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Allelopathy refers to plant-plant interference mediated mostly by plant released products of secondary metabolism. It was recently suggested that allelochamicals may influence growth of neighboring plants by induction of oxidative stress. We have focused on the role of reactive oxygen species (ROS) and phytohormons (ABA and ethylene) in the biochemical and molecular regulation of plant response to sunflower phytotoxins.Key Words: ABA, allelopathy, ethylene, H2O2, reactive oxygen species, seed germination 相似文献
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451 rural children (group I) and 2000 urban children (group II) aged 10-16 years from Toruń province were inquired by a questionnaire to their parents or guardians. 9.09% of children in the country and 13.45% of those living in the city of Toruń suffered from hypersensitivity disorders; bronchial asthma was reported in 2.22% and 3.05% of cases, allergic rhinitis--in 3.77% and 7.15%, allergic conjunctivitis--in 1.33% and 2.75%, allergic edema--in 0.44% and 0.60%, urticaria--in 1.55% and 3.50%, and infantile eczema--in 0.44% and 2.10% of cases, respectively. The pollinosis prevalence rate was 2.00% in group I and 1.85% in group II. At least 2 various forms of hypersensitivity coexisted in 30.48% of allergic urban children (64.86% of patients with pollinosis among them); infantile eczema preceded allergic rhinitis and bronchial asthma symptoms in 6.29% and 11.47% of cases, respectively, while allergic rhinitis occurred before the onset of bronchial asthma in 24.59% of asthmatic children. 37.10% of individuals with positive family history of allergic conditions also fell ill with some diseases of this nature, while in those with negative family history allergy occurred only in 10.22% of cases. From environmental factors mother's diseases during pregnancy, bottle feeding and a regular diet during the first year of life, frequent respiratory infections in the early childhood and poor living conditions increased the risk of allergic diseases or aggravated their course in the population examined. 相似文献
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Breaking the apple embryo dormancy by nitric oxide involves the stimulation of ethylene production 总被引:4,自引:0,他引:4
Mature seeds of apple (Mallus domestica Borb. cv. Antonówka) are dormant and do not germinate unless their dormancy is removed by several weeks of moist-cold treatment.
We investigated the effect of short-term (3 h) nitric oxide (NO) pretreatment on breaking of apple embryonic dormancy expressed
as inhibition of germination and morphological abnormalities of young seedlings. Imbibition of embryos isolated from dormant
apple seeds with sodium nitroprusside (SNP) or S-nitroso,N-acetyl penicillamine (SNAP) as NO donors resulted in enhanced germination. Moreover, NO treatment removed morphological abnormalities
of seedlings developing from dormant embryo. The NO scavenger 2-(4-carboxyphenyl)-4,4,5,5-teramethylimidazoline-1-oxyl-3 oxide
(cPTIO) removed the above effects. NO-mediated breaking of embryonic dormancy correlated well with enhanced ethylene production.
Inhibitor of ethylene synthesis (AOA) reversed the stimulatory effect of NO donors on embryo germination. Additionally SNP
reduced embryo sensitivity to exogenously applied ABA ensuing dormancy breakage. We can conclude that NO acts as a regulatory
factor included in the control of apple embryonic dormancy breakage by stimulation of ethylene biosynthesis. 相似文献
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Soltys D Rudzińska-Langwald A Kurek W Gniazdowska A Sliwinska E Bogatek R 《Planta》2011,234(3):609-621
Cyanamide is an allelochemical produced by hairy vetch (Vicia villosa Roth.). Its phyotoxic effect on plant growth was examined on roots of onion (Allium cepa L.) bulbs. Water solution of cyanamide (2-10 mM) restricted growth of onion roots in a dose-dependent manner. Treatment of onion roots with cyanamide resulted in a decrease in root growth rate accompanied by a decrease in accumulation of fresh and dry weight. The inhibitory effect of cyanamide was reversed by its removal from the environment, but full recovery was observed only for tissue treated with this chemical at low concentration (2-6 mM). Cytological observations of root tip cells suggest that disturbances in cell division may explain the strong cyanamide allelopathic activity. Moreover, in cyanamide-treated onion the following changes were detected: reduction of mitotic cells, inhibition of proliferation of meristematic cells and cell cycle, and modifications of cytoskeleton arrangement. 相似文献
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Allelopathy is defined as mechanism of plant-plant, plant-microorganisms, plant-virus, plant-insect, and plant-soil-plant
interactions mediated by plant- or microorganism-produced chemicals released to the environment. The majority of allelochemicals
are secondary metabolites and among others belong to terpenoids, phenolic compounds, organic cyanides and longchain fatty
acids. The action of allelochemicals in target plant is diverse and affects a large number of biochemical reactions resulting
in modifications of different physiological functions. Thus the results of allelochemical action can be detected at different
levels of plant organization: molecular, structural, biochemical, physiological and ecological. Enzyme activities, cell division
and ultrastructure, membrane permeability, ion uptake and as a consequence plant growth and development are modified by allelochemicals.
Significant effects on photosynthesis and respiration are the best-characterized results of allelopathic interactions. Moreover
allelopathic compounds seem to induce a secondary oxidative stress expressed as enhanced free radical production and induction
of cellular antioxidant system. Plant survival under allelopathy stress conditions depends on plant defense leading to allelochemical
detoxication, the process which may go on in parallel to cell defense reaction to oxidative stress.
The article presents some aspects of the current knowledge regarding mechanisms of the allelopathy phenomenon. The allelopathy
is a complex problem, thus comprehensive understanding of allelochemical mode of action requires further investigation and
still remains an open question. 相似文献
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Agnieszka Gniazdowska Urszula Krasuska Karolina Dębska Paulina Andryka Renata Bogatek 《Planta》2010,232(4):999-1005
Deep dormancy of apple (Malus domestica Borkh.) seeds is terminated by a 3-month-long cold stratification. It is expressed by rapid germination of seeds and undisturbed
growth of seedlings. However, stimulation of germination of isolated apple embryos is also observed after applying inhibitors
of cytochrome c oxidase: nitric oxide (NO) or hydrogen cyanide (HCN) during the first 3–6 h of imbibition of dormant embryos. The aim of
this work was to compare the effect of yet another toxic gaseous molecule carbon monoxide (CO) with the effects of HCN and
NO on germination of apple embryos and growth and development of young seedlings. We demonstrated that stimulation of germination
after short-term pre-treatment with HCN, NO or CO was accompanied by enhanced NO emission from the embryo axes during their
elongation. Moreover, similarly high NO production from non-dormant embryos, after cold stratification, was detected. Therefore,
we propose that NO may act as signaling molecule in apple embryo dormancy break. 相似文献
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