浅析园林孤植树造景的生态美

园林植物生态美以园林植物为研究对象,把人-植物-环境看作一个有机整体,从生态和美学两个视角评价植物景观。笔者着重对于孤植树景观的评价,即在满足树木的生态习性要求的前提下,从树木的个体形式、意境效果以及审美心理三个方面进行探讨,提出符合生态美标准及生态园林建设原则的应用方案。     

两种果树叶片SPAD值与叶绿素含量相关性分析

为探究杏、枣树叶片SPAD值与叶绿素含量的相关性,采用SPAD-502叶绿素计与分光光度法分别测定"金太阳"杏与"灵武"长枣叶片的SPAD值、叶绿素含量,分析其相关性,建立拟合方程,并进行检验。结果表明:"金太阳"杏、"灵武"长枣的叶片SPAD值与叶绿素a、叶绿素b、总叶绿素含量间的相关性极显著;"金太阳"杏叶片总叶绿素含量与SPAD值的回归方程为:y=0.0576SPAD-0.4648(R2=0.849**),"灵武"长枣叶片总叶绿素含量与SPAD值的回归方程为y=0.0859SPAD-0.7461(R2=0.8923**)。"金太阳"杏与"灵武"长枣叶片叶绿素含量的实测值与回归方程预测值间均无显著差异。采用回归方程,通过SPAD值可以预测"金太阳"、"灵武"长枣叶片的叶绿素含量。     

喷施6-BA对‘天红2号’苹果苗腋芽萌发及其内源激素的影响

 以当年春季单芽腹接‘天红2号’富士矮化中间砧苹果苗为试材,对6-BA处理后幼苗腋芽萌发生长和萌发过程中内源激素含量的变化和平衡关系进行了研究。结果表明：喷施300 mg · L^-1 6-BA水溶液后,前期单芽质量增长缓慢,4 d后快速增长,5 d时腋芽明显膨大,7 d时萌发,9 ~ 10 d长约1 cm,在处理时苗木顶端以下5 ~ 45 cm平均萌发15个腋芽,萌发株率高达100%。6-BA处理后腋芽内IAA含量初期（大约2 d）明显降低,随后开始缓慢升高,ZRs和GAs含量迅速升高,6 ~ 8 d后二者均开始降低;枝皮内IAA含量显著持续降低,ZRs含量略有降低,6 d后二者均开始缓慢升高,GAs含量变化趋势相反,先升后降;腋芽和枝皮内ABA含量均降低。6-BA处理后打破了顶端优势,枝皮内IAA降低有利于腋芽内IAA向主茎输出,同期调动枝皮中ZRs向腋芽运输,腋芽内ZRs升高,腋芽激活萌发,芽内开始合成大量IAA。随着6-BA作用减弱,4种内源激素含量变化曲线大都在6 ~ 8 d开始回落,同时腋芽萌发,内源激素又开始达到新的平衡。     

外源钙对杏果实裂果的影响研究

从盛花后10 d开始,对大丰杏和硕光杏喷施糖醇螯合钙肥,每隔7 d喷一次,连喷3次.结果表明:幼果期喷钙处理后延缓和减轻了杏果实裂果发生的时期和程度;与对照相比增加了果实内维生素C的含量,大丰杏和硕光杏喷钙后分别提高了1.27 mg/100 g和2.34 mg/100 g;增加了果实内钙含量,大丰杏和硕光杏喷钙后分别上升了12.9%和11.6%,减少了钾含量,降低了钾/钙;提高了果实内SOD的活性,大丰杏和硕光杏分别提高了5.58,2.50 U/(g·h).     

太子山自然保护区主要乔灌木树种分布规律初探

为深入了解太子山自然保护区主要乔灌木树种的分布状况,摸清辖区木本植物资源的具体数量、质量及结构,更好地指导林业生态建设,通过开展专项调查及历史资料的引用分析,表明保护区主要乔灌木树种在垂直及水平分布上具有一定规律性,凸现了生物物种自然选择特征。     

佛山市高明区乡土树木资源调查研究

调查表明广东省佛山市高明区共有乡土树木66科141属218种。其中蕨类植物1科1属1种,裸子植物5科5属5种,被子植物60科135属212种;乔木168种、灌木50种。在这些乡土树木中,用材树种133种、药用植物115种、观赏植物65种、果树25种、油脂植物35种、芳香植物13种、淀粉植物14种、纤维植物31种、鞣料植物24种、蜜源植物5种;珍稀濒危植物6种,国家重点保护野生植物4种。文章分析了这些乡土树木资源的特点,并对资源保护和开发利用提出建议。     

香山公园古树、大树树洞调查及修复

古树、大树年代久远,枝干难免出现空洞,严重影响树木生长,危及树木安全。本文通过对香山公园古树、大树树洞情况调查,分析形成原因,并提出相应的修复措施。       

武汉城区古树资源特征及其应用

文章利用生态学和地理区系成分的方法对武汉市中心城区的古树资源进行资源特征研究,武汉市现有的古树名木共1 130株,隶属26科46属59种,其中刺柏的树龄最大有1 200年,而朴树的数量最多,占22.39%;植被区系具有亚热带向温带过渡的特点,偏重于温带性质;本文还对古树资源应用及其保护提出建议。       

A review on transgenic approaches to accelerate breeding of woody plants

The long juvenile period of trees delays the breeding of new varieties. Flowering begins within 5–10 years in most cultivated forest trees under intensive management, but can take up to 40 years in some species and environmental conditions. To accelerate the breeding process several agrotechnical and biotechnical methods have been developed. Knowledge about genes controlling flower initiation in model plants like Arabidopsis thaliana , and identification of homologous genes in trees, have led to new possibilities for early-flower induction. Overexpression of MADS-box and other floral regulatory genes resulted in early flowering in some tree species and/or varieties. However, these methods have not yet been shown to enable the production of fertile, viable or normal gametes and progeny; developmental research towards these ends is therefore of high priority. A breeding scheme has been developed to use early flowering trees for the introduction of genes from wild species that would allow several backcrosses to occur in only a few years, and to produce at the end a non-transgenic improved variety. Research to develop practical early flowering methods could lead to several new methods for breeding and biotechnology.     

Trade-offs analysis for possible timber-based agroforestry scenarios using native trees in the Philippines

To assess possible new agroforestry scenarios the tree–soil–crop interaction model in agroforestry systems (WaNuLCAS 3.01) was used based on-site specific data collected from Tabango (Central Philippines). Three native timber trees (Shorea contorta Vid., Pterocarpus indicus Juss., and Vitex parviflora Willd.) and one widely spread exotic specie (Swietenia macrophylla King.) were simulated under different intercrop scenarios with maize (Zea mays L.) and subsequently compared. Model simulation results quantified and explained trade-off between tree and crop. For example, higher tree densities will lead to a loss of crop yield that is approximately proportional to the gain in wood volume. However, beside this trade-off effect, there is considerable scope for tree intercropping advantage under a fertilization scenario, with systems that yield about 50% of the maximum tree biomass still allowing 70% of monoculture maize yield. Maximum tree yield can still be obtained at about 20% of the potential crop yield but intermediate tree population densities (400 trees ha⁻¹) and the resulting larger stem diameters may be preferable over the larger total tree biomass obtained at higher tree densities. Another advantage from intercropping systems is that trees directly benefit from the inputs (i.e., fertilizer) that are applied to the crops. The three native trees species studied have different performance in relation to productivity but are similar to (or even better than) S. macrophylla.