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Source Plants (source + plant)
Selected AbstractsMedium, Explant and Genotype Factors Influencing Shoot Regeneration in Oilseed Brassica spp.JOURNAL OF AGRONOMY AND CROP SCIENCE, Issue 5 2003G. X. Tang Abstract The effects of culture media, explants and genotypes on shoot regeneration in oilseed Brassica species were examined in this study. The maximum shoot regeneration frequency was obtained in Murashige and Skoog medium supplemented with 3 mg l,1 6-benzylaminopurine and 0.15 mg l,1 1-naphthaleneacetic acid. The addition of 2.5 mg l,1 AgNO3 was very beneficial to shoot regeneration in B. napus and Ag2S2O3 (10 mg l,1) was even superior to AgNO3 (2.5 mg l,1). Explant age, explant type and carbon source also significantly affected shoot regeneration. Four-day-old seedlings of cotyledonary explants showed the maximum shoot regeneration frequency and number of shoots per explant. Of the four explants , peduncles, hypocotyls, cotyledons and leaf petioles , cotyledons produced the highest shoot regeneration frequency (56.67 %). Four carbon sources , glucose, maltose, starch and sucrose , were compared for their respective effects on shoot regeneration from cotyledonary explants. Sucrose appeared to be the best carbon source for shoot regeneration with the highest shoot regeneration frequency (76.00 %). Considerable variation in shoot regeneration from cotyledonary explants was observed both between and within Brassica species. The shoot regeneration frequency ranged from 10.00 % for cv. R5 (B. rapa) to 83.61 % for cv. N1 (B. napus). Two B. napus, one B. carinata and one B. juncea cultivars exhibited shoot regeneration frequency higher than 70 %. In terms of the number of shoots produced per explant, B. rapa showed the highest variation, ranging from 5.64 for cv. R3 to 1.33 for cv. R5. Normal plantlets were regenerated from all induced shoots and developed normally. The regenerated plants were fertile and identical with the source plants. [source] Susceptibility of source plants to Sugarcane Fiji disease virus influences the acquisition and transmission of the virus by the planthopper vector Perkinsiella saccharicidaJOURNAL OF APPLIED ENTOMOLOGY, Issue 1 2006K. Dhileepan Abstract:, Fiji leaf gall (FLG) caused by Sugarcane Fiji disease virus (SCFDV) is transmitted by the planthopper Perkinsiella saccharicida. FLG is managed through the identification and exploitation of plant resistance. The glasshouse-based resistance screening produced inconsistent transmission results and the factors responsible for that are not known. A series of glasshouse trials conducted over a 2-year period was compared to identify the factors responsible for the erratic transmission results. SCFDV transmission was greater when the virus was acquired by the vector from a cultivar that was susceptible to the virus than when the virus was acquired from a resistant cultivar. Virus acquisition by the vector was also greater when the vector was exposed to the susceptible cultivars than when exposed to the resistant cultivar. Results suggest that the variation in transmission levels is due to variation in susceptibility of sugarcane cultivars to SCFDV used for virus acquisition by the vector. [source] Transmission of Pepino mosaic virus by the Fungal Vector Olpidium virulentusJOURNAL OF PHYTOPATHOLOGY, Issue 4 2010Ana Alfaro-Fernández Abstract Transmission of Pepino mosaic virus (PepMV) by the fungal vector Olpidium virulentus was studied in two experiments. Two characterized cultures of the fungus were used as stock cultures for the assay: culture A was from lettuce roots collected in Castellón (Spain), and culture B was from tomato roots collected in Murcia (Spain). These fungal cultures were maintained in their original host and irrigated with sterile water. The drainage water collected from irrigating these stock cultures was used for watering PepMV-infected and non-infected tomato plants to constitute the acquisition,source plants of the assay, which were divided into six different plots: plants containing fungal culture A (non-infected and PepMV-infected); plants containing fungal culture B (non-infected and PepMV-infected); PepMV-infected plants without the fungus; and plants non-infected either with PepMV and the fungus. Thirty-six healthy plants grouped into six plots, which constituted the virus acquisition,transmission plants of the assay, were irrigated with different drainage waters obtained by watering the different plots of the acquisition,source plants. PepMV was only transmitted to plants irrigated with the drainage water collected from PepMV-infected plants whose roots contained the fungal culture B from tomato with a transmission rate of 8%. No infection was detected in plants irrigated with the drainage water collected from plots with only a fungus or virus infection. Both the virus and fungus were detected in water samples collected from the drainage water of the acquisition,source plants of the assay. These transmission assays demonstrated the possibility of PepMV transmission by O. virulentus collected from tomato crops. [source] Estimation of the seed dispersal kernel from exact identification of source plantsMOLECULAR ECOLOGY, Issue 23 2007JUAN J. ROBLEDO-ARNUNCIO Abstract The exact identification of individual seed sources through genetic analysis of seed tissue of maternal origin has recently brought the full analytical potential of parentage analysis to the study of seed dispersal. No specific statistical methodology has been described so far, however, for estimation of the dispersal kernel function from categorical maternity assignment. In