广东山区芳香植物资源区系分析及其园林应用

广东山区野生芳香植物资源丰富,初步统计共有111科311属763种(含变种),包含乔木、灌木、草本和藤本4种生活型。区系成分分析显示：该地区芳香植物科的气候带分布类型以热带至亚热带分布(主产热带)和热带至温带分布(主产热带亚热带)成分为主,分别有29科(占26.1%)和38科(占34.2%),主要集中于木兰科、樟科和芸香科等10个科;属的地理分布区类型多样,以热带成分为主(187属,占60.1%),同时兼有大量的温带成分(99属,占31.8%)。研究发现,本区具有较高观赏价值和园林开发前景的特色芳香植物有     

海南岛甘什岭热带低地雨林植物组成与地理成分

为揭示海南岛甘什岭热带低地雨林区域植物群落特征、性质和规律,以期为进一步分析生物多样性保育与恢复策略及生态服务功能评估等提供科学依据,在海南岛南部甘什岭自然保护区选择典型低地雨林建立1 hm~2固定样地,进行立地因子和植被调查,并研究其物种组成与地理成分。结果表明:维管植物隶属于65科150属213种,种子植物63科148属211种,分别占海南岛和全国种子植物总科、属、种的32.66%、19.29%,13.56%、4.69%和7.65%、0.78%~0.81%;优势科明显,单种科36个,寡种科24个,共占总科数的92.31%;属内种的变化范围为1~6,单种属最多,占总数的76.00%;科和属的分布区类型均以泛热带分布为主,热带性质占绝对优势,这不同于尖峰岭山地雨林热带-亚热带过度性明显的特点;根据种-面积曲线研究表明,甘什岭热带低地雨林最小取样面积为范围在3 600~6 400 m~2之间,其上限高于海南岛霸王岭热带山地雨林的4 000 m~2最小面积;相较于山地雨林,其植物种类较丰富,地理成分更复杂。     

福建连江县5个无居民海岛种子植物区系及地理分布研究

本研究采取样线法和样方法调查相结合的技术路线,对连江5个无居民海岛的植物资源现状进行详细踏勘,根据所获得的实地调研数据以及对文献资料的查阅,运用植物区系地理学,对研究地的种子植物区系物种组成、科-属的分布区类型、分布生境类型等进行统计整理,与不同地区无居民海岛种子植物属的相似性系数和属的地理成分进行对比,并探讨5个无居民海岛之间维管束植物物种相似度以及与岛屿空间特征参数的关系。结果表明：（1）连江5个无居民海岛共有野生种子植物190种,隶属于64科165属;该种子植物区系的数量优势科为菊科、禾本科,大科、较大科、属种优势明显,寡种科、仅含1种的科数量多。生活型以草本（55.94%）和灌木（23.27%）居多,乔木和藤本数量不占优势,分别仅占13.86%和6.93%。（2）区系组成繁杂多样,在科、属水平上均以热带分布类型为首要,分别为90.24%、68.03%,其中泛热带分布分别占科、属的75.62%、36.05%,科级的温带类型只有9.76%,属级占31.97%,热带类型科-属与温带类型科-属的R/T值分别为9.25和2.13,表明连江5个无居民海岛种子植物区系主体为热带、亚热带成分,...     

海南省琼海市药用植物资源调查研究

在第四次全国中药资源普查的工作中,采用实地调查和样地分析相结合的方法,对琼海市药用植物进行了一次较为全面的考察。结果表明,琼海市药用植物资源丰富,类型多样,药用维管植物共计151科536属826种,其中蕨类植物15科17属25种,裸子植物1科1属1种,被子植物135科518属800种。其中以含1~5种药用植物的科占较大比例,达到76.16%;属以单种属占绝对优势。区系分析表明,琼海市野生植物的科的地理成分以热带性质为主。本区植被人为干扰较大,特有种及珍稀濒危植物比例较低,应加强保护力度。     

