功能饮料的上好原料。果实成熟后的嫩茎叶含粗蛋白28．80％,粗纤维8．86％,粗脂肪2．24％,是优质的饲料。种子脂肪含量17．2％,其中油酸含量25．02％,亚油酸含量69．02％,是生产优质保健食用油的好原料。所以,西伯利亚白刺是开发利用重盐碱地和沿海滩涂的优良植物,极具开发价值。     

新安江上游地区黄山市生态补偿价值初探

基于生态补偿价值理论,以2005年为基准年,对新安江上游黄山市生态资源的价值进行研究,分析了上、下游的效益关系,得出黄山市要维持本市自然资源的可持续发展必须对自然资源进行生态补偿的结论,并以生态系统功能的效益作为生态补偿的上限,机会成本和直接投入的总和作为生态补偿的下限,计算出生态补偿总价值量的范围为726963．8．2971790．81万元。     

Relevance of using a vegetation-based method to conserve urban carabid diversity

Urban habitats harbour considerable biological diversity. Ecologists have developed methods to select which habitats should be conserved. The Ecological value, a method based on vegetation, has been created for the urban habitats of Montreal (Quebec, Canada). The main objective of our study was to determine if this method was relevant to assess carabid diversity of Mount Royal Park. This index is calculated using five criteria: uniqueness, representativeness, degree of succession, richness and rarity of the flora, each of which can influence communities of insects. Ground beetles (Coleoptera: Carabidae) were selected because of their success as biological indicators. Despite sampling difficulties, our results demonstrate clearly that the Ecological value method does not represent the high carabid richness of urban open habitats (tall grasses) and their specialised native carabid species. Within forests we found nonetheless that the ecological value index has a significant positive relationship with native carabid abundance. Moreover, maturity and structure of urban forests were positively correlated with carabid abundance and richness. Some urban vegetation characteristics have been shown to influence entomological diversity, but the relevance of using a global floral index to encompass the carabid community seems limited.     

Can soil seed banks contribute to the restoration of dune slacks under conservation management?

Questions: Does the soil seed bank resemble the former early successional stages of a dune slack system more than the established later successional vegetation? Does it have the potential to contribute to the conservation of a highly endangered habitat? Location: Dune slacks at Newborough Warren, UK. Methods: The composition of the soil seed bank in two depth layers was determined using the seedling emergence method between March 2004 and April 2005. Long-term monitoring data on the floristic composition of the established vegetation were obtained from the national conservation agency, and additional monitoring was undertaken in 2003. Floristic composition, seed weights, seed longevity of component species and Ellenberg indicator values were used to compare the seed bank and established vegetation. Results: The soil seed bank was diverse and contained typical dune slack species, species of early successional stages and species of conservation interest. A comparison between the composition of the seed bank and historical data on the composition of the established vegetation showed that the seed bank reflects earlier successional stages more closely than the current aboveground vegetation. This study increases the scarce information currently available on the seed bank ecology of several species, including two orchid species. Conclusions: The soil seed bank can be expected to contribute to vegetation change after disturbance. Stimulation of germination from the seed bank through management may contribute to the conservation of both characteristic and threatened species typical of dune slacks.     

Spatial distribution of benthic algae in the Gangqu River,Shangrila, China

This study consisted of sampling benthic algae at 32 sites in the Gangqu River, an important upstream tributary of the Yangtze River. Our aims were to characterize the benthic algae communities and relationships with environmental variables. Among the 162 taxa observed, Achnanthes linearis and Achnanthes lanceolata var. elliptica were the dominant species (17.10% and 14.30% of the total relative abundance, respectively). Major gradients and principal patterns of variation within the environmental variables were detected by principal component analysis (PCA). Then non-metric multidimensional scaling (NMS) divided all the sites into three groups, which were validated by multi-response permutation procedures (MRPP). Canonical correspondence analysis (CCA) indicated that three environmental variables (TN, TDS, and TP) significantly affected the distribution of benthic algae. Weighted averaging regression and cross-calibration produced strong models for predicting TN and TDS concentration, which enabled selection of algae taxa as potentially sensitive indicators of certain TN and TDS levels: for TN, Achnanthes lanceolata, Achnanthes lanceolata var. elliptica, and Cymbella ventricosa var. semicircularis; for TDS, Cocconeis placentula, Cymbella alpina var. minuta, and Fragilaria virescens. The present study represents an early step in establishing baseline conditions. Further monitoring is suggested to gain a better understanding of this region.     

