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PubMed1999

[Grey relational analysis on early bolting of Angelica and its main factors].

Selecting the principal environmental and cultivated factors from the main production areas of Angelica sinensis in Gansu, the problem of early bolting were analysed with grey system theory. After the quantitative analysis, the relational grade was: elevation > precipitaton > density of crop > organic fertilizer > phosphorus fertilizer > nitrogen fertilizer. The research would provide scientific basis for check on the rate of the early bolting of Angelica effectively as well as improve the product and benefits.

Altitude↗
PubMed2004

[Impact of groundwater resource temporal-spatial change in Minqin oasis on ecological security of irrigation region landscape].

By the GIS technology, this paper studied the impact of groundwater resource temporal-spatial change in the lake area of Minqin Oasis on the ecological security of irrigation region landscape. The results showed that the depth of groundwater was descending continuously, the velocity of groundwater line change in the center of irrigation region was faster than that in the edge region, and consequently, the area of the descending funnel of groundwater line was enlarged. From 1987 to 2001, the area with a groundwater depth deeper than 3 m was increased from 81.2% to 97.4%. The descending of groundwater line due to soil water reducing was the main reason that resulted in the destruction and deadness of forests. When the depth of groundwater was deeper than 8 m and soil water content was less than 12%, the die-back rate of tree was morn than 90%, and that of shrub was more than 50%. Impacted by the descend of groundwater depth, the area of forest land, shrub land and open-canopy land was decreased by 67%, 54% and 31%, and the number of their patches was decreased by 35, 42 and 50, respectively. The mineralization degree of groundwater in northern irrigation region increased obviously, and changed the safe pattern of crop growth. The benefit of agriculture decreased, and the adjustment of planting construction was restricted seriously, which became the main impact factor on the ecological security of irrigation region. Reasonably distributing water resource between upper and lower river basin, reducing unreasonable land use, decreasing farmland area, and constructing safety landscape pattern could lead to the balance between the exploitation and replenishment of groundwater resource, prevent the descend of groundwater depth and the increase of groundwater mineralization, and improve the ecological security of the irrigation region.

China↗
PubMed2004

Safe and acceptable strategies for producing foreign molecules in plants.

The ability to express foreign genes using transgenic technologies has opened up options for producing large quantities of commercially important industrial or pharmaceutical products in plants. These technologies have made it possible to use well-developed systems of commercial agriculture that were developed principally to produce raw material for large-scale food, feed or processing applications for the production of foreign molecules. The possibility of the novel industrial or pharmaceutical molecules produced in such plants, or components derived from them, contaminating the environment and food chains has become especially controversial. This potential contamination has prompted detailed consideration of how such crops and the molecules that they produce can be effectively isolated and contained. First, the crop can be completely isolated physically from its food or feed counterpart during every aspect of its development and commercialization. Second, genetic isolation systems or genetic barriers that prevent normal reproduction can be used to reduce the likelihood of the industrial or pharmaceutical crop entering the food chain.

Biotechnology↗
PubMed2005

Abundance, dispersion and parasitism of the stem borer Busseola fusca (Lepidoptera: Noctuidae) in maize in the humid forest zone of southern Cameroon.

This study was conducted in the humid forest zone of Cameroon, in 2002 and 2003. The main objective was to investigate the effects of intercropping on infestation levels and parasitism of the noctuid maize stem borer Busseola fusca Fuller. Two trials were planted per year, one during the long and one during the short rainy season. Maize monocrops were compared with maize/legume or maize/cassava intercrops in two spatial arrangements: maize on alternate hills or in alternate rows. Spatial analyses showed that the stemborer egg batches were regularly dispersed in the maize monocrop and aggregated in the intercrops, as indicated by b, the index of dispersion of Taylor's power law. Depending on the crop association and planting pattern, intercrops reduced the percentage of plants with stem borer eggs by 47.4-58.4% and egg densities by 41.2-54.5% compared to monocropped maize. Consequently, larval densities were 44.4-61.5% lower in intercrops compared to monocrops. Intercropping maize with non-host plants did not affect larval parasitism. Up to two-fold higher levels of egg parasitism by scelionid Telenomus spp. were recorded in inter- compared to monocrops during the short rainy seasons of 2002 and 2003. No differences were found among the mixed cropping treatments and parasitism was lower during the long compared to the short rainy seasons. It was proposed that differences in levels of parasitism were due to density dependence effects rather than the effect of the presence of non-host plants in the system.

Agriculture↗
PubMed2004

Bermudagrass management in the Southern Piedmont USA. V: Gastrointestinal parasite control in cattle.