华侨大学校园种子植物调查与分析

为提供校园植物学教学和绿化的理论依据,丰富城市绿地规划研究内容,对华侨大学种子植物进行了持续调查,并统计分析了种子植物的特点,结果表明：（1）华侨大学种子植物共有568种,来源于118科和375属。其中,裸子植物9科,15属,21种,被子植物109科,360属,547种。原生植物有398种,外来植物有170种。种子植物以原生种类为主,外来植物为辅,不仅具有观赏特点,同时还具有药用价值,乔木和草本植物占优势。（2）优势科、属不明显,单种科和少种科有101科,占总科数的85.60%;少种属和单种属有366属,共占总属数的97.50%,单种科（属）和少种科（属）占重要地位。（3）种子植物地理成分多样,以热带分布为主,热带成分的科共计66科,占校园总科数的77.65%;热带成分的属共计266属,占校园总属数的76.66%。原生植物在科和属的分布类型上较外来植物更丰富,但外来植物在华侨大学分布较广,在绿化建设中仍占有重要地位。     

翁源青云山自然保护区维管束植物区系特征分析

青云山省级自然保护区位于韶关翁源县的东南部,本研究在查阅文献、历史标本的基础上,对本区进行全面踏查、标本采集并鉴定,从而进行植物物种多样性编目和区系分析。结果表明：青云山自然保护区有维管束植物1336种（含种下分类单位）,其中石松类和蕨类植物132种,隶属于62属24科,裸子植物6种,隶属于4属4科,被子植物1198种,隶属于588属148科;本区的表征科主要以樟科（Lauraceae）、壳斗科（Fagaceae）、冬青科（Aquifoliaceae）等为主。植物区系地理组成复杂,主要以热带、亚热带为主,且热带、亚热带的过渡性质明显。从中国特有种的分布情况来看,该地区与湖南南部、广西东北部、江西西南部联系较为紧密,体现了南岭山脉植物区系的一致性与整体性;珍稀濒危植物共计48种;植被具有中亚热带向南亚热带过渡的特征。青云山自然保护区植物物种丰富度高、植被类型多样,建议将园洞、青山口等珍稀濒危植物分布较集中的地区列为优先保护区域。     

南宁市野生种子植物区系研究

为了解南宁市野生种子植物区系特征,给该区域生物多样性的保护与合理开发利用提供科学基础,笔者调查和分析其植物资源,采用文献收集、线路调查和样方调查的统计方法编制出南宁市野生种子植物名录,运用聚类分析法和主成分分析法判断其与15个临近地区的亲缘关系,分析其区系特征。结果表明：南宁市野生种子植物共197科1114属3576种,裸子植物8科14属24种,被子植物189科1100属3552种,占广西种子植物科数、属数、种数比值分别为77.87%、60.02%、42.90%,说明南宁市野生种子植物丰富多样。大科占比为27.41%,所含种数占78.44%,为区系中的主要成分。单种属和寡种属占总属数的85.28%,但中等属和多种属所含种数占总种数51.65%,表明科属种类丰富但分化程度较低。该区系有14个属级分布区类型,地理成分丰富复杂,其中热带成分占总属数69.55%,温带成分占22.16%,呈现明显热带属性,兼具部分温带属性。区域内珍稀濒危植物223种,种类丰富,其中兰科（Orchidaceae）、金花茶（Camellia petelotii）等特有植物种类多,广西植物区域特征明显,保护价值高。该...     

海南中部丘陵区热带次生林物种多样性及区系分析

为弥补海南中部热带雨林区到滨海台地区的过渡地带丘陵区次生林群落物种多样性及区系研究的空缺,为海南中部丘陵地区次生林种子植物区系组成和恢复该地区物种多样性及保育提供理论依据,采用典型抽样法选取海南屯昌丘陵区不同类型次生林,对植物群落的物种多样性、区系地理成分进行调查研究。结果显示调查样地内共有维管植物87科201属267种,其中,蕨类植物3科3属4种,裸子植物2科2属2种,被子植物82科196属261种。群落的优势科为大戟科、茜草科、豆科、蔷薇科、梧桐科及樟科等。分析结果表明,该区种子植物区系起源古老,地理成分复杂,87个科中,世界分布、热带分布、温带分布的科分别有20、59和8个,显示明显的热带性质特征。200个属中,世界分布、热带分布、温带分布的属分别有1、169和30个,种类组成的科、属地理成分热带成分分别为67.81%和84.50%(不包括世界广布的科属),温带成分分别为9.10%和15.00%,表明以热带分布为主。群落垂直结构分为乔木层、灌木层和草本层,物种多样性指数显示,Margalef指数表现出灌木层最大,其次是乔木层、草本层;Shannon-Wiener指数表现为灌木层最大,其次是草本层和乔木层;Simpson指数是灌木层最大,其次是草本层、乔木层;Pielou指数则表现出草本层最大,灌木层其次,乔木层最小。      

