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1.
A new, resource-efficient, herbarium-based method for estimating temporal frequency changes in species, especially of non-vascular plants and fungi, is presented. It is based on a reference data set for the temporal distribution of general collecting activity for the organism group and geographical area of interest. The reference data set includes the collecting year of 650-1000 randomly selected herbarium specimens. The technique relies on the assumption that the temporal distribution of herbarium collections reflects the collecting activity in a region. The temporal distribution of collections of example species is compared with that of the reference data set to correct for the collecting intensity. Thus, cases that are explained by changes in general collecting frequency can be separated from those where other causes are likely. Species of the latter category need to be examined individually in order to assess whether the actual causes for the detected frequency variations are due to environmental changes or other factors. The present method provides a tool to assess actual increases and decreases of moderately frequent to common taxa, to aid in tracing predicted or unpredicted changes in nature.  相似文献   

2.
Populations of wild Beta L. species exist as weeds in commercial sugar beet (Beta vulgaris L. subspecies vulgaris) fields in the Imperial Valley, California. Significant losses to sugar yield and quality result if these wild plants are not removed. In cases of extreme infestation, fields are abandoned without harvest. No selective chemicals are available to differentiate conventional sugar beet from wild relatives and hand removal is labor intensive and expensive. Planting sugar beet varieties with tolerance to glyphosate is a potential solution for infested fields, but risk of gene flow to adjacent wild relatives must be determined. Previous research identified these populations as either Beta vulgaris L. subspecies maritima (L.) Arcang. or Beta macrocarpa Guss. This distinction is critical because B. v. subsp. maritima will readily cross hybridize with cultivated sugar beet while B. macrocarpa rarely will. In April 2011, we collected herbarium samples, mature seed, and leaf tissue from wild Beta populations in 25 infested sugar beet fields throughout the Imperial Valley. Bolting cultivated beets were identified at two locations. Taxonomy of whole plant herbarium samples was unclear due to wild beet stem elongation when under competition with sugar beet plants for canopy light. Morphology of plants from collected seed grown in non-competitive conditions assigned taxonomy of these populations to B. macrocarpa. We used molecular tools to determine the genetic structure of wild Beta populations throughout the Imperial Valley. Extracted DNA was genotyped with 22 simple sequence repeat molecular markers and evaluated for population structure. The bolting beet samples were clearly separated from the majority of B. macrocarpa samples, except for two. The remaining wild populations were further divided into two subgroups suggesting exchange of genetic information or a common ancestor.  相似文献   

3.
秸秆发电燃料收加储运过程模拟分析   总被引：11，自引：4，他引：7  
目前,中国秸秆发电项目的燃料收加储运成本的理论模型分析仍是空白,为了能够有效控制燃料的收加储运成本,掌握不同运输距离下松散秸秆、大秸秆捆的成本变化趋势,该文建立了一个秸秆发电项目燃料收加储运模型,以国内已投入运营电厂的经验数据为基础,通过分析不同模式下的成本变化趋势,对不同收购量及不同收购半径情况下秸秆发电厂燃料收购,提出理想情况下的优化模式,即集中收集和分散收集相结合的模式。对指导秸秆发电厂建立合理的燃料收加储运模式,有效降低燃料成本具有积极的指导意义。  相似文献   

4.
Centaurea solstitialis, commonly known as yellow starthistle, is an invasive plant listed as a noxious weed in the western areas of North America and is the target of classical biological control, which involves release of herbivores known to be specific to this plant. These insects often choose their host plant on the basis of the volatile organic compounds (VOCs) emitted. Accordingly, volatile analysis of host plants can provide insight into VOCs that may attract and/or repel the insect. To this end, solid-phase microextraction (SPME) and a customized collection bag were utilized to perform in situ volatile collection on intact and mechanically damaged leaves of Centaurea solstitialis, Centaurea cyanus, and Centaurea cineraria. Volatile identification was performed by GC-MS, and the VOC differences were determined. The plants C. solstitialis and C. cyanus have been reported to attract the weevil, Ceratapion basicorne, a candidate for biological control, whereas C. cineraria does not attract the weevil. Major VOCs unique to C. cineraria include the sesquiterpenes cyclosativene, alpha-ylangene, and trans-alpha-bergamotene. The compound trans-beta-farnesene was unique to C. solstitialis and C. cyanus.  相似文献   