Effects of Different Potassium (K) Fertilizer Rates on Yield Formation and Lodging of Rice

As one of the most important nutrients for plants, potassium (K) has substantial effects on growth and development of crops. Present study was conducted in three different sites in South China in late season in 2019 with the objective to study the effects of different applied amounts of K fertilizer on yield formation and lodging of rice. Four K fertilizer treatments, K₀: 0 kg potassium oxide (K₂O) ha⁻¹ (control); K₁: 64.20 kg K₂O ha⁻¹ ; K₂: 128.55 kg K₂O ha⁻¹ and K₃ 153.90 kg K₂O ha⁻¹ were applied in the field experiment. The results showed that K₂ and K₃ treatments significantly increased panicle number per unit area, grain number per panicle, seed-setting rate and the grain yield of rice compared with K₀ treatment. Higher net photosynthetic rates were recorded in K₂ and K₃ treatments than K₀ treatment at tillering stage, heading stage and maturity stage. K fertilizer treatments also increased the chlorophyll content and dry matter accumulation by 6.16–23.52% and 21.32–64.59% compared with K₀ treatment, respectively. Moreover, the total N and K accumulation in the aboveground tissues of rice significantly increased under K₂ and K₃ treatments compared with K₀ treatment. Furthermore, compared with K₀ treatment, K fertilizer treatments significantly enhanced the breaking-resistant strength by 40.94–144.24% and reduced the lodging index of rice by 13.14–36.72%.     

漓江流域生态系统服务价值最大化的土地利用结构优化

土地利用结构优化是促进生态系统可持续发展的重中之重,而生态管理的最终目标是优化生态系统服务,使生态系统提供的服务达到最大化。选择典型生态脆弱区漓江流域为研究区,将整个生态系统服务价值的最大化作为研究目标,首先结合野外实验和五期Landsat高分遥感影像获取基础数据,对研究区1998-2018年各项生态系统服务价值进行估算,然后结合灰色线性模型对2018-2028年价值进行预测,借助Lingo软件提出生态效益最大化的土地结构优化方案,进而对优化前后研究区生态系统服务价值进行比较与分析。结果表明：（1）近20年间研究区主要土地利用类型一直以林地与耕地为主,所占比例保持在整个流域的95%。水域与耕地面积逐年减少,林地、建设用地及未利用地面积持续增加。此外,未利用地面积发生的变化最为显著,增加了近30倍,主要由林地与耕地转变而来。（2）研究区生态系统服务价值总体约减少了19.55×10⁶元,呈现先上升后下降趋势,并将长期处于下降趋势,至2028年时流域生态系统服务价值将减少至8067.43×10⁶元。在流域整体生态系统中,林地价值最高,在历年约占流域总价值的86%,其次是水域及耕地,分别占比8%、6%。（3）对研究区进行优化后,漓江流域总生态系统服务价值增长了2%,其中主要来源于林地与水域面积的增加,提高了生态系统调节服务的供给能力,耕地、建设用地面积略微增加,未利用地面积显著减少,基本与2008年水平持平。本研究通过优化喀斯特地区关键生态系统服务价值,为该区域生态管理提供科学支撑。     

基于生态系统服务价值变化的环境与经济协调发展研究——以陕西省为例

为探讨生态环境与经济发展间的协调程度,选取2000、2005、2010和2015年4期的陕西省107个县（区）数据,利用单位面积生态系统服务价值和人均GDP构建环境经济协调度指数。结合空间自相关分析和空间杜宾模型等方法,分析了环境经济协调度指数的时空演变特征及驱动因素。研究表明：（1）从时间上看,陕西省环境经济协调度指数整体呈现缓慢下降趋势;从空间上看,大部分县（区）已处于基本协调和中度协调状态,并形成了陕北地区优于陕南地区,陕南地区优于关中地区的空间格局。（2）陕西省环境经济协调度指数具有显著的空间正相关性,高高集聚和低低集聚效果比较明显。（3）退耕还林工程、城镇化水平、产业结构、降水量是提升协调度指数的关键因素,气温则是制约协调度发展的约束要素。未来应因地制宜实施差异化的发展战略,以实现环境与经济协调发展。