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Toxic effects of aluminium (Al) on root tips are considered to decrease export of cytokinins to shoots, and deficiency of cytokinins has been made responsible for Al‐induced inhibition of shoot growth. But no experimental data on the influence of Al on endogenous cytokinin levels in higher plants have been reported. In this study, the endogenous levels of zeatin riboside (ZR) and dihydrozeatin riboside (DHZR) of roots, stems, and leaves of two bean cultivars (Phaseolus vulgaris L. cv Contender and cv Strike) exposed to Al in continuously flowing nutrient solution (pH 4.5) was analysed. The supply of a high Al concentration (sum of monomeric Al species, 127 μM) caused severe inhibition of root elongation in both cultivars. The cv Strike was more affected by both Al‐induced mineral nutrient disorders and Al‐induced alteration of leaf water relationships. In both cultivars Al‐supply significantly increased ZR and DHZR. Leaves of Al‐treated plants exhibited a more than three times higher concentration of ribosylated cytokinins than controls. Nevertheless, stomatal resistance was significantly increased by Al in both cultivars. Our results support the hypothesis that Al affects plants not by inducing deficiency of cytokinins but of some other factor necessary for the manifestation of cytokinin action. 相似文献
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Bennassar A. Vazquez M. D. Cabot C. Poschenrieder Ch. Barcelo J. 《Water, air, and soil pollution》1991,(1):681-689
The influence of light intensity on the effects of 10–6 mol L–1
99Tc on growth, chlorophyll and carotenoid contents of bush bean plants was investigated. After germination and cotyledon excision, the plants were grown in a growth chamber either under low light (photosynthetic active radiation, PAR 144 E m–2 s–1) or higher light (PAR 307 E M–2 s–1) conditions. In plants grown under the higher light conditions, 99Tc hardly affected CO2-assimilation, dark respiration, pigment contents and growth. No toxicity symptoms were observed in these plants. Under low light conditions, 99T c significantly decreased growth and the concentration of chlorophylls. Toxicity symptoms in the form of chlorosis and necrosis developed. Transmission electron microscopy (TEM) observations revealed alterations of chloroplast ultrastructure comparable to those described for plants slightly affected by paraquat toxicity or by Mo-deficiency. Our results indicate that in the low light plants 99Tc induces damage in chloroplasts by peroxidation of membrane lipids. 相似文献
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Improving the end use properties of wheat by manipulating the grain protein composition 总被引：4，自引：0，他引：4
The wheat storage proteins account for up to about 60% of the totalgrain proteins. They correspond to the gluten proteins, which form avisco-elastic network that enables dough to be processed into bread, pastaand other products. We are using a range of biochemical, biophysical andmolecular approaches to characterize gluten proteins and to understandtheir role in determining the grain processing properties, focusing on thehigh molecular weight (HMW) subunits of glutenin which are majordeterminants of dough strength. We are also using genetic engineering toexplore the mechanism of glutenin elasticity and to effect improvements,by inserting genes encoding mutant and wild type HMW subunits intomodel lines and commercial cultivars. 相似文献
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Leonie Rooke Susan H. Steele Pilar Barcelo Peter R. Shewry Paul A. Lazzeri 《Euphytica》2003,129(3):301-309
Transgene integration, inheritance and expression were studied in six transgenic wheat (Triticum aestivum) lines produced by co-bombardment with two plasmids containing marker genes and genes encoding HMW subunits of wheat glutenin,
respectively. Transgene insertion number ranged from 1 to approximately 15. Within a transgenic locus the majority of plasmid
copies were found at dispersed genomic sites separated by intervening DNA. However, evidence was obtained for the arrangement
of introduced plasmid copies as concatamers and for plasmid truncation and rearrangement. Transgenes were frequently located
in genetically unlinked chromosome sites, resulting in independent segregation of loci among progeny. In two lines this gave