5.
Floristic survey data from spring wetlands in the Great Artesian Basin of Australia were assessed to generate a ranked list of significant flora values. A system was designed to score endemic species and remote populations of plants, using an extensive herbarium database to set the spring flora in context. The sum of these indices for individual wetland complexes yielded a ranked score. The high priority wetland complexes (scoring five or greater) adequately represent their floristic composition, capture all endemic plant species and 76% of the flora. Although data are limited, many of the high value spring wetlands have endemic fauna of which the snails have been most thoroughly surveyed. The procedure provides direction for an efficient conservation program that if implemented should provide security against a range of threatening processes.  相似文献   

6.
Analysis for sixteen types of Polycyclic Aromatic hydrocarbons (PAHs)from samples of raw and treated wastewater, sediments, sludge andplants growing along treated wastewater way was performed inOctober 1997. The collection sites represent two wastewatertreatment plants (WWTP) receiving different types of wastewaterand one site from disposal of raw wastewater in the city ofKarak in southern Jordan.Wastewater treatment efficiency showed removal of PAHs throughsettling tanks and adsorption on sediments after treatment. Theremoval percentage ranged from 44–100% for individual PAH.PAHs were widely distributed at various levels in rawwastewater, treated wastewater, sludge, sediments and plants.The highest concentration was observed in sludge and the lowestin plants. There was a variation in PAHs concentration betweenthe three investigated sites which was attributed to theefficiency of treatment, period of contact with the wastewater,and the nature of activities. The WWTPs were capable or reducingPAHs contamination in water, up to 40% of the total PAHs byadsorption on sludge and sediments.  相似文献   

7.
一种新型根系分泌物收集装置与收集方法的介绍   总被引：2，自引：0，他引：2  
王占义  潘宁  罗茜  沈宏 《土壤学报》2010,47(4):747-752
根系分泌物在养分活化、改善环境胁迫方面具有重要作用,很多科技工作者对根系分泌物的研究表现出极大兴趣,取得了一系列进展。但土壤栽培条件下,根系分泌物收集是一个难点。本文介绍了一种新型根系分泌物的收集装置与收集方法。该装置由根系生长箱和分泌物收集箱组成,植物在生长箱土壤中生长,通过定向引导作用,根系从生长箱穿过琼脂层进入收集箱中生长,待收集箱内积累一定根系后,通过淋洗收集箱内的介质,实现根系分泌物收集。研究发现,利用该装置收集分泌物,植物总根尖数的90%分布在收集箱。外源有机酸加样回收率可达70%以上。土壤栽培条件下,随生长时期延长,大豆有机酸分泌量逐渐增加,苹果酸分泌量高于柠檬酸。而且土壤栽培条件下大豆柠檬酸和苹果酸分泌量是溶液栽培时的11.4倍和6.7倍。上述研究表明,该装置可以用于土壤栽培条件下根系有机酸的分泌研究。  相似文献   

8.
Interest in bean genetic resources of Central America has resumed because of disease pressures (e.g., web blight, BGMV) and limitations of current bean varieties. As most of the diversity in landraces has been explored, focus is now on the exploration of wild forms of the primary gene pool and wild species of the secondary gene pool. A germplasm collection was carried out in the field and resulted in the collection of 29 wild populations for six Phaseolus species; it complemented field work done in 1987. Nine more populations were found for P. costaricensis, 10 for wild P. lunatus, one for P. oligospermus, one for P. tuerckheimii, four for wild P. vulgaris and four for P. xanthotrichus. Ninety-three herbarium voucher specimens were collected for 19 populations of the six species (deposited at CR). These results confirm the presence of wild P. vulgaris on both slopes of the central valley of Costa Rica, namely in the life zones bh-MB and bmh-P, and of P. costaricensis in the life zone bmh-MB. These life zones of limited range in Costa Rica have been heavily modified, thus fully justifying the germplasm collection for ex situ conservation. For both species the range of distribution in Costa Rica has been almost completely sampled. The life characteristics of each species that are relevant for their conservation in situ are briefly reviewed. Distribution ranges of each wild bean species are compared with the present extension of national parks, protected areas and fauna/flora sanctuaries, and suggestions for expanding such protected areas are made.  相似文献   

