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Li Y.,Northwest University, China | Li Y.,University of Wisconsin - Madison | Wen C.,University of Wisconsin - Madison | Wen C.,Beijing Academy of Agricultural and Forestry Science | And 2 more authors.
Theoretical and Applied Genetics | Year: 2013

In cucumber, Cucumis sativus L., the spine and skin colors are two important fruit quality traits for variety improvement. In this study, we investigated the inheritance of spine and mature fruit skin colors in F2 and F3 populations derived from a cross between two inbred lines WI7200 (black spine and orange fruit skin colors) and WI7201 (white spine and creamy fruit skin colors). We confirmed that a single, dominant gene, B, controlled both black spine color and orange mature fruit color. Initial framework mapping with microsatellite markers located the B locus in the distal region of the short arm of cucumber chromosome 4. Fine mapping was conducted with draft genome scaffold-assisted chromosome walking and stepwise increase of mapping population sizes, which allowed for the assignment of the B locus to a 50 kb genomic DNA region with two flanking markers that were 0.06 and 0.09 cM, respectively, from the B locus in a mapping population of 2,001 F2 plants. Gene annotation of this 50 kb region identified six genes including one encoding for a R2R3-MYB transcription factor. Sequence alignment of the R2R3-MYB homologs between the two parent inbreds identified a 1 bp deletion in the third intron of this gene in WI 7201. A molecular marker based on this indel was co-segregating with the spine and fruit colors. Quantitative RT-PCR revealed higher level of expression of this R2R3-MYB gene in WI7200 than in WI7201 in both immature and mature fruits. This R2R3-MYB gene seems to be the best candidate gene for the B locus conditioning black spine and orange mature fruit colors of cultivated cucumber. © 2013 Springer-Verlag Berlin Heidelberg (outside the USA).

Yang X.,CAS Institute of Botany | Yang X.,Beijing Academy of Agricultural and Forestry Science | Baskin J.M.,University of Kentucky | Baskin C.C.,University of Kentucky | Huang Z.,CAS Institute of Botany
Perspectives in Plant Ecology, Evolution and Systematics | Year: 2012

Studies on the ecological importance of seed coat mucilage have provided valuable information about its roles in critical stages of the plant life cycle. Seed mucilage may, by providing a moist environment and maintaining metabolic activity in the seed, promote seed development. In seed dispersal, seed mucilage influences topochory, epizoochory, endozoochory and hydrochory by anchorage of seeds to soil surface, lubrication or changing the specific weight of the seed. In arid environments, seed mucilage can prevent seeds from drying or initiate DNA repair mechanisms, thereby maintaining the soil seed bank. Seed mucilage reduces oxygen diffusion to the seed and thus has a role in regulating seed dormancy. Due to it being hydrophilous, acting as a physical barrier and containing chemicals, seed mucilage is proposed to promote seed germination in favorable environments. In seedling growth, seed mucilage may lubricate the radicle as it penetrates the soil and be degraded by soil microfloras and thus promote seedling growth. Further investigation of seed mucilage for more species in diverse habitats from the perspectives of evolution, genetics, proteomics, phylogeny and plant-microbe interactions would contribute substantially to our understanding about its ecological importance. © 2012 Perspectives in Plant Ecology, Evolution and Systematics.

Zhang S.-Z.,Northwest University, China | Li J.-J.,Northwest University, China | Shan H.-W.,Northwest University, China | Zhang F.,Beijing Academy of Agricultural and Forestry Science | Liu T.-X.,Northwest University, China
Biological Control | Year: 2012

