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1.
Exogenous auxin and cytokinin dependent activation of CDKs and cell division in leaf protoplast-derived cells of alfalfa 总被引:4,自引:0,他引:4
T. Pasternak P. Miskolczi F. Ayaydin T. Mészáros D. Dudits A. Fehér 《Plant Growth Regulation》2000,32(2-3):129-141
Alfalfa leaf protoplast cultures were used to study the role ofexogenously supplied auxin and cytokinin on the level and activity ofCdc2-related protein kinases and progression through the first celldivision cycle after re-activation of cell division. Among the threealfalfa Cdc2-related kinases studied, the Cdc2MsA/B kinase (PSTAIRE)showed only significant activity during the first four days ofprotoplast culture while the Cdc2MsD (PPTALRE) and Cdc2MsF kinases(PPTTLRE) exhibited only low or undetectable activity, respectively,during this period. Although the Cdc2MsA/B protein could be detectedin leaves and freshly isolated protoplasts in variable amounts, thekinase was never active in these cells. The kinase protein disappearedfrom protoplast-derived cells at the beginning (8h) of culture but itssynthesis re-commenced dependent on the presence of exogenous auxin butnot cytokinin. The cytokinin response of alfalfa protoplast-derivedcells varied significantly in different experiments although cytokininwas always required for completion of the first cell division cycle.Frequently both auxin and cytokinin was required for DNA replication asnot more than 5% of cells could incorporate BrdU into their DNAduring three days and significant Cdc2MsA/B activity could not bedetected in the absence of exogenous cytokinin. In other protoplastpopulations, the Cdc2MsA/B kinase was activated by auxin alone andallowed the protoplast-derived cells to enther the S-phase at a similarrate observed in parallel cultures with both auxin and cytokinin. Evenin these cultures, however, ca. 95% of the protoplast-derivedcells were arrested before mitosis without exogenous cytokinin supplywhich could be correlated with decreasing Cdc2MsA/B activity. Theseobservations suggest, that although cytokinin is required for bothG0-G1/S and G2/M cell cycle transitions, in certain cultures theG1/S requirement is overcome by some unknown factors (e.g.conditions of explants; endogenous cytokinins etc.). Furthermore, ourexperiments indicate, that the roles of cytokinin are related to thepost-translational regulation of the Cdc2MsA/B kinase complex atboth cell cycle transition points in alfalfa leaf protoplast-derivedcells. Finally, as a marker for the transition from the differentiated(G0) stage to the activated (G1) stage, we suggest using the parametersof nuclear morphology (size and ratio ofnucleus/nucleolus). 相似文献
2.
The Role of auxin,pH, and stress in the activation of embryogenic cell division in leaf protoplast-derived cells of alfalfa 总被引:1,自引:0,他引:1 下载免费PDF全文
Pasternak TP Prinsen E Ayaydin F Miskolczi P Potters G Asard H Van Onckelen HA Dudits D Fehér A 《Plant physiology》2002,129(4):1807-1819
Culturing leaf protoplast-derived cells of the embryogenic alfalfa (Medicago sativa subsp. varia A2) genotype in the presence of low (1 microM) or high (10 microM) 2, 4-dichlorophenoxyacetic acid (2,4-D) concentrations results in different cell types. Cells exposed to high 2,4-D concentration remain small with dense cytoplasm and can develop into proembryogenic cell clusters, whereas protoplasts cultured at low auxin concentration elongate and subsequently die or form undifferentiated cell colonies. Fe stress applied at nonlethal concentrations (1 mM) in the presence of 1 microM 2,4-D also resulted in the development of the embryogenic cell type. Although cytoplasmic alkalinization was detected during cell activation of both types, embryogenic cells could be characterized by earlier cell division, a more alkalic vacuolar pH, and nonfunctional chloroplasts as compared with the elongated, nonembryogenic cells. Buffering of the 10 microM 2,4-D-containing culture medium by 10 mM 2-(N-morpholino)ethanesulfonic acid delayed cell division and resulted in nonembryogenic cell-type formation. The level of endogenous indoleacetic acid (IAA) increased transiently in all protoplast cultures during the first 4 to 5 d, but an earlier peak of IAA accumulation correlated with the earlier activation of the division cycle in embryogenic-type cells. However, this IAA peak could also be delayed by buffering of the medium pH by 2-(N-morpholino)ethanesulfonic acid. Based on the above data, we propose the involvement of stress responses, endogenous auxin synthesis, and the establishment of cellular pH gradients in the formation of the embryogenic cell type. 相似文献
3.