Parasite-free pastures would improve cattle health and performance, resulting in possible economic return to producers. Our objective was to determine the effect of a single series of anthelmintic treatment of steers prior to stocking on Coastal bermudagrass pastures, during five consecutive summers, on the parasite burden in cattle. The site for this experiment had been conventionally cropped for several decades, with no exposure to cattle, and would be expected to be relatively free of nematode larvae. The experimental design was a randomized complete block (landscape features) with a split plot arrangement of treatments where main plots were pasture fertilization treatments (mineral, clover plus mineral, and broiler litter) and split plots were low and high forage mass. Anthelmintic treatment included pour-on ivermectin on day -21, albendazole on day -7, and injectable ivermectin 48 h prior to stocking of pastures, with the cattle remaining in drylot during the 48-h period prior to being placed on the experimental paddocks. All steers received only one series of treatments during any given year. Yearling Angus steers (Bos taurus) were managed in a put-and-take grazing system with three "tester" steers assigned to each paddock and "grazer" steers added or removed at 28-day intervals. From 1994 to 1998, steers grazed the paddocks for a 140-day period from mid May until early October each year. Fecal samples for worm egg counts were obtained on day 0 and at 28-day intervals, thereafter. On all sampling days after day 0, samples were obtained only from tester animals. Over the 5-year period, the mean eggs per gram of feces (epg) gradually increased from 0 (following treatment) to a mean of 2.2 (range from 0.7 to 3.0) by the end of the grazing season (the last sampling date) in October. Although the epg were not zero, they were below threshold levels that would allow development of a parasite burden in cattle. In traditional management systems, cattle graze parasite-contaminated pastures; therefore, parasites negatively impact growth and productivity throughout the entire grazing period. Periodic anthelmintic treatments simply give a temporary reprieve from those parasitic infections. Conceptually, using the current grazing system, it should be possible to maintain these pastures in a parasite-free status indefinitely; however, from a drug resistance perspective, it would be most applicable in sod-based rotation systems where cattle graze from two to five years before land is returned to row-crops. By removing the effect of parasites, cattle can grow without the physiological constraints that gastrointestinal parasites place on appetite, digestion, nutrient utilization, and general well being.

Albendazole↗
PubMed2002

Do farmers need relief seed? A methodology for assessing seed systems.

This article outlines a methodology to help agencies better determine whether or not relief seed is needed by farmers affected by disaster. A brief review of current seed needs assessment procedures in southern Somalia and Mozambique illustrates problems of knowing which crops and households are affected, the importance of seed access (not just availability) and the need to plan interventions earlier than at present. The development of a Seed Systems Profile (SSP) is proposed to understand better both the socio-economic and agro-ecological aspects of farmers' seed systems. A five-step framework for assessing seed systems in disaster situations is also presented. These tools are currently being tested and further refined in Mozambique. A better understanding of farmers' seed systems will allow for the development of relief and rehabilitation interventions that effectively enhance the resilience and reduce the vulnerability of these systems.

Agriculture↗
PubMedDate not supplied

United States Department of Agriculture-Agricultural Research Service research in application technology for pest management.

A research summary is presented that emphasizes ARS achievements in application technology over the past 2-3 years. Research focused on the improvement of agricultural pesticide application is important from the standpoint of crop protection as well as environmental safety. Application technology research is being actively pursued within the ARS, with a primary focus on application system development, drift management, efficacy enhancement and remote sensing. Research on application systems has included sensor-controlled hooded sprayers, new approaches to direct chemical injection, and aerial electrostatic sprayers. For aerial application, great improvements in on-board flow controllers permit accurate field application of chemicals. Aircraft parameters such as boom position and spray release height are being altered to determine their effect on drift. Other drift management research has focused on testing of low-drift nozzles, evaluation of pulsed spray technologies and evaluation of drift control adjuvants. Research on the use of air curtain sprayers in orchards, air-assist sprayers for row crops and vegetables, and air deflectors on aircraft has documented improvements in application efficacy. Research has shown that the fate of applied chemicals is influenced by soil properties, and this has implications for herbicide efficacy and dissipation in the environment. Remote sensing systems are being used to target areas in the field where pests are present so that spray can be directed to only those areas. Soil and crop conditions influence propensity for weeds and insects to proliferate in any given field area. Research has indicated distinct field patterns favorable for weed growth and insect concentration, which can provide further assistance for targeted spraying.

Agriculture↗
PubMed2004

Irrigation scheduling: advantages and pitfalls of plant-based methods.