海南岛降香黄檀区系组成与群落特征分析

降香黄檀为国家二级重点保护野生植物,海南特有种,是制造高档家具和精美工艺品的上好材料及名贵药材。通过对海南降香黄檀自然分布区实地调查,发现降香黄檀群落包括维管束植物43科68属71种;优势科不明显,单种科和单种属所占比例较大;群落植物区系地理成分多样,以热带成分为主;野生群落分布于石灰岩生境和花岗岩生境两种生境类型;对土壤肥力和酸碱度有一定的适应幅度;其野生资源过度采伐,生境遭到严重破坏。按IUCN濒危等级标准评估,处于“极危濒危”状态。针对降香黄檀濒危现状和原因,提出科学的保育策略。研究结果为该物种的引种驯化提供基础依据,也为可持续经营提供技术支撑。     

江西九连山自然保护区蕨类植物资源调查和分析

通过对九连山保护区蕨类植物的补充调查和统计分析,结果表明：（1）九连山自然保护区共有蕨类植物43科93属265种（含种下等级）,物种组成较丰富,其丰富度指数在江西省的8个森林生态型自然保护区中排第2位;（2）该区蕨类植物中优势科、属明显,优势科为鳞毛蕨科、水龙骨科、蹄盖蕨科、金星蕨科;优势属为鳞毛蕨属、凤尾蕨属、卷柏属、铁角蕨属;（3）在科、属级别的分布区类型中,热带性质成分占绝对优势,分别占总科数和总属数的55.81%和69.89%,在种的地理成分上,以东亚成分占主导地位（占47.9%）,热带性质次之（占34.9%）;（4）该区的R/T值显示该区蕨类植物区系处于南亚热带与中亚热带的过渡区;聚类分析显示,与江西马头山自然保护区、江西齐云山自然保护区的关系最密切,在中国蕨类植物地理分区中属于华东区。     

Comparative Assessment of the Efficacy of Various Nitrogen Fertilizers

Summary

The efficiency of N fertilizers is usually poor; often less than 50% of the applied N is taken up by the crop. This review focuses on various N fertilizers with respect to the significance of different N loss pathways, namely (i) ammonia volatilization, (ii) dinitrogen and nitrogen oxide emissions, and (iii) nitrate leaching. Further, the significance of biological N immobilization, ammonium fixation and, finally, the impact of nitrate vs. ammonium uptake on crop yield are also discussed. The reviewed literature shows that N fertilizers may differ markedly in their susceptibility to losses. There is, however, considerable scope to improve N efficiency of each N source by proper N management practices.     

Novel food and non-food uses for sorghum and millets

Sorghum and millets have considerable potential in foods and beverages. As they are gluten-free they are suitable for coeliacs. Sorghum is also a potentially important source of nutraceuticals such antioxidant phenolics and cholesterol-lowering waxes. Cakes, cookies, pasta, a parboiled rice-like product and snack foods have been successfully produced from sorghum and, in some cases, millets. Wheat-free sorghum or millet bread remains the main challenge. Additives such as native and pre-gelatinised starches, hydrocolloids, fat, egg and rye pentosans improve bread quality. However, specific volumes are lower than those for wheat bread or gluten-free breads based on pure starches, and in many cases, breads tend to stale faster. Lager and stout beers with sorghum are brewed commercially. Sorghum's high-starch gelatinisation temperature and low beta-amylase activity remain problems with regard to complete substitution of barley malt with sorghum malt . The role of the sorghum endosperm matrix protein and cell wall components in limiting extract is a research focus. Brewing with millets is still at an experimental stage. Sorghum could be important for bioethanol and other bio-industrial products. Bioethanol research has focused on improving the economics of the process through cultivar selection, method development for low-quality grain and pre-processing to recover valuable by-products. Potential by-products such as the kafirin prolamin proteins and the pericarp wax have potential as bioplastic films and coatings for foods, primarily due to their hydrophobicity.     