G. B. Pouisen G. Frugis M. Albrechtsen D. Mariotti 《Plant Cell, Tissue and Organ Culture》1996,44(3):257-260
Extracellular proteins, released into the culture medium from alfalfa cells grown in embryogenic and non-embryogenic conditions, were 35S-methionine labelled at different days of culture. SDS-PAGE analysis showed significant differences between the patterns of extracellular proteins secreted into the medium devoid of 2,4-d, in which cells formed somatic embryos, or in presence of 2,4-d, in which undifferentiated cell proliferation took place. Some proteins, evident in 2,4-d-supplied cultures, disappeared when cells were subcultured in the embryogenic conditions. Western analysis with antibodies against the carrot extracellular proteins EP1 and EP2 showed the presence of homologous alfalfa proteins. In 2,4-d depleted alfalfa cells, an EP1-like protein disappeared and another one was reduced, while the presence of the EP2-like protein was, in the same conditions, strongly enhanced.Abbreviations 2,4-d
2,4-dichlorophenoxyacetic acid
- EP
extracellular proteins
- ns-LTP
non specific lipid transfer protein
- SDS-PAGE
Sodium dodecyl sulphate polyacrilamide gel electrophoresis 相似文献
4.
We have monitored the changes in antioxidant enzyme activities and H2O2 concentrations in roots of rice (Oryza sativa L., cv. Taichung Native 1) seedlings treated with exogenous abscisic acid(ABA). Decrease in superoxide dismutase (SOD) and catalase (CAT) activities was observed in rice roots in the presence of ABA. However, ascorbate peroxide (APX) and glutathione reductase (GR) activities were increased after the ABA treatment. ABA treatment resulted in an increase in H2O2 concentrations in rice roots. Pre-treatment with dimethylthiourea, a chemical trap for H2O2, and diphenyleneiodonium chloride (DPI), a well known inhibitor of NADPH oxidase, inhibited ABA-induced accumulation of H2O2 and ABA-induced activities of APX and GR. ABA-induced accumulation of H2O2 was found to be prior to ABA-induced activities of APX and GR. Our results suggest that H2O2 is involved in ABA-induced APX and GR activities in rice roots. 相似文献
5.
Summary An optimum 10-day exposure of petioles of alfalfa [Medicago sativa ssp.falcata (L.) Arcangeli] to 2,4-dichlorophenoxyacetic acid or 2,4,5-trichlorophenoxyacetic acid results in the semisynchronous production
of somatic embryos starting about 4 days after transfer to a non-auxin-containing medium. The timing of cell division induction
in the petiole explants was found to vary depending on the petiole tissue type. Cells adjacent to the vascular bundles divide
first at about 48 h after exposure to auxin, closely followed by those of the inner parenchyma, whereas most of the cells
of the subepidermal and epidermal layers start to divide later, between 72 and 120 h. Two different sources of callus were
also evident. Cells adjacent to the vascular bundles and the inner parenchyma cells were the primary source of callus when
a short, 2-day (non-embryo-producing) exposure to auxin was used. In contrast, the subepidermal and epidermal cells were the
primary source of callus tissue when a longer, 10-day (embryo producing) exposure was used. It is concluded that the source
of somatic embryos is primarily the daughter cells of the subepidermal or epidermal tissue or both. 相似文献
6.
7.