This paper reviews the various methods available for irrigation scheduling, contrasting traditional water-balance and soil moisture-based approaches with those based on sensing of the plant response to water deficits. The main plant-based methods for irrigation scheduling, including those based on direct or indirect measurement of plant water status and those based on plant physiological responses to drought, are outlined and evaluated. Specific plant-based methods include the use of dendrometry, fruit gauges, and other tissue water content sensors, while measurements of growth, sap flow, and stomatal conductance are also outlined. Recent advances, especially in the use of infrared thermometry and thermography for the study of stomatal conductance changes, are highlighted. The relative suitabilities of different approaches for specific crop and climatic situations are discussed, with the aim of indicating the strengths and weaknesses of different approaches, and highlighting their suitability over different spatial and temporal scales. The potential of soil- and plant-based systems for automated irrigation control using various scheduling techniques is also discussed.

Agriculture↗
PubMed2026

Penicillium melinii promotes root growth through subtle host reprogramming across model and crop species.

Root development is highly responsive to microbial interactions, yet the mechanisms by which beneficial fungi promote root growth remain incompletely understood. Here, we identified Penicillium melinii 'isolate 2' through a screen of endophytic fungi isolated from Arabidopsis and characterized it as a promoter of root development in both Arabidopsis and crop species. We combined phenotyping in vitro, rhizotron, greenhouse and field assays with reporter and mutant analyses, transcriptomics, phytohormone profiling and sequencing and annotation of the fungal genome to investigate the basis of this interaction. P. melinii consistently stimulated root growth and modified root architecture across experimental systems and host species. These effects were associated with subtle but reproducible host transcriptional reprogramming, supporting a model in which the fungus fine-tunes endogenous developmental programmes rather than broadly perturbing stress or growth pathways. Genetic and reporter analyses further suggested that this interaction modulates root branching through localized developmental reprogramming. Genomic analysis provided a framework for understanding the fungal traits associated with this beneficial interaction. The conservation of the response across model and crop species supports the relevance of P. melinii as both a useful experimental system to study beneficial plant-fungus interactions and a promising candidate for improving root traits and crop performance.

Penicillium melinii↗
PubMed2003

The release of genetically modified crops into the environment. Part I. Overview of current status and regulations.

In the past 6 years, the global area of commercially grown, genetically modified (GM) crops has increased more than 30-fold to over 52 million hectares. The number of countries involved has more than doubled. Especially in developing countries, the GM crop area is anticipated to increase rapidly in the coming years. Despite this high adoption rate and future promises, there is a multitude of concerns about the impact of GM crops on the environment. Regulatory approaches in Europe and North America are essentially different. In the EU, it is based on the process of making GM crops; in the US, on the characteristics of the GM product. Many other countries are in the process of establishing regulation based on either system or a mixture. Despite these differences, the information required for risk assessment tends to be similar. Each risk assessment considers the possibility, probability and consequence of harm on a case-by-case basis. For GM crops, the impact of non-use should be added to this evaluation. It is important that the regulation of risk should not turn into the risk of regulation. The best and most appropriate baseline for comparison when performing risk assessment on GM crops is the impact of plants developed by traditional breeding. The latter is an integral and accepted part of agriculture.

Biotechnology↗
PubMed2006

Understanding regulatory networks and engineering for enhanced drought tolerance in plants.

Drought stress is one of the major limitations to crop productivity. To develop crop plants with enhanced tolerance of drought stress, a basic understanding of physiological, biochemical and gene regulatory networks is essential. Various functional genomics tools have helped to advance our understanding of stress signal perception and transduction, and of the associated molecular regulatory network. These tools have revealed several stress-inducible genes and various transcription factors that regulate the drought-stress-inducible systems. Translational genomics of these candidate genes using model plants provided encouraging results, but the field testing of transgenic crop plants for better performance and yield is still minimal. Better understanding of the specific roles of various metabolites in crop stress tolerance will give rise to a strategy for the metabolic engineering of crop tolerance of drought.

Adaptation, Physiological↗
PubMed1994

Intraspecific metabolic diversity among strains of Burkholderia cepacia isolated from decayed onions, soils, and the clinical environment.

