Survival and long-term growth of eucalypts on semi-arid sites in a Mediterranean climate,South Africa§

Four experiments were established on the semi-arid west coast plain of South Africa during the 1990s. The trails tested the survival and growth of several eucalypt species and hybrids, some of which were established in a climate that is drier than their natural distribution range. The aridity indices (AI; defined as mean annual precipitation [MAP]/mean annual potential evapotranspiration) ranged from 0.21 to 0.36 and MAP from 228 to 423 mm. The driest trial site (AI = 0.21 and MAP = 228) had high levels of mortality. However, a number of species (in particular, Eucalyptus gomphocephala, E. camaldulensis and E. tereticornis, as well as individual hybrids of the latter two species with E. grandis) survived and grew well at the remaining sites. Eucalyptus cladocalyx survived well and attained competitive growth rates only on the wettest site in the group (AI = 0.36). The dominant height of the top-performing genotypes at age 5 ranged between 9 and 10 m on the two wetter sites. This corresponded to mean annual increment values in excess of 10 m³ ha^?1 a^?1, which is comparable to volume obtained at more favourable aridity indices in the summer rainfall zone of South Africa and exceeds the growth rates obtained in several other arid zone studies globally. The E. grandis × E. camaldulensis hybrid ranked among the top performers in two trials, but its susceptibility to recently introduced pests and relatively poor wood quality makes it a less attractive choice for planting. The high density and durability of timber, acceptable growth rate (given the low rainfall conditions), and low pest and disease incidence make E. gomphocephala and E. cladocalyx the species of choice for planting in the drier and relatively wetter sections of the semi-arid zone, respectively.     

湘西民间竹编产业开发潜力与对策

湘西竹资源丰富,民间竹编历史悠久。挖掘和发扬传统竹编工艺,发挥当地竹材资源优势,推动湘西竹编产业化发展,是实现当地居民增收致富的有效途径。文章详细分析了湘西竹编产业化发展的潜力,提出了促进湘西民间竹编产业化发展的对策。     

西部退耕还林(草)工程生态与经济协调发展途径的选择

通过农民问卷调查结果和退耕还林(草)工程特点的分析,以解决农民关心的焦点问题和反映工程的两重性特点为依据,提出实现退耕还林(草)工程生态与经济协调发展目标的两条途径,这就是:政策调动;产业化发展。     

Influence of sulfometuron methyl on conifer seedling root development

On three sites in coastal northwestern Oregon, USA, seedling root and shoot development were assessed for Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), western hemlock (Tsuga heterophylla (Raf.) Sarg.), and western red-cedar (Thuja plicata Donn ex D. Don) container seedlings under varying sulfometuron methyl (Oust XP^®) herbicide application treatments. Treatments consisted of application of 0.16 kg active ingredient (ai) ha^?1 as a site preparation in fall 2003, a release application in fall 2004, or a control treatment with no application. Seedlings were planted in winter 2004 and measurements recorded in summer 2004, winter 2005, and summer 2005. During first season growth, western red-cedar seedlings showed the greatest negative impact to site preparation compared to the control with overall average new root length outside the root plug reduced by 67%. Significant reductions in root length also occurred for western hemlock (47%) and Douglas-fir (40%) seedlings. About 9 months after the release treatment, and 21 months after the site preparation application, there were no significant differences between treatments for any measured parameter. These findings suggest that seedlings under the site preparation treatment recovered from initial damage incurred to the root system. Lack of seedling response under the release treatment may be the result of opposing influences from the herbicide application associated with seedling phytotoxicity and enhanced seedling development resulting from effective vegetation control. Although our study was limited to 21 months following planting, reduced vegetation cover in the site preparation and release treatments suggests that these treatments may benefit future seedling growth.     