An oxidative and salinity stress induced peroxisomal ascorbate peroxidase from Avicennia marina: Molecular and functional characterization 总被引:1,自引:0,他引:1
Kumaresan Kavitha Gayatri Venkataraman Ajay Parida 《Plant Physiology and Biochemistry》2008,46(8-9):794-804
APX (EC, 1.11.1.11) has a key role in scavenging ROS and in protecting cells against their toxic effects in algae and higher plants. A cDNA encoding a peroxisomal ascorbate peroxidase, Am-pAPX1, was isolated from salt stressed leaves of Avicennia marina (Forsk.) Vierh. by EST library screening and its expression in the context of various environmental stresses was investigated. Am-pAPX1 contains an ORF of 286 amino acids coding for a 31.4kDa protein. The C-terminal region of the Am-pAPX1 ORF has a putative transmembrane domain and a peroxisomal targeting signal (RKKMK), suggesting peroxisomal localization. The peroxisomal localization of Am-pAPX1 was confirmed by stable transformation of the GFP-(Ala)(10)-Am-pAPX1 fusion in tobacco. RNA blot analysis revealed that Am-pAPX1 is expressed in response to salinity (NaCl) and oxidative stress (high intensity light, hydrogen peroxide application and excess iron). The isolated genomic clone of Am-pAPX1 was found to contain nine exons. A fragment of 1616bp corresponding to the 5' upstream region of Am-pAPX1 was isolated by TAIL-PCR. In silico analysis of this sequence reveals the presence of putative light and abiotic stress regulatory elements. 相似文献
8.
Growth,sugar accumulation,and dark respiration of suspension cell cultures derived from contrasting alfalfa cultivars 总被引:1,自引:0,他引:1
Kalengamaliro N.E. Cunningham S.M. Volenec J.J. 《Plant Cell, Tissue and Organ Culture》2003,72(2):163-171
Fall dormancy results in decumbent, slow shoot growth of alfalfa (Medicago sativa L.) in autumn and reduced shoot regrowth rates after herbage removal in summer. Although fall dormancy is used to predict alfalfa adaptation, we possess a poor understanding of the biological mechanisms underlying fall dormancy. Our objective was to examine growth and carbohydrate metabolism of suspension cell cultures derived from contrasting alfalfa cultivars that genetically differed in fall dormancy. Suspension cells were grown in B5h media containing 2% sucrose. Cells derived from fall non-dormant plants accumulated sugars more rapidly after transfer to fresh media and to higher concentrations than did cells derived from fall dormant alfalfa cultivars. Dark respiration rates of cells derived from non-dormant plants were similar to those derived from fall dormant plants when growth was limited at low cell sugar concentrations. However, both cell growth and dark respiration rates increased in cells derived from non-dormant cultivars in response to greater cell sugar concentrations. High growth rates of cells derived from rapid growing, fall non-dormant alfalfa cultivars were associated with rapid sugar uptake and higher cell respiration rates when compared to cells derived from dormant alfalfa cultivars. 相似文献
9.
The accumulation of H2O2 by NaCl was observed in the roots of rice seedlings. Treatment with NaCl caused an increase in the activities of ascorbate peroxidase (APX) and glutathione reductase (GR) and the expression of OsAPX and OsGR in rice roots. Exogenously applied H2O2 also enhanced the activities of APX and GR and the expression of OsAPX and OsGR in rice roots. The accumulation of H2O2 in rice roots in response to NaCl was inhibited by the NADPH oxidase inhibitors, diphenyleneiodonium chloride (DPI) and imidazole (IMD). However, DPI, IMD, and dimethylthiourea, a H2O2 trap, did not reduce NaCl-enhanced activities of APX and GR and expression of OsAPX and OsGR. It appears that H2O2 is not involved in the regulation of NaCl-induced APX and GR activities and OsAPX and OsGR expression in rice roots. 相似文献
10.