A collection of 218 strains of Burkholderia cepacia (including 18% strain replicates) was assembled from organic soils, decayed onions, and clinical sources. Each strain was characterized for virulence to onion, catabolic ability using the Biolog GN microtiter plate, and several other behaviors. Overall test reproducibility was estimated at 98%. The results obtained using the Biolog GN system corresponded well to those obtained using standard methods. Three coefficients of resemblance (Gower similarity, pattern difference, and Jaccard similarity) were calculated and clustered by the group-average method. The sorted matrices and phenograms, while giving evidence of an underlying phenetic structure to the B. cepacia nomenspecies, gave little evidence of sorting by broad source of isolation. Strains isolated from within fields or samples were frequently found to be similar, however, strains isolated from fields with similar cropping histories were not. The Gower-transformed centroids of ordained clusters were projected in a principal coordinate system and estimates of disjunction were calculated. Strains of B. cepacia were shown to be non-uniformly distributed in taxonomic space. Strains isolated by serial dilution on onion slices formed a tight phenetic cluster which includes the type strain of the nomenspecies and that of a synonymous group (Pseudomonas multivorans); the strains in this phenon were generally virulent to onion and were partially differentiated from others by pectolytic behavior and by the production of diffusible pigment on King's medium A. Further characterization should better resolve the taxonomy of the nomenspecies.

Allium↗
PubMed2005

Removal and recovery of lead(II) from single and multimetal (Cd, Cu, Ni, Zn) solutions by crop milling waste (black gram husk).

The study reports removal of heavy metals when present singly or in binary and ternary systems by the milling agrowaste of Cicer arientinum (chickpea var. black gram) as the biosorbent. The biosorbent removed heavy metal ions efficiently from aqueous solutions with the selectivity order of Pb>Cd>Zn>Cu>Ni. The biosorption of metal ions by black gram husk (BGH) increased as the initial metal concentration increased. Biosorption equilibrium was established within 30 min, which was well described by the Langmuir and Freundlich adsorption isotherms. The maximum amount of heavy metals (qmax) adsorbed at equilibrium was 49.97, 39.99, 33.81, 25.73 and 19.56 mg/g BGH biomass for Pb, Cd, Zn, Cu and Ni, respectively. The biosorption capacities were found to be pH dependent and the maximum adsorption occurred at the solution pH 5. Efficiency of the biosorbent to remove Pb from binary and ternary solutions with Cd, Cu, Ni and Zn was the same level as it was when present singly. The presence of Pb in the binary and ternary solutions also did not significantly affect the sorption of other metals. Breakthrough curves for continuous removal of Pb from single, binary and ternary metal solutions are reported for inlet-effluent equilibrium. Complete desorption of Pb and other metals in single and multimetal solutions was achieved with 0.1 M HCl in both shake flask and fixed bed column studies. This is the first report of removal of the highly toxic Pb, Cd, and other heavy metals in binary and ternary systems based on the biosorption by an agrowaste. The potential of application for the treatment of solutions containing these heavy metals in multimetal solutions is indicated.

Adsorption↗
PubMed1976

Oral food processing in two herbivorous lizards, Iguana iguana (Iguanidae) and Uromastix aegyptius (Agamidae).

The anatomy and function of the feeding apparatus in Iguana iguana and Uromastix aegyptius were studied by dissection, cinematic and cineradiographic techniques. The feeding behavior of these species differs from that of insectivorous lizards in the cropping action involves movement of both the upper jaw around the atlantooccipital joint and the lower jaw around the mandibular joint; and in Uromastix only, streptostylic movement of the quadrate. Often movements of the whole head play a supplementary role in the cropping action. In both species the feeding apparatus has been modified to facilitate cropping. In Iguana the pleurodont dentition is multicusped and laterally compressed. Each tooth forms a shearing blade whose function does not require contact with other teeth. In Uromastix the dentition is acrodont and the cheek teeth are massive and lack cusps. Occlusion is necessary for shearing plant material. The skull system of Uromastix also has a number of modified structures which allow protraction and retraction of the lower jaw to facilitate cropping while maintaining a gape equivalent to that in Iguana. It is suggested that the differences in the feeding apparatus between Iguana and Uromastix are attributable to differeces in the mode of tooth replacement and implantation.

Animals↗
PubMed2006

AgBase: a unified resource for functional analysis in agriculture.

Analysis of functional genomics (transcriptomics and proteomics) datasets is hindered in agricultural species because agricultural genome sequences have relatively poor structural and functional annotation. To facilitate systems biology in these species we have established the curated, web-accessible, public resource 'AgBase' (www.agbase.msstate.edu). We have improved the structural annotation of agriculturally important genomes by experimentally confirming the in vivo expression of electronically predicted proteins and by proteogenomic mapping. Proteogenomic data are available from the AgBase proteogenomics link. We contribute Gene Ontology (GO) annotations and we provide a two tier system of GO annotations for users. The 'GO Consortium' gene association file contains the most rigorous GO annotations based solely on experimental data. The 'Community' gene association file contains GO annotations based on expert community knowledge (annotations based directly from author statements and submitted annotations from the community) and annotations for predicted proteins. We have developed two tools for proteomics analysis and these are freely available on request. A suite of tools for analyzing functional genomics datasets using the GO is available online at the AgBase site. We encourage and publicly acknowledge GO annotations from researchers and provide an online mechanism for agricultural researchers to submit requests for GO annotations.

