8,787 research outputs found

    Collembola Permukaan Tanah pada Lahan Sayuran Cruciferae Didesa Serang, Kabupaten Purbalingga

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    Collembola are one of the ecosystem components that are important in keeping the ecosystem stability. Beside its role as the decomposer, Collembola also takes part as the alternative foods for arthropod predators. This research was aimed to know the diversity and abundance of Collembola top soil on land area of Cruciferae in agrotourism and in the edge of the forest in Serang, Purbalingga, Central Java. The sampling was done using pitfall trap. The results showed that the abundance of Collembola on land area of Cruciferae in the edge of the forest is higher than on land area of Cruciferae in agrotourism, but the diversity of Collembola in agrotorism was not different from that of in the edge of the forest. Hypogastruridae was the family with the highest abundance on land area of Cruciferae in the edge of the forest, while Entomobryidae was the family with the highest abundance on land area of Cruciferae in agrotouris

    The Analysis and Interpretation of Seedling Recruitment Curves

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    We derive spatially explicit population models for the interaction between a species of annual plant and a community of perennial species. The models are used to explore the conditions for persistence of the annual in both a constant and a stochastic environment. In both types of environment a seed's response to the presence of established perennial plants is found to affect strongly the conditions for persistence. Sensitivity analysis of a parameterized version of the model indicates the importance of germination and mortality parameters in allowing persistence. In the parameterized model large changes in fecundity have little effect on the condition for persistence. The implications of these results for the distribution of annual plants and the forces structuring communities of short-lived plants in successional habitats are discussed

    The Analysis and Interpretation of Seedling Recruitment Curves

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    We derive spatially explicit population models for the interaction between a species of annual plant and a community of perennial species. The models are used to explore the conditions for persistence of the annual in both a constant and a stochastic environment. In both types of environment a seed's response to the presence of established perennial plants is found to affect strongly the conditions for persistence. Sensitivity analysis of a parameterized version of the model indicates the importance of germination and mortality parameters in allowing persistence. In the parameterized model large changes in fecundity have little effect on the condition for persistence. The implications of these results for the distribution of annual plants and the forces structuring communities of short-lived plants in successional habitats are discussed

    2013 REU Poster: Modulation of Indolic Plant Defense compound Synthesis by Tryptophan Analogs

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    Poster presentation at REU Summer's End Research Symposium, 2013, by REU participant Marie Prisca Sanon, Massasoit Community College - John "Chip" Celenza group, Sanda Zolj lab mentorLike bacteria and fungi, plants are able to synthesize aromatic amino acids Tyrosine (Tyr), Phenylalanine (Phe) and Tryptophan (Trp). Those amino acids are used in plants not only for protein synthesis, but also for a variety of compounds that control development and defense. Arabidopsis thaliana uses Trp to produce distinct secondary metabolites that function as deterrents to herbivory (indole glucosinolates), as defense against microbial pathogens (camalexin) and as growth regulators(indole-3-acetic acid). To better understand the relationship between Trp biosynthesis and indole glucosinolate (IGs) production, we have tested different analogs of Trp on Columbia, a wild-type Arabidopsis accession. We have found that alpha-methyl tryptophan cannot be incorporated into IGs and in fact inhibits IG synthesis.NSF-RE

    Laboratory Studies of the Activity of Spinosad against Leptinotarsa decemlineata (Say) Depending on Different Temperature

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    Mortality of the Colorado potato beetle larvae (Say) and adults caused by commercial formulation of spinosad at 15, 20 and 250C was determined under laboratory conditions. The insects and the leaves of potatoes were sprayed with the insecticide. Thus, the insecticide was toxic by exposure to treated surfaces and ingestion. Three concentrations of insecticide were used: 0.2%, 0.1% and 0.05%. The effect was assessed the 6th day after treatment. All concentrations caused mortality both adults and larvae; however mortality of tested insect stages increased as concentration of spinosad increased. For adults was observed the highest mortality in combination with 0.2% at 150C, whereas at this same temperature in combination with 0.1% was reached the lowest mortality. In tests with the larvae was observed that 0.2% of spinosad caused the lowest mortality at 250C, whereas concentration 0.1% of spinosad reached the best results at this same temperature. For adults and larvae concentrations 0.05% of spinosad reached the lowest mortality and differences between results in this combination depend on temperature were not observed

    Burial and seed survival in Brassica napus subsp. oleifera and Sinapis arvensis including a comparison of transgenic and non-transgenic lines of the crop