Seedlings of rice (Oryza sativa L.) cv. Pant-12 grown in sand cultures containing 200 and 400 μM NiSO4, showed a decrease in length and fresh weight of roots and shoots. Nickel was readily taken up by rice seedlings and the
concentration was higher in roots than shoots. Nickel-treated seedlings showed increased rates of superoxide anion (O2
•−
) production, elevated levels of H2O2 and thiobarbituric acid reactive substances (TBARS) demonstrating enhanced lipid peroxidation, and a decline in protein thiol
levels indicative of increased protein oxidation compared to controls. With progressively higher Ni concentrations, non-protein
thiol and ascorbate (AsA) increased, whereas the level of low-molecular-weight thiols (such as glutathione and hydroxyl-methyl
glutathione), the ratio of these thiols to their corresponding disulphides, and the ratio of AsA to dehydroascorbic acid declined
in the seedlings. Among the antioxidant enzymes studied, the activities of all isoforms of superoxide dismutase (Cu-Zn SOD,
Mn SOD and Fe SOD), guaiacol peroxidases (GPX) and ascorbate peroxidase (APX) increased in Ni-treated seedlings, while no
clear alteration in catalase activity was evident. Activity of the ascorbate-glutathione cycle enzymes monodehydroascorbate
reductase (MDHAR), dehydroascorbate reductase (DHAR) and glutathione reductase (GR)—significantly increased in Ni-treated
seedlings. However such increase was apparently insufficient to maintain the intracellular redox balance. Results suggest
that Ni induces oxidative stress in rice plants, resulting in enhanced lipid peroxidation and decline in protein thiol levels,
and that (hydroxyl-methyl) glutathione and AsA in conjunction with Cu-Zn SOD, GPX and APX are involved in stress response. 相似文献
11.
Effect of exogenous hydrogen peroxide on enzymatic and nonenzymatic antioxidants in leaves of young pea plants treated with paraquat 总被引:1,自引:0,他引:1
Irina Moskova Dessislava Todorova Vera Alexieva Sergei Ivanov Iskren Sergiev 《Plant Growth Regulation》2009,57(2):193-202
The effects of exogenously applied hydrogen peroxide on the antioxidant system of pea plants were investigated. Ten-day-old
pea seedlings were sprayed with 2.5 mM H2O2 and 24 h later with 0.2 mM PQ. Samples were taken 0, 2 and 5 h after the start of illumination. The protective effect of
H2O2 was evaluated by monitoring of parameters related to the damage caused by PQ. The treatment with PQ led to a severe leakage
of electrolytes from leaf tissues. Malondialdehyde level increased in PQ treated plants, but remained unchanged in H2O2 pre-treated ones after 5 h of illumination. Increased catalase and glutathione-S-transferase activity was observed in pea
plants treated with H2O2 and PQ. Ascorbate peroxidase activity decreased significantly after paraquat application, but pre-treatment with H2O2 prevented ascorbate peroxidase inhibition to some extent. Increased guaiacol peroxidase activity was detected after H2O2 application. PQ application caused a drastic decline in the levels of thiol-group bearing compounds, reduced glutathione
and ascorbate, while the quantity of oxidized glutathione and dehydroascorbate were increased. The results presented on changes
in enzymatic and nonenzymatic antioxidants suggest that preliminary H2O2 application to pea plants treated with PQ, alleviates the toxic effects of the herbicide. 相似文献
12.
13.
Ultraviolet-B (UV-B) radiation has a negative impact on plant cells, and results in the generation of reactive oxygen species (ROS). In order to increase our understanding of the effects of UV-B on antioxidant processes, we investigated the response of an ascorbate-deficient Arabidopsis thaliana mutant vtc1 to short-term increased UV-B exposure. After UV-B supplementation, vtc1 mutants exhibited oxidative damage. Evidence for damage included an increase in H(2)O(2) content and the production of thiobarbituric acid reactive substances (TBARS); a decrease in chlorophyll content and chlorophyll fluorescence parameters were also reported. The vtc1 mutants had higher total glutathione than the wild type (WT) during the first day of UV-B treatment. We found reduced ratio of glutathione/total glutathione and increased ratio of dehydroascorbate/total ascorbate in the vtc1 mutants, compared to the WT plants. In addition, the enzymes responsible for ROS scavenging, including superoxide dismutase, catalase, and ascorbate peroxidase, had insufficient activity in the vtc1 mutants, compared to the WT plants. The same reduced activity in the vtc1 mutants was reported for the enzymes responsible for the regeneration of ascorbate and glutathione (including monodehydroascorbate reductase, dehydroascorbate reductase, and glutathione reductase). These results suggest that the ascorbate-deficient mutant vtc1 is more sensitive to supplementary UV-B treatment than WT plants and ascorbate can be considered an important antioxidant for UV-B radiation. 相似文献
14.