浅谈西部环境法律体系建设与完善

指出了为适应深入实施西部大开发的发展战略,加强西部地区的生态建设,要求建立与完善与其相适应的环境法律法规。从西部环境保护的法律体系现状出发,分析了现有环保法律体系的不足。同时,从自然和社会两方面提出了完善现在法律体系的措施,并强调了国家机关、社会组织、公民的监督的作用。     

银杏苯丙氨酸解氨酶基因的克隆和序列分析

根据其他植物PAL基因的DNA序列的保守区域，设计了一对简并引物，经PCR扩增，得到一条862 bp的特异性扩增带。将PCR扩增产物构建到T-载体并测序，获得了862 bp DNA序列。通过分析所得的862 bp DNA序列及其编码的氨基酸序列，与其他植物PAL基因的DNA序列和蛋白质序列分别进行比较，证实了所得序列为银杏PAL基因的部分序列。Gbpal1已经被Genebank收录，序列号为AY578145。Southern杂交结果表明银杏PAL是一个多基因家族。     

Non-mycorrhizal fungal endophytes in two orchids of Kaiga forest (Western Ghats), India

We used standard isolation protocols to explore the endophytic fungal communities in three tissue types of two dominant orchids (Bulbophyllum neilgherrense and Vanda testacea) of the Kaiga forest ofthe Western Ghats. We surface sterilized and assessed 90 segments ofeach orchid for the occurrence and diversity of endophytic fungal taxa.The 118 fungal isolates were obtained from root, bulb and leaves of B.neilgherrense, consisting of 17 anamorphic taxa (range, 10 15 taxa) with 1.3 fungal taxa per segment (range, 1.2 1.4 taxa). Four taxa (Aspergillus flavus, A. niger, Penicillium sp. and morpho sp. 1) belonged to the coregroup (11.1% 32.2%). The relative abundance of A. flavus and morpho sp.1 was more than 10%. A total of 130 fungal isolates from roots, stems and leaves of V. testacea yielded 20 anamorphic taxa (range, 11 15 taxa)with 1.4 fungal taxa per segment (range, 1.4 1.5 taxa). Aspergillus flavus,A. niger, A. ochraceus, Gliocladium viride, Penicillium sp. and morphosp. 1 belonged to the core group. Relative abundance exceeded 10% for A. flavus, A. niger, and morpho sp. 1. The Simpson and Shannon diversity indices were higher in leaf than root or bulb/stem of both orchids.Jaccard’s similarity coefficient was higher between root and leaf in both orchids (56.3% 60%) than between other pairs. Our study revealed thatthe endophytic fungal assemblage and diversity of B. neilgherrense and V.testacea of Kaiga forest of the Western Ghats were relatively similar between orchids and their tissues.     

湘西虎杖抑菌成分提取及其抑菌活性研究初报

以乙醇作溶剂,对湘西虎杖抑菌活性物提取条件进行研究,通过抑菌实验得到最佳提取条件为A3B2C3,即90%乙醇、60℃、3h, 该条件下的提取物对细菌生长的抑制活性最强,但对酵母菌无明显的效果,对三种受试细菌的最小抑菌浓度(MIC)为0.25~ 0.5g/ml。提取物经85℃、100℃,15 min 或pH2~8 处理后仍具有较强的抑菌活性,其乙酸乙酯萃取物对三个菌都有较强的抑菌活性。     

近代广东住宅园林布局特点浅析

因受特定的历史背景、人文地理和气候环境的影响,近代广东住宅园林独具特色,既继承了传统岭南园林的环境适应性和人文要素,又扬弃融合了西方园林的造园手法。文章着重研究近代广东住宅园林的布局特点,特别是中西合璧的造园手法所形成的布局样式和风格,为现代园林的设计与实践提供新的视角。     

富含多糖的转基因石斛基因组DNA提取方法(英文)

在石斛兰转基因研究中,需通过PCR和Southern杂交等手段检测外源基因是否转入并整合到转化植株基因组.由于转化石斛植株生长缓慢,且含有多糖,因此从转化植株中提取高质量的基因组DNA以尽快对转基因苗进行分子检测存在较大困难.本研究旨在通过改良现有的DNA提取法(CTAB法或SDS法1,克服转化石斛植株基因组DNA提取中碰到的产量低,纯度不高而导致难以进行PCR或酶切等问题.在本研究所用的3种改良法中,方法Ⅱ能从少量的转化石斛苗中提取出高产量和高纯度的基因组DNA.研究结果表明方法Ⅱ提取的基因组DNA完全适用于转基因石斛的外源基因PCR扩增,限制性酶切和Southern杂交分析.