Physiologia Plantarum
0031-9317
1399-3054
Anh Quốc
Cơ quản chủ quản: Wiley-Blackwell Publishing Ltd , WILEY
Lĩnh vực:
Cell BiologyPlant ScienceMedicine (miscellaneous)PhysiologyGenetics
Các bài báo tiêu biểu
A Revised Medium for Rapid Growth and Bio Assays with Tobacco Tissue Cultures
Tập 15 Số 3 - Trang 473-497 - 1962
Ascorbate peroxidase – a hydrogen peroxide‐scavenging enzyme in plants Ascorbate peroxidase is a hydrogen peroxide‐scavenging enzyme that is specific to plants and algae and is indispensable to protect chloroplasts and other cell constituents from damage by hydrogen peroxide and hydroxyl radicals produced from it. In this review, first, the participation of ascorbate peroxidase in the scavenging of hydrogen peroxide in chloroplasts is briefly described. Subsequently, the phylogenic distribution of ascorbate peroxidase in relation to other hydrogen peroxide‐scavenging peroxidases using glutathione, NADH and cytochrome c is summarized. Chloroplastic and cytosolic isozymes of ascorbate peroxidase have been found, and show some differences in enzymatic properties. The basic properties of ascorbate peroxidases, however, are very different from those of the guaiacol peroxidases so far isolated from plant tissues. Amino acid sequence and other molecular properties indicate that ascorbate peroxidase resembles cytochrome c peroxidase from fungi rather than guaiacol peroxidase from plants, and it is proposed that the plant and yeast hydrogen peroxide‐scavenging peroxidases have the same ancestor.
Tập 85 Số 2 - Trang 235-241 - 1992
Hydrogen peroxide‐ and glutathione‐associated mechanisms of acclimatory stress tolerance and signalling Plants adapt to environmental stresses through specific genetic responses. The molecular mechanisms associated with signal transduction, leading to changes in gene expression early in the stress response, are largely unknown. It is clear, however, that gene expression associated with acclimatory responses is sensitive to the redox state of the cell. Of the many components which contribute to the redox balance of the cell, two factors have been shown to be crucial in mediating stress responses. Thiol/disulphide exchange reactions, particularly involving the glutathione pool and the generation of the oxidant H2 O2 , are central components of signal transduction in both environmental and biotic stresses. These molecules are multifunctional triggers, modulating metabolism and gene expression. Both are able to cross biological membranes and diffuse or be transported long distances from their sites of origin. Glutathione and H2 O2 may act alone or in unison, in intracellular and systemic signalling systems, to achieve acclimation and tolerance to biotic and abiotic stresses.
Tập 100 Số 2 - Trang 241-254 - 1997
Water stress induced changes in concentrations of proline and total soluble sugars in nodulated alfalfa (<i>Medicago sativa</i>) plants Susceptibility of alfalfa (Medicago sativa L. cv. Aragón) nodules and leaves to water stress has been investigated. Nodule acetylene reduction activity (ARA), leaf CO2 exchange rate (CER) as well as soluble protein, proline and total soluble sugar (TSS) contents were determined during drought. Water status was estimated as water potential (Ψw ) and Relative water content (RWC) of the respective tissues. Maximum rates of ARA required higher Ψw than CER. Nodules had lower RWC for a given Ψw than leaves. Water stress reduced soluble protein content in both tissues; however, the decline in soluble protein content was detected at greater Ψw in nodules than in leaves. Proline and TSS increased in leaves and nodules, and again the threshold Ψw triggering such accumulation was higher in nodule tissues. Oior results suggest that alfalfa nodules are more susceptible to water shortage than leaves. Effects of accumulated TSS and proline upon leaf and nodule physiology are discussed in relation to protein stability (proline), pH control (proline) and osmotic adjustment (proiine and TSS). The TSS accumulation induced by water stress suggests that substrate shortage would not be the primary effect of drought on nodule activity.
Tập 84 Số 1 - Trang 55-60 - 1992
Non‐destructive optical detection of pigment changes during leaf senescence and fruit ripening Reflectance spectra in the visible and near infra‐red range of the spectrum, acquired for maple (Acer platanoides L.), chestnut (Aesculus hippocastanum L.), potato (Solanum tuberosum L.), coleus (Coleus blumei Benth.), leaves and lemon (Citrus limon L.) and apple (Malus domestica Borkh.) fruits were studied. An increase of reflectance between 550 and 740 nm accompanied senescence‐induced degradation of chlorophyll (Chl), whereas in the range 400–500 nm it remained low, due to retention of carotenoids (Car). It was found that both leaf senescence and fruit ripening affect the difference between reflectance (R ) near 670 and 500 nm (R 678 −R 500 ), depending on pigment composition. The plant senescing reflectance index in the form (R 678 −R 500 )/R 750 was found to be sensitive to the Car/Chl ratio, and was used as a quantitative measure of leaf senescence and fruit ripening. The changes in the index were followed during leaf senescence, and natural and ethylene‐induced fruit ripening. This novel index can be used for estimating the onset, the stage, relative rates and kinetics of senescence/ripening processes.