Propylaea japonica is one of the most promising biological control agents in northern China. The objectives of the present study were to investigate the preimaginal development, immature survival, reproduction, longevity and fecundity of the ladybeetle, . P. . japonica, when reared on five different aphids species, . Aphis gossypii Glover, . Myzus persicae (Sulzer), . Aphis craccivora Koch, . Acyrthosiphon pisum (Harris) and . Chaitophorus populeti (Panzer) and to quantify their relative suitability as prey. The results of the study indicate that the pre-adult development was shorter (9.9. ±. 0.1. days) when fed on . A. . craccivora but was the longest (13.5. ±. 0.2. days) on . A. . pisum. Immature survival, adult emergence, growth index, development rate, male and female longevity, oviposition period, and fecundity were maximal when . P. japonica were fed on . A. . gossypii. In contrast these biological parameters were minimal on . A. . pisum. The ladybird adult's fresh weight was maximal after feeding on . A. . gossypii and minimal on . A. . pisum. Further analysis revealed linear relationships between rate of development and weight of adult females; and longevity and fecundity of adult females. The results of the present study suggest the order of suitability of aphid species for . P. . japonica is . A. . gossypii>. A. . craccivora>. M. persicae>. C. populeti>. A. . pisum. The present study further propose that either the mass-rearing of . P. . japonica in the laboratory can be carried out by supplying the best food or the understanding its relative abundance in the field in relation to the availability of different prey species. © 2012 Elsevier Inc.

Chen L.,CAS Research Center for Eco Environmental Sciences | Chen L.,Beijing Academy of Agricultural and Forestry Science | Zhang S.,CAS Research Center for Eco Environmental Sciences
Bulletin of Environmental Contamination and Toxicology | Year: 2010

Field experiments were carried out to investigate the dissipation of boscalid in strawberries and soils and its residual levels in strawberries at two different sites. Boscalid (50% water dispersible granule) was applied at two dosages (349.5 and 525.0 g a.i./ha). Soils and strawberry samples were collected at 0, 1, 2, 3, 5, 7, 14, 21 days after application of boscalid. The results showed that boscalid dissipation pattern followed the first order kinetics with the half-lives of 4.9 and 6.4 days in strawberries and 6.1 and 8.0 days in the soils of Jinan and Beijing trail sites, respectively. The boscalid residues in strawberries were below the EU maximum residue level (5 mg/kg) after three days of application. This study suggests that boscalid is acceptable to apply for strawberries under the recommended dosage. © 2010 Springer Science+Business Media, LLC.

Wang M.,Chinese Academy of Agricultural Sciences | Chen L.,Beijing Academy of Agricultural and Forestry Science | Chen S.,Chinese Academy of Agricultural Sciences | Ma Y.,Chinese Academy of Agricultural Sciences
Ecotoxicology and Environmental Safety | Year: 2012

The short-term effects of six types of nanoparticles (NPs) (Kaolin, montmorillonite, hydroxyapatite, Fe 3O 4, α-Fe 2O 3 and γ-Fe 2O 3) on the EC50s (Cd) for root growth of four plant species (i.e. tomato, cucumber, carrot and lettuce) were investigated using standard toxicity testing. NPs and Cd influencing on growth of the plant were as well as tested, respectively. Scanning-electron microscopy (SEM) equipped with the element dispersive spectrometer (EDS) was used to observe the interaction of NPs prepared with EC50s (Cd) as the solvents with the root surface and identify the mechanisms of Cd toxicity reduction to the root growth induced by NPs additives. The results showed that the seedling growth was negatively related to the exposure concentration of Cd, among the tested plants, the sensitive endpoint appeared in the order of tomato>carrot≈lettuce>cucumber according to the ECx measured. The root growth was not significantly inhibited by the presence of NPs except for HAP on tomato, but was noticeably promoted by particular NPs suspensions prepared with EC50s (Cd) as the solvents at higher test concentrations compared with the controls (Cd, EC50s) with one exception for Kaolin. Microscopy images showed roots of tested plants exposed to Cd exhibited a decrease in root diameter and root wilt, and the disintegration of the root epidermis, the clutter root surface showed the evident stress under Cd solution, after the addition of NPs, many root hairs and no disintegration on the surfaces of the root system can be observed, NPs crystal also occurred on the plants root surface. The element dispersive spectrometer (EDS) analysis showed that the precipitation mainly contributed to phytotoxicity reduction by the NPs. © 2011 Elsevier Inc.

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