rise to progeny containing only the gene of interest. Transgenes were inherited in the T1 generation as a dominant trait although Mendelian segregation ratios were not always observed. No evidence of co-suppression
of
endogenous HMW subunits was observed.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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Marcelo Rodríguez‐Pin Daniela Casuriaga Patricia Genovese Gonzalo García‐Barcelo Fernanda Alcaide Alejandro Bielli 《Anatomia, histologia, embryologia》2019,48(4):306-314
The tortuous nature of the ovine cervix restricts the transcervical passage of the cannula, and many studies have aimed to understand the endocrine mechanism of the remodelling of cervical tissue in adult ewe. However, little is known about the remodelling of the cervical tissue during the prepubertal development of the lambs. To obtain histochemical and biochemical evidence about the nature of the prepubertal development of the cervix of the ewe, cervices of Corriedale lambs obtained at 0, 1, 2, 4, 6 and 8 months of age (n = 5 to 6 in each) were processed. Neutral and acidic glycosaminoglycans (by PAS‐Alcian stain) were weakly in the cervical stroma and not shown change during the development, whereas the percentage volume of fibrillar collagen (by van Gieson stain) increases throughout the experimental period in the superficial fold stroma and deep wall stroma (p < 0.05). The relative cervical weight (g/kg of body weight) and the collagen concentration (by spectrophotometry, mg/mg wet tissue) showed an early decreasing phase from months 0 to 4 and a later increasing phase from months 4 to 8 (p < 0.05). The latent form of matrix metalloproteinase‐2 (MMP‐2) detected by gelatin zymography (ng/mg protein) decreased from months 0 to 2 and increased from months 4 to 8, whereas the activated form decreased from months 0 to 2, remained low until month 6 and then recovered on month 8 (p < 0.0001). Data suggest that the relative cervical weight biphasic pattern during the development is related to MMP‐2‐dependent changes in the collagen content. 相似文献
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Eradications as scientific experiments: progress in simultaneous eradications of two major invasive taxa from a Mediterranean island 
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下载免费PDF全文 Lise Ruffino Elise Krebs Aurélie Passetti Annie Aboucaya Laurence Affre Damien Fourcy Olivier Lorvelec Alain Barcelo Laurence Berville Nathalie Bigeard Lenka Brousset Hélène De Méringo Pascal Gillet Patricia Le Quilliec Yannick Limouzin Frédéric Médail Jean‐Yves Meunier Marine Pascal Michel Pascal Philippe Ponel François Rifflet Coralie Santelli Elise Buisson Eric Vidal 《Pest management science》2015,71(2):189-198
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Bush beans (Phaseolus vulgaris L. cv Contender) were grown on perlite with nutrient solution and 0, 1, 2.5 and 5 ppm levels of Na2CrO4 Significant decrease of top growth and chlorosis in trifoliated leaves were observed for 2.5 and 5 ppm Cr, with Cr concentrations (μg/g) in tops:≥ 12.1, in roots:≥ 509.9. Cr decreased K, Na, Mg and Fe concentrations, and increased P and Mn concentrations in roots. In tops decreased N, K, Na and Fe concentrations and increased Mn and Ca concentrations were observed, Translocation of P, Zn, Cu and Fe was inhibited; Ca and Mn translocation was generally enhanced. P/Fe ratio was increased up to 60% in chlorotic plants, indicating a shift from Fe2+ to Fe3+. 相似文献
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The influence of a growth stimulating low Cr III concentration (1.0 μM) on chloroplast ultrastructure, the Fe, Cr, and Mn content of chloroplast extracts, o‐phenantroline extractable leaf Fe, and catalase activity was studied in both Fe‐sufficient and Fe‐deficient bush bean (Phaseolus vulgaris L.) plants. Chromium supply hardly affected the chloroplast ultrastructure of Fe‐sufficient plants but significantly improved chloroplast ultrastructure in Fe‐deficient leaves. Generally, Cr supply did not significantly influence chloroplast Fe‐content, but increased the Fe/Mn ratio in Fe‐deficient chloroplasts. In leaves from Fe‐deficient plants, o‐phenantroline extractable Fe was significantly increased, while catalase activity was not significantly influenced by Cr supply. The possible mechanisms of the beneficial effects of Cr III in Fe‐deficient plants are discussed. 相似文献
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