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Francisco J. Romera Esteban Alcántara Manuel Díaz de la Guardia 《Physiologia plantarum》1997,101(1):143-148
The effect of bicarbonate and selected metal ions on the development of enhanced root Fe(III) reducing capacity (a response to Fe deficiency of dicotyledons) was studied in young plants of cucumber ( Cucumis sativus L. cv. Ashley) grown in nutrient solution. Pretreatment of 11-day-old Fe-deficient cucumber plants with 20 m M NaHCO3 , for at least 23 h prior to determination of root Fe(III) reducing capacity, markedly inhibited this response. The inhibitory effect of bicarbonate could be partly reversed by a 4- to 8-h treatment with either 10 μ M MnSO4 , 10 μ M FeEDDHA, 2 μ M ZnSO4 , 0.5 μ M NiCl2 , or 0.25 μ M , or CoSO4 (final concentrations), added to the nutrient solution. By contrast, the addition of other salts of metal ions, like CuSO4 and Cd(NO3 )2 , at 0.25, 0.5 or 1 μ M , or MgSO4 , at 0.5, 1 or 2 m M (final concentrations), had no beneficial effect. The results suggest that bicarbonate may inhibit the development of root Fe(III) reducing capacity by diminishing the availability of certain metal ions required for this response. 相似文献
755.
The herbicides diuron, fluridone, or sulcotrione differently reduced chlorophyll (Chl) and carotenoid (Car) contents. Four days after herbicide treatment, application of sulcotrione resulted in a Chl/Car ratio of 5.88, similar as in untreated controls; diuron resulted in ratio of 5.24, while fluridone induced a greater diminution in Car contents and yielded a final ratio of 7.02. Sulcotrione induced a more rapid decrease than fluridone did in the quantum yield of photosystem 2 (PS2) as monitored by Chl fluorescence. Measurements of DPIP reduction with isolated thylakoids indicated that sulcotrione was a more effective inhibitor of the Hill reaction in cucumber, a herbicide sensitive species, than in maize, a herbicide-insensitive species. These results are consistent with the view that inhibition of electron transport via reduction in plastoquinone contents in plants leads to the major herbicidal effect of sulcotrione in mature green tissues. 相似文献
756.
757.
Barbara Politycka 《Acta Physiologiae Plantarum》1997,19(3):311-317
Seven-day-old seedlings of cucumber (Cucumis sativus L.) cv. Wisconsin were treated with 0.01, 0.1 and 0.5 mM solutions of derivatives of cinnamic acid (ferulic and p-coumaric acids)
and benzoic acid (p-hydroxybenzoic and vanillic acids) as stress factors. In cucumber roots phenolics (free and glucosylated),
phenol β-glucosyltransferase (E.C. 2.4.1.35) activity as well as membrane permeability were examined. The most intensive glucosylation
took place in the first hour of stress duration in roots treated with 0.01 mM ferulic and p-coumaric acids and with 0.01 and
0.1 mM p-hydroxybenzoic and vanillic acids. At these concentrations a high phenol β-glucosyltransferase activity was found.
The deterioration of capacity for phenolic glucosylation as well as the decrease of the phenol β-glucosyltransferase was observed
at the higher concentrations. It was associated with increased membrane permeability. 相似文献
758.
In a plastid-free assay, Mg-chelatase from pea ( Pisum sativum L. cv. Spring) and cucumber ( Cucumis sativus L. cv. Sumter) chloroplasts is inhibited to equal extents by the mercurial reagents. p -chloromercuribenzoate (PCMB) and p -chloromercuribenzene sulfonate (PCMBS). However, in intact chloroplasts PCMB inhibits Mg-chelatase fourfold more strongly than does PCMBS. Since PCMBS cannot penetrate membranes as readily as PCMB, Mg-chelatase may be localized interior to the inner chloroplast envelope. When Mg-chelatase is assayed with photosynthetically generated ATP, the presence of an external ATP trap does not inhibit activity, suggesting that the enzyme is not located in the interenvelope space. None of the components of Mg-chelatase are integral membrane proteins: Mg-chelatase activity is readily solubilized by washing the total chloroplast membranes in buffers of low MgCl2 content. This precludes localization by purifying individual thylakoid and envelope membranes which requires low MgCl2 concentrations. 相似文献
759.
Influence of silver nitrate (ethylene inhibitor) on cucumber in vitro shoot regeneration 总被引:6,自引:0,他引:6
Mohiuddin A.K.M. Chowdhury M.K.U. Abdullah Zaliha C. Napis Suhaimi 《Plant Cell, Tissue and Organ Culture》1997,51(1):75-78
The effect of addition of silver nitrate (AgNO3) on organogenesis of proximal and distal cotyledon and hypocotyl explants of five cucumber (Cucumis sativus L.) cultivars
was investigated. Distal cotyledon and hypocotyl were unresponsive while only poor shoot regeneration was observed in proximal
cotyledon and hypocotyl explants of all cucumber cultivars. The addition of different concentrations of AgNO3 (10, 30 and 50 μM) to the medium, however, induced shoot regeneration in distal cotyledon except Suyo Long cultivar and effectively
increased shoot regeneration response as well as the number of shoots per explant in proximal cotyledon and hypocotyl of all
cucumber cultivars.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
760.
Laura L. Georgi 《Journal of nematology》1988,20(3):474-477
A taxonomic revision of the Xiphinema americanum species complex has necessitated a reexamination of the host range of species in the complex before recommendations can be made with confidence on the likelihood that specific crops will be damaged. Toward this end, populations of X. americanum and X. rivesi collected from apple orchards in eastern and western New York state were evaluated after 3 months in pots planted with cucumber, apple, or dandelion seedlings. Eastern and western New York populations of both nematode species declined on cucumber but increased to similar final densities on apple and dandelion. 相似文献