9.

The state of Kerala in India, a part of the Western Ghats–Sri Lanka biodiversity hotspot, is blessed with rich biodiversity including agrobiodiversity. Richness in crop diversity is attributed to the wide topographic and climatic niches, long history of outside contacts, personal craving for experimenting new crops, practice of high-density multi-species cropping system, etc. Evidence from several field exploration trips, herbarium survey, reliable literature and other sources has revealed that 306 crop taxa (excluding medicinal and aromatic plants, ornamentals and forestry species) belonging to 290 species coming under 179 genera and 61 families, are being cultivated in different areas of this state. This includes crops belonging to crop-groups—cereals and millets (11), pseudocereals (2), pulses (7), oilseeds (7), fibres (3), forages (14), fruits and nuts (107), vegetables (86; 18-being tuber crops), spices and condiments (20), plantation crops (10) and others (29). Of 306 taxa, 63 occur in the wild state as well; 43 are of only recent cultivation (<?15 years) or under trial cultivation by innovative farmers; and 43 are confined only in (sub)temperate hills. This is more than double (104% increase) the earlier estimate of crops made during 2011, which also included species of medicinal/aromatic/ornamental value (5), not under cultivation in Kerala (3), mistaken identity (3) and synonym (1). We provide here user-friendly crop-group wise categorization of taxa with their vernacular names for easy cross reference. This communication also discusses about the issue of botanical misidentification of crop plants, species of doubtful cultivation status, specialty crops, potential exotic crops, etc.

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10.
Most people in the Swat valley of northwest Pakistan practice subsistence farming, supplementing their income by collecting and selling wild harvested plants for use in herbal medicine. Previous work showed that the collectors did not know the potential long-term impacts of collecting wild plants. We hypothesized that establishment of ex situ cultivation plots for these most valuable species would provide a sustainable alternative and lead to development of skills in agricultural production and marketing among participants. Swat valley farmers were helped to establish plots in four locations and taught to cultivate ten medicinal and aromatic plants (MAPs). In the first year, workshops were held on the financial benefits of growing MAPs for trade, criteria in selecting species, and strategies to improve MAP yield. In the second year, emphasis was placed on helping the farmers achieve a better price for their products by engaging them in discussions concerning criteria used in setting purchase prices. Seven of the ten cultivated MAPs yielded a better financial return than tomatoes (Solanum lycopersicum L.), the traditional cash crop in the area. Cultivating MAPs can yield a higher financial return than traditional cash crops, but a long-term assessment is necessary. Offering training in collection, preservation, and marketing can enhance the financial return and the long-term benefits of cultivation. Introduction of standardized production technology and appropriate post-harvest management has become a prime engine of growth for the economies of the subsistence farmers participating in our study, and is leading to better management and conservation practices for MAPs and the landscapes in which they grow.  相似文献   

11.
人类航天必须解决的基本问题之一，是如何最大限度地利用太阳能光照系统种植作物，大功率的人工光源在其照射作物的同时，还会产生热辐射，能源消耗大。太阳能是目前人类唯一可在太空中获得的外部补充能源。介绍了目前美国用于航天的太阳光收集、输送和分配系统的研究工作，认为该系统的合理利用将有助于降低宇航中作物生长对人工光源的需求。  相似文献   