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    The creation of transgenic plants through genetic engineering has focused interest on how the fitness of a plant species may be altered by small changes in its genome. This study concentrates on a key component of fitness: persistence of seeds overwinter. Seeds of three lines of oilseed rape (Brassica napus subsp. oleifera DC Metzger) and of charlock (Sinapis arvensis L.) were buried in nylon mesh bags at two depths in four habitats in each of three geographically separated sites: Cornwall, Berkshire and Sutherland. Seeds were recovered after 12 and 24 months. Charlock exhibited much greater seed survival (average 60 per cent surviving the first year and 32.5 per cent surviving the second year) than oilseed rape (1.5 per cent surviving the first year and 0.2 per cent surviving the second) at all sites. Charlock showed higher survival at 15 cm burial than 2 cm burial at certain sites, but oilseed rape showed no depth effect. Different genetic lines of oilseed rape displayed different rates of seed survival; non-transgenic rape showed greater survival (2 per cent) than the two transgenic lines, one developed for tolerance to the antibiotic kanamycin (0.3 per cent) and one for tolerance to both kanamycin and the herbicide glufosinate (0.25 per cent). The absolute and relative performances of the different genetic lines of oilseed rape were context specific, illustrating the need to test hypotheses in a wide range of ecological settings

    Turnip mosaic potyvirus probably first spread to Eurasian brassica crops from wild orchids about 1000 years ago

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    Turnip mosaic potyvirus (TuMV) is probably the most widespread and damaging virus that infects cultivated brassicas worldwide. Previous work has indicated that the virus originated in western Eurasia, with all of its closest relatives being viruses of monocotyledonous plants. Here we report that we have identified a sister lineage of TuMV-like potyviruses (TuMV-OM) from European orchids. The isolates of TuMV-OM form a monophyletic sister lineage to the brassica-infecting TuMVs (TuMV-BIs), and are nested within a clade of monocotyledon-infecting viruses. Extensive host-range tests showed that all of the TuMV-OMs are biologically similar to, but distinct from, TuMV-BIs and do not readily infect brassicas. We conclude that it is more likely that TuMV evolved from a TuMV-OM-like ancestor than the reverse. We did Bayesian coalescent analyses using a combination of novel and published sequence data from four TuMV genes [helper component-proteinase protein (HC-Pro), protein 3(P3), nuclear inclusion b protein (NIb), and coat protein (CP)]. Three genes (HC-Pro, P3, and NIb), but not the CP gene, gave results indicating that the TuMV-BI viruses diverged from TuMV-OMs around 1000 years ago. Only 150 years later, the four lineages of the present global population of TuMV-BIs diverged from one another. These dates are congruent with historical records of the spread of agriculture in Western Europe. From about 1200 years ago, there was a warming of the climate, and agriculture and the human population of the region greatly increased. Farming replaced woodlands, fostering viruses and aphid vectors that could invade the crops, which included several brassica cultivars and weeds. Later, starting 500 years ago, inter-continental maritime trade probably spread the TuMV-BIs to the remainder of the world

    Intraspecifle variability of lberispinnata L

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    VILLARRUBLÁ, M. J. & MORENO, M. 1993. Estudio de la variabilidad intraespecífica en Ibens pinnata L. (Cruciferae). Bot. Complutensis 18: 129-136 Se estudia la variabilidad intraespecífica de 1. pinnata. L. discutiendo la existencia de taxoBes infraespecíficos en su seno.VILLÁRUBIA, M. 1. & MORENO, M. 1993. Intraespecific variability in Iberis pinnata L. (Cruciferae). Bol. Complutensis ¡8: ¡29-136 It is studied tbe intraspecific variability of 1. pinnata L., discussing thc existence of infraspttcitic taxa

    Additions to the Known Endemic Flora and Fauna of Arkansas

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    Robison and Smith\u27s (1982) list of endemic species of Arkansas rendered a valuable service to the community of biologists interested in the endemic biota of the state. These authors listed seven species of plants and forty species of animals endemic to Arkansas. This paper stimulated my interest in the endemic biota of the Ozark/Ouachita Mountain region of Missouri, Arkansas, and Oklahoma. During the course of compiling a list of Ozark/Ouachita endemic species several references were found that listed Arkansas endemic taxa inadvertently overlooked by Robison and Smith. Most notable among these references was Chamberlin and Hoffman (1958), Checklist of the Millipeds of North America. This paper chronicles the work of N. B. Causey and R. V. Chamberlin who describe thirty-two species of endemic Arkansas Millipeds. These records as well as a few additional records for other animal and plant taxa are presented in this paper
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