Evolutionary aspects of the trade-off between seed size and number in crops

Whereas the concept that availability of resources drives seed production is sound in principle, it is incomplete as there are many solutions to the allocation of resources that derive from the trade-off between number and size. This paper examines evolutionary aspects of this trade-off in annual grain crops. The analysis is centred on the working hypotheses that, for a given species and environment, allocation of resources to reproduction involves (H1) high plasticity in seed number, which allows for variable resource availability, and (H2) a relatively narrow range of seed size that results from evolutionary and agronomic selection. Comparisons between crops and fish are used to highlight common evolutionary elements in taxa where parents provide little or no care to their offspring, with the consequence that both number and early survival of offspring, hence fitness of parents, are partially related to embryo size and reserves.

The plasticity of seed number in relation to availability of resources is analysed against the established relationship between offspring number and parent growth rate during critical stages. The notion that seed size is under stabilising selection is analysed against three conditions: (1) mean seed size is conservative for a given species and environment, (2) seed size affects fitness, and (3) seed size is heritable. Databases from published papers were compiled to analyse the relative variability of seed size and number, and the heritability of seed size. Evidence for and against the link between seed size and parental fitness is revised using the Smith–Fretwell model as framework (Am. Nat., 108, 499–506).

The proposal of high plasticity of seed number and narrow variability of seed size resulting from stabilising natural selection is generally consistent with evolutionary and genetic considerations. Agronomic selection may have reinforced natural selection leading to relatively narrow seed size in species such as wheat and soybean, where cultivated types retained high plasticity for seed number. In contrast, selection for one or few inflorescences in crops like sunflower and maize may have morphologically reduced seed number plasticity and increased variability of seed size and its responsiveness to resource availability in relation to their wild ancestors.     

Citrus Flavonoids in Fruit and Traditional Chinese Medicinal Food Ingredients in China

Flavonoids-enriched tissues of citrus such as peel, immature fruit and flower are consumed as culinary seasonings, tea ingredients in China for centuries. This HPLC quantitative study on the five citrus flavonoids, naringin, hesperidin, neohesperidin, sinensetin and nobiletin on a wide range of Chinese citrus fruits and several Traditional Chinese Medicinal food ingredients in East China, revealed a great diversity in flavonoid composition. Huyou peel (C. paradisi cv. Changshanhuyou) was found to be the best naringin (3.25%) and neohesperidin (2.76%) source; C. aurantium, a major ingredient of several citrus-related TCM, is also a suitable source of naringin and neohesperidin, and a good juice source for flavanone glycosides; the peel of Wenzhoumiju (C. unshiu) is one of the richest local species in hesperidin (up to 6.25%); Zaoju (C. subcompressa) has the highest content of nobiletin (0.59%), a polymethoxylated flavone. LC-ES-MS analysis of Zanthoxylum genus for flavonoids revealed for the first time the presence of significant amounts (0.74%) of hesperidin in the root of Liangmianzhen (Z. nitidum (Roxb.) DC), a relative of Sichuan pepper, which is a spice widely used in China.     

Effect of a continuous hot water treatment of potato tubers on seed-borne fungal pathogens

Summary The viability of five pathogens was decreased by treatment with hot water when tested in vitro.Polyscytalum pustulans was most sensitive andRhizoctonia solani least sensitive. Potato tubers were exposed to 55°C for 5 min in a commercial continuous hot water treatment plant using naturally contaminated seed tubers and tubers which had been inoculated by dipping in comminuted cultures. The frequency of eyes colonised byP. pustulans, Helminthosporium solani, andR. solani was reduced to virtually zero and the effect persisted on tubers subsequently stored at 4°C and at 15°C for up to 16 wk. Results withColletotrichum coccodes were inconclusive. Treatment suppressedPenicillium spp. which, however, rapidly recolonised the eyes during storage, leading to higher contamination levels in the treated than in the untreated tubers. With tubers inoculated withPhoma foveata, good control was achieved when the incubation period before treatment was 10 d but not when the period was 42 d.     