12.
《CATENA》2005,63(1):39-63
The Monegros desert and its saline wetlands, called saladas (literally translated as “the salties”), are a unique European landscape of great scientific and ecological value. The saladas (i.e., playa-lakes and other small saline depressions) are dynamic environments; changing their surface morphology on a seasonal–diurnal basis in response to both climate and groundwater fluxes. To depict changes in these natural systems, we have identified five surface facies classes which are detectable both in the field and from remote sensing data. These facies are crucial for describing and promoting the protection of these habitats. Remote sensing has provided worthwhile historical data and additional information that compensate for scarce field records. Combined field and satellite criteria are used to catalog these facies with a new conceptual integration that manages the asynchronism between the field and satellite data. The catalog of facies is intended to be helpful for monitoring these wetlands, and for understanding the current hydrological patterns and trends in the playa-lakes. This work will serve as a baseline for studying the future evolution of the saladas which may soon fall under manmade environmental forces such as increased water input from adjacent newly irrigated lands. It is hoped that identification of these facies will be useful, with minor adaptations, in using more advanced sensors or in studying similar habitats.  相似文献   

13.
The Baja California Peninsula is home to 85 species of cacti, of which 54 are endemic, highlighting its importance as a cactus diverse region within Mexico. Many species are under threat due to collection pressure and habitat loss, but ensuring maximal protection of cacti species requires a better understanding of diversity patterns. We assessed species richness, endemism, and phylogenetic and morphological diversity using herbarium records and a molecular phylogeny for 82 species of cacti found in the peninsula. The four diversity measures were estimated for the existing nature reserve network and for 314 hexagrids of 726 km2. Using the hexagrid data, we surveyed our results for areas that best complement the current protected cacti diversity in the Baja California Peninsula. Currently, the natural reserve network in Baja shelters an important amount of the cacti diversity (74% of the species, 85.9% of the phylogenetic diversity, 76% of endemics and all the growth forms). While species richness produced several solutions to complement the diversity protected, by identifying priority species (endemic species with high contribution to overall PD) one best solution is reported. Three areas (San Matías, Magdalena and Margarita Islands and El Triunfo), selected using species richness, PD and endemism, best complement the diversity currently protected, increasing species richness to 89%, PD to 94% and endemism to 89%, and should be considered in future conservation plans. Two of these areas could be included within nature reserves already established.  相似文献   

14.
Garlic and shallot are important vegetable and spice plants, garlic is also a medicinal crop widely used throughout the world. Both belong to the genus Allium, which has been a main target of the taxonomical research at the IPK for many years. Therefore, the IPK’s living collection of Allium is one of the world’s largest special collections of this genus with garlic and shallot being essential parts of this collection. Furthermore, they are subject to special activities to preserve the material in vitro and in cryopreservation. Both methods help protecting valuable germplasm from abiotic and biotic threats and reduce the maintenance costs in the long term. At present, the garlic collection maintained at the IPK incorporates germplasm of 509 accessions in total including all safety duplicates not offered for exchange. Of shallot, 114 accessions are present as well. Passport data as well as phenotypic data of 159 accessions of garlic, one of great headed garlic and 16 of shallot are included in the Garlic and Shallot Core Collection Database (GSCC). An additional part of the database is a comprehensive collection of images illustrating morphological characteristics of the accessions. Exploration of the information is supported by a web-based application. The GSCC is available at http://www.ipk-gatersleben.de/databases/gscc.  相似文献   

15.
Distribution, conservation status, trends, actions and ethnobotanical notes of segetal species growing in South Italy are presented and discussed. For the most threatened segetal species details and suggestions for their conservation are reported. Research work was made directly in the field for collecting samples and in the laboratory for checking several herbarium samples. To the best of our knowledges, a summary table of all species occurring in the field, of the investigated environments, and their ecological focus areas, is provided for the first time.  相似文献   