Tập 106 Số 1 - Trang 135-141 - 1999
The isolation and characterization of abscisic acid‐insensitive mutants of <i>Arabidopsis thaliana</i> Abscisic acid (ABA) insensitive mutants of Arabidopsis thaliana (L.) Heynh. were isolated by selecting plants which grew well on a medium containing 10 μM ABA. From the progeny of approximately 3500 mutagen‐treated seeds, five mutants of at least three different loci were isolated. Three mutants were characterized, moreover, by a reduced seed dormancy and by symptoms of withering, indicating disturbed water relations and, therefore, resembled phenotypically the ABA‐deficient mutants we described earlier in this species. Two mutants showed in addition only a reduction of seed dormancy. Compared to wild type, all mutants showed similar or increased levels of endogenous ABA in developing seeds and fruits (siliquae). The role of the different genes involved is discussed in relation to the mechanism of ABA action.
Tập 61 Số 3 - Trang 377-383 - 1984
Reactive oxygen species and antioxidants: Relationships in green cells The imposition of oxidative stress leads to increased production of reactive oxygen species (ROS) in plant cells. Orchestrated defense processes ensue that have much in common between stresses, yet are also particular to the site of action of the stress and its concentration. Possible functional roles of these responses include, but are not restricted to, the protection of the photosynthetic machinery, the preservation of membrane integrity and the protection of DNA and proteins. Superimposed upon our understanding of cellular mechanisms for protection against abiotic stress is a newly discovered role of ROS in signalling and defense response to pathogens (J. L. Dangl, R. A. Dietrich and M. S. Richberg. 1996. Plant Cell 8: 1793–1807). Evidence to date suggests a coordinated response to ROS among different members of the superoxide dismutase (SOD) gene families. A further layer of complexity is afforded by reports of coordination of expression between ascorbate peroxidase and SOD genes. Our understanding of the signalling mechanisms that underlie these coordinated events is in its infancy. An exciting future lies ahead in which the orchestration of successful antioxidant stress responses will be gradually revealed. Current data suggest that complex regulatory mechanisms function at both the gene and protein level to coordinate antioxidant responses and that a critical role is played by organellar localization and inter‐compartment coordination.
Tập 100 Số 2 - Trang 224-233 - 1997
The light‐harvesting and protective functions of carotenoids in photosynthetic membranes Siefermann‐Harms, D. 1987. The light‐harvesting and protective functions of carotenoids in photosynthetic membranes.
Tập 69 Số 3 - Trang 561-568 - 1987
The plant‐growth‐promoting rhizobacteria <i>Bacillus pumilus</i> and <i>Bacillus licheniformis</i> produce high amounts of physiologically active gibberellins The plant‐growth‐promoting rhizobacteria (PGPR), Bacillus pumilus and Bacillus licheniformis, isolated from the rhizosphere of alder (Alnus glutinosa [L.] Gaertn.) have a strong growth‐promoting activity. Bioassay data showed that the dwarf phenotype induced in alder seedlings by paclobutrazol (an inhibitor of gibberellin [GA] biosynthesis) was effectively reversed by applications of extracts from media incubated with both bacteria and also by exogenous GA3 . Full‐scan gas chromatography‐mass spectrometry analyses on extracts of these media showed the presence of GA1 , GA3 , GA4 and GA20 , in addition to the isomers 3‐epi ‐GA1 and iso ‐GA3 . Isotope dilution analysis indicated that epi ‐GA1 was an artefact. Likewise, iso ‐GA3 is also probably an artifact spontaneously formed during extraction and/or analysis. In both culture media, GA1 was present in higher concentrations (130–150 ng ml−1 ) than GA3 (50–60 ng ml−1 ), GA4 (8–12 ng ml−1 ) and GA20 (2–3 ng ml−1 ). The data indicated that culture of both bacteria accumulate bioactive C19‐gibberellins in relative high amounts and that these GAs appear to be physiologically active in the host plant. The evidence suggests that the promotion of stem elongation induced by the PGPR could be mediated by bacterial GAs.
Tập 111 Số 2 - Trang 206-211 - 2001