Role of Benzoxazinones in Cereals

Summary

Heterocyclic 1,4-benzoxazin-3-ones and related benzox-azolinones are important natural products of the cereal crops maize, wheat and rye. Much research has focused on the role of these compounds as defensive agents against plant diseases and pests. Studies of a wide variety of biological effects on herbivores and nematodes, plant pathogenic fungi and bacteria are reviewed in this article. Phytotoxic activity of the compounds is also considered with respect to allelopathic interaction with higher plants. Recent investigations of molecular aspects of interactions of cyclic hydroxamic acids and related benzoxazo-linones with acceptor organisms have demonstrated different effective detoxification strategies and tolerance mechanisms. This research has greatly advanced our knowledge about the multiple roles that these allelochemicals play in ecological systems.     

Potential of dry fractionation of wheat bran for the development of food ingredients,part I: Influence of ultra-fine grinding

Wheat bran is an undervalued by-product of white flour and has great nutritional potential due to its high content in fibres and bioactive compounds. Micronized bran could be used as a food ingredient to improve the nutritional potential of cereal products, or be used as a starting material for other processes (bioactive compound extraction or bran fractionation). The aim of this work was to find a way to efficiently decrease the particle size of bran. The influence of the grinding temperature (ambient or cryogenic grinding) on the granulometric distribution of particles, their composition, and their microstructure was studied, at lab-scale and pilot-scale. It showed that the intrinsic characteristics of bran (glass transition within intermediate layers at −46 °C) had more influence on its grinding behaviour than the type of grinding device used: the particles size distributions obtained after grinding at lab-scale and pilot-scale were very similar. At both scales, the granulometric curves were narrow for cryogenic grinding, while for ambient grinding they were spread over the whole particle size range. Ultrafine particles were obtained in both ambient and cryogenic conditions. Negative temperatures, by increasing the material’s brittleness, favoured a fast fragmentation of bran: one step of cryogenic grinding allowed a median particle size of nearly 50 μm to be reached, whereas three successive steps of ambient grinding were needed for the same result. On the other hand, ambient temperature favoured the dissociation of the different constituent layers of wheat bran, and produced less composite particles than cryogenic grinding.     

Multiple use of plants: Studies on selenium incorporation in some agricultural species for the production of organic selenium compounds

The technique of spraying plants with inorganic forms of selenium can be employed for phytochemical production of organic selenium compounds. Fractionation of the plant material makes it possible to produce a highly concentrated and well defined selenium supplement with potential use in animal and human nutrition. The fractionation also gives opportunities to combine production of organic selenium compounds with other products, for example plant fibres. Multiple use of plants can contribute to a more efficient utilization of land area (in comparison to monocultures solely adapted to food production). It also gives the opportunity to develop systems suitable for long term fixation of carbon, as long as the plant material is not reoxidised to carbon dioxide. Plant fibres could provide raw material for the production of paper or building materials in combination with the production of organic selenium compounds preferentially accumulated in another fraction of the processed plant.     

Biological factors influencing the transmission of potato leafroll virus by different aphid species

Summary Macrosiphum euphorbiae, collected in the field from potato plants infected with potato leafroll virus (PLRV), transmitted the virus to fewer potato plants in a field trial than did laboratory-rearedMyzus persicae. In the laboratory,M. persicae was the only efficient vector of PLRV fromPhysalis floridana seedlings, potato sprouts or excised leaves toP. floridana. Two clones ofM. euphorbiae and one clone ofAulacorthum solani transmitted PLRV from infected potato plants toNicotiana clevelandii as effeciently asM. persicae but a clone ofAphis gossypii was an inefficient PLRV vector. An isolate of PLRV, whichM. persicae transmitted inefficiently from potato toN. clevelandii, was also transmitted inefficiently byM. euphorbiae andA. solani.