16.
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17.
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18.
Cacao (Theobroma cacao L.) is a significant agricultural commodity in the Dominican Republic, which ranks 11th in the world for cacao exports. To estimate genetic diversity, determine genetic identity, and identify any labeling errors, 14 SSR markers were employed to fingerprint 955 trees among cacao germplasm accessions and local farmer selections (LFS). Comparisons of homonymous plants across plots revealed a significant misidentification rate estimated to be 40.9 % for germplasm accessions and 17.4 % for LFS. The 14 SSRs amplified a total of 117 alleles with a mean allelic richness of 8.36 alleles per locus and average polymorphism information content (PIC) value of 0.67 for the germplasm collection. Similar levels of variation were detected among the LFS where a total of 113 alleles were amplified with a mean of 8.07 alleles per locus and PIC of 0.57. The observed heterozygosity (Hobs) was 0.67 for the germplasm collection and 0.60 for LFS. Based on population structure analysis 43.9 % of the germplasm accessions and 72.1 % of the LFS are predominantly of the Amelonado ancestry. Among these Amelonado, 51.7 % for the germplasm collection and 50.6 % for LFS corresponded to Trinitario hybrid lineage. Criollo ancestry was found in 7.6 and 9.5 % of the germplasm accessions and LFS, respectively. The Contamana, Nacional, and Iquitos backgrounds were also observed in both populations, but the Curaray background was only detected in the germplasm accessions. No Purús or Guiana ancestry was found in either of the populations. Overall, significant genetic diversity, which could be exploited in the Dominican Republic breeding and selection programs, was identified among the germplasm accessions and LFS.  相似文献   

19.
Although Bois noir is one of the main phytoplasma diseases of grapevine, the gene expression and enzyme activities that underlie physiological changes occurring in symptomatic and recovered (with spontaneous or induced symptom remission) plants are mostly unknown. Bois noir symptomatic leaves (September 2006, 2007) and symptomless leaves from infected symptomatic plants (September 2007) of Sangiovese (moderately susceptible) and Chardonnay (highly susceptible) cultivars were collected. Moreover, leaves from infected symptomless plants of both cultivars were harvested in June 2007. Leaves from recovered plants were also collected in the same periods. In recovered plants of both cultivars, class III chitinase and almost every time phenylalanine ammonia-lyase and chalcone synthase expression were increased for all collection periods. In symptomatic leaves of both cultivars, the expressions of the same genes were up-regulated and also those of β-1,3-glucanase and flavanone 3-hydroxylase. The activities of chitinase, phenylalanine ammonia-lyase, β-1,3-glucanase, and superoxide dismutase generally correlated with gene expression. For the moderately susceptible Sangiovese, the defense genes were generally up-regulated in both symptomatic and symptomless leaves (for all collection periods). This behavior was not observed in the highly susceptible Chardonnay, in which changes in gene expression were linked to evident symptom display. Therefore, the physiological response of the plants to this pathogen infection appear to be the reason for the resistance of the cultivar to the disease.  相似文献   

20.
Vernonia galamensis is a new potential industrial crop with very high content of vernolic acid in the seed oil. The species is known to naturally grow as a weed in fields or in woodlands under a wide range of agroecological conditions of Africa. In order to study the existing variability in Ethiopia, germplasm collection was carried out. Vernonia grows wild in various ecosystems. Ten regions were explored from North, South, East, Southeast, Southwest and Central Ethiopia. A diverse range of habitats having different altitudes and ecological conditions was explored. Altitude of collecting sites varied between 1250 and 2050 m, and soil pH from 5.1 to 8.5. The most common soil type was sandy loam, and the organic matter content varied from 0.2% to 12.9%. At 80 sites, about 480 accessions were collected including different maturity time, plant type, flower color, and branching patterns as well as fatty acid composition. The mean vernolic acid content of the seed oil of the accessions was 74%, and ranged from 34% to 87%. A wide variability in composition of other fatty acids was observed. It was not possible to find Vernonia in some locations that were earlier indicated by herbarium specimens collected since 1840. This could be a sign of change in land use system and environmental degradation and, hence, loss of genetic resources of the species.  相似文献   

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