Agriculture↗
PubMed1997

Risk assessment as a management tool used to assess the effect of pesticide use in an irrigation system, situated in a semi-desert region.

A preliminary study undertaken by the CSIR in July 1993 on the health effects of aerial crop spraying of pesticides in the Vaalharts irrigation area in South Africa indicated that potential health risks could exist for the inhabitants of this area. An extensive scientific health risk assessment and epidemiological study to determine the actual health risks, is very expensive and requires medical and financial justification. The aim of this study was to develop a theoretical health risk model, which could be used as a predictive tool to determine as accurately as possible from the data available if a complete scientific health risk assessment study is justified. The actual amounts of pesticides sold in the Vaalharts area by two major pesticide manufacturers were used to perform a theoretical health risk assessment. The risks were assessed by making use of RISK*ASSISTANT, a computer modeling system and chemical database. The United States Environmental Protection Agency's (EPA) health risk model was applied to the data to identify the hazards, assess the exposures and dose response, and characterize the risks. Three exposure scenarios, namely, the ingestion of food and water and the inhalation of air were evaluated. The method used to calculate the risks varied according to the type of health hazard and the results were characterized accordingly. The acute health effects due to exposure to pesticides are well known and the risks are easy to determine. However, the risks associated with chronic health hazards were more difficult to calculate. For this reason a ranking model was developed which made use ofa point scoring system. This model highlights those pesticides which have the greatest possibility of causing chronic health effects. From the results it can be concluded that very large amounts of pesticides are used in the Vaalharts area and that the community might be at risk to chronic health effects. Although the theoretical health risk assessment model was successfully used in this study, its effectiveness as a predictive tool still has to be proven by a complete scientific study.

Air Pollution↗
PubMed2005

Socio-economic comparison between traditional and improved cultivation methods in agroforestry systems, East Usambara Mountains, Tanzania.

The East Usambara Mountains, recognized as one of the 25 most important biodiversity hot spots in the world, have a high degree of species diversity and endemism that is threatened by increasing human pressure on resources. Traditional slash and burn cultivation in the area is no longer sustainable. However, it is possible to maintain land productivity, decrease land degradation, and improve rural people's livelihood by ameliorating cultivation methods. Improved agroforestry seems to be a very convincing and suitable method for buffer zones of conservation areas. Farmers could receive a reasonable net income from their farm with little investment in terms of time, capital, and labor. By increasing the diversity and production of already existing cultivations, the pressure on natural forests can be diminished. The present study shows a significant gap between traditional cultivation methods and improved agroforestry systems in socio-economic terms. Improved agroforestry systems provide approximately double income per capita in comparison to traditional methods. More intensified cash crop cultivation in the highlands of the East Usambara also results in double income compared to that in the lowlands. However, people are sensitive to risks of changing farming practices. Encouraging farmers to apply better land management and practice sustainable cultivation of cash crops in combination with multipurpose trees would be relevant in improving their economic situation in the relatively short term. The markets of most cash crops are already available. Improved agroforestry methods could ameliorate the living conditions of the local population and protect the natural reserves from human disturbance.

Agriculture↗
PubMed2001

Construction of a shuttle vector and transformation of Xylella fastidiosa with plasmid DNA.

We have isolated, cloned, and sequenced a 5823-bp cryptic plasmid from a strain of Xylella fastidiosa. This plasmid encodes five open reading frames (ORF) greater than 400 nucleotides each. ORF 2 encodes a protein with 37% amino acid identity to the replication initiator protein of plasmid pECB2 from Pseudomonas alcaligenes. This RepA protein from X. fastidiosa contains both a leucine zipper and helix turn helix motif characteristic of proteins involved in DNA replication. The sequence 5' of ORF 2 has all of the features characteristic of plasmid origins of replication as well as regulatory elements required for transcription of ORF 2. Open reading frame 2, along with the upstream origin of replication, was cloned as an EcoRI fragment into pUC19 to create a shuttle vector. This construct was introduced into Xylella fastidiosa by electroporation, with selection for carbenicillin resistance. Transformation was verified by both PCR and Southern hybridization experiments. Frequency of transformation was low, but increased ten-fold when the plasmid was grown in X. fastidiosa rather than Escherichia coli prior to transformation. This work represents the first step towards the development of a system for genetic analysis of this important plant pathogen of citrus, grapevines, and other horticultural crops.

Bacterial Proteins↗