this study, we introduce a maximum-likelihood procedure to estimate the seed dispersal kernel from exact identification of seed sources. Using numerical simulations, we show that the proposed method, unlike other approaches, is independent of seed fecundity variation, yielding accurate estimates of the shape and range of the seed dispersal kernel under varied sampling and dispersal conditions. We also demonstrate how an obvious estimator of the dispersal kernel, the maximum-likelihood fit of the observed distribution of dispersal distances to seed traps, can be strongly biased due to the spatial arrangement of seed traps relative to source plants. Finally, we illustrate the use of the proposed method with a previously published empirical example for the animal-dispersed tree species Prunus mahaleb. [source] Comparative whitefly transmission of Tomato chlorosis virus and Tomato infectious chlorosis virus from single or mixed infectionsPLANT PATHOLOGY, Issue 2 2009A. Dalmon Tomato chlorosis virus (ToCV) and Tomato infectious chlorosis virus (TICV) are two criniviruses that are emerging worldwide, and induce similar yellowing diseases in tomato crops. While TICV is transmitted only by Trialeurodes vaporariorum, ToCV is transmitted by three whitefly species in two genera Trialeurodes vaporariorum, T. abutilonea and Bemisia tabaci. The efficiency of transmission by T. vaporariorum from plants infected by one virus or by both was compared, and the probability of virus transmission by a single whitefly was derived from group testing experiments. The estimated transmission probabilities ranged from 0·01 to 0·13, and were not significantly different between ToCV and TICV, or between single and mixed infections. Experiments using B. tabaci as a vector and source plants infected by TICV and ToCV did not reveal any functional trans-complementation for transmission of TICV by ToCV, suggesting that if this phenomenon occurs in nature, it is at a very low frequency. Possible reasons why TICV did not establish in southern France while ToCV is now endemic are discussed. [source] Conidial dispersal by Alternaria brassicicola on Chinese cabbage (Brassica pekinensis) in the field and under simulated conditionsPLANT PATHOLOGY, Issue 5 2003L. Y. Chen This study investigated conidial dispersal in the field, and effects of simulated wind and rain on the dispersal of A. brassicicola on Chinese cabbage (Brassica pekinensis). Spores were sampled using a Burkard volumetric spore sampler and rotorod samplers in a Chinese cabbage crop. Disease incidence in the field was well fitted by a Gompertz curve with an adjusted r2 of >0·99. Conidia of A. brassicicola were trapped in the field throughout the growing season. Peaks of high spore concentrations were usually associated with dry days, shortly after rain, high temperature or high wind speed. Diurnal periodicity of spore dispersal showed a peak of conidia trapped around 10·00 h. The number of conidia trapped at a height of 25 cm above ground level was greater than that at 50, 75 and 100 cm. Conidial dispersal was also studied under simulated conditions in a wind tunnel and a rain simulator. Generalized linear models were used to model these data. The number of conidia caught increased significantly at higher wind speeds and at higher rain intensities. Under simulated wind conditions, the number of conidia dispersed from source plants with wet leaves was only 22% of that for plants with dry leaves. Linear relationships were found between the number of conidia caught and the degree of infection of trap plants. [source] Vectoring of Pepino mosaic virus by bumble-bees in tomato greenhousesANNALS OF APPLIED BIOLOGY, Issue 2 2008J.L. Shipp Abstract Pepino mosaic virus (PepMV) has become an important viral disease of greenhouse tomatoes worldwide. The ability of bumble-bees (Bombus impatiens), used for pollination, to acquire and transmit PepMV was investigated, and the prevalence of PepMV in plants and bumble-bees in commercial tomato greenhouses was determined. PepMV infection in plants was determined using enzyme-linked immunosorbent assay, while in bumble-bees direct real-time PCR was used. In the first experiment, the bumble-bees were exposed for 14 days to PepMV-infected plants. After 14 days, almost all bumble-bees were PepMV positive both in the hive (78.5 ± 17.5%) and in the flowers (96.3 ± 3.6%). In the second experiment, bumble-bees were released into a greenhouse with both PepMV-infected source plants and healthy non-infected target plants for 14 days. At the end of the experiment, 61.0 ± 19.5% of the bees collected from the hive and 83.3 ± 16.7% of the bees sampled from the flowers were PepMV positive. Bumble-bees transmitted PepMV from the infected to the healthy non-infected tomato plants. Two weeks after bumble-bee release, the virus was detected in leaf, fruit and flower samples of formerly healthy plants. After 6 weeks, the percentage of PepMV positive samples from the target plants increased to 52.8 ± 2.8% of the leaves and 80.6 ± 8.4% of the fruits. In the control greenhouse without bumble-bees, the target plants did not become infected. Based on the infection levels in flowers, fruits and leaves, the PepMV infection occurred possibly first in the pollinated flowers, and then spread from the fruit that developed from the flowers to other parts of the plant. In commercial greenhouses where PepMV was present, 92,100% of the plants and 88,100% of the bumble-bees were PepMV positive. No infected plant samples were found in the control commercial greenhouse, but a small number of bumble-bees (10%) tested PepMV positive. [source] | ||||||||||