The comparative alterations of short term NaCl stress and recovery on growth, water relations, ionic composition, lipid peroxidation
and antioxidants in roots of two rice cultivars differing in salt tolerance were studied. Exposed for 24 h to increasing (50,
100 and 150 mmol l−1) concentrations of NaCl, roots of 12D Oryza sativa L. cv. Lunishree and cv. Begunbitchi decreased in fresh weight, dry weight and relative water content. Increased Na+ and decreased K+ ion were determined at increasing NaCl concentrations. Both peroxide content and lipid peroxidation measured in terms of
MDA level increased and the ratio was higher in Begunbitchi compared to Lunishree. Recovered roots showed lower peroxide and MDA content. Ascorbate and glutathione contents increased in the stressed and
recovered roots of Lunishree, but decreased in Begunbitchi with increasing NaCl concentrations. Although SOD, CAT and GR activities decreased in the stressed roots, CAT activity also
increased in recovered roots of both the cultivars. The POX activity increased in stressed and recovered roots of both Lunishree and Begunbitchi. Higher free radicals scavenging capacity and more efficient protection mechanism of Lunishree against salt stress, as revealed by the lower level of lipid peroxidation and improved plant water status as well as activities
of some of the antioxidants, suggest that significant cultivar differences in response to salt stress in rice are closely
related to differences in the activities of antioxidants and ion content. Another possible conclusion is that improved tolerance
to salt stress may be accomplished by increased capacity of antioxidative system. 相似文献
15.
Drought is an important environmental factor that can affect rhizobial competition and N2 fixation. Three alfalfa (Medicago sativa L. and M. falcata L.) accessions were grown in pots containing soil from an irrigated (Soil 1) and a dryland (Soil 2) alfalfa field in northern
Utah, USA. Mutants of three strains of Rhizobium meliloti Dang. from Pakistan (UL 136, UL 210, and UL 222) and a commercial rhizobial strain 102F51a were developed with various levels
of resistance to streptomycin. Seeds inoculated with these individual streptomycin-resistant mutants were sown in the two
soils containing naturalized rhizobial populations. Soils in the pots were maintained at −0.03, −0.5, and −1.0 MPa. After
10 weeks, plants were harvested and nodule isolates were cultured on agar medium with and without streptomycin to determine
nodule occupancy (proportion of the nodules occupied by introduced rhizobial strains). Number of nodules, nodule occupancy,
total plant dry weight, and shoot N were higher for Soil 1 than Soil 2. Number of nodules, plant dry weight, and shoot N decreased
as drought increased from −0.03 to −1.0 MPa in the three alfalfa accessions. Rhizobial strains UL 136 and UL 222 were competitive
with naturalized alfalfa rhizobia and were effective at symbiotic N2 fixation under drought. These results suggest that nodulation, growth, and N2 fixation in alfalfa can be improved by inoculation with competitive and drought-tolerant rhizobia and may be one economically
feasible way to increase alfalfa production in water-limited environments.
Joint contribution from USDA-ARS and the Utah Agric. Exp. Sta., Utah State Univ., Logan, UT 84322-4810, USA. Journal Paper
No. 4931.
Joint contribution from USDA-ARS and the Utah Agric. Exp. Sta., Utah State Univ., Logan, UT 84322-4810, USA. Journal Paper
No. 4931. 相似文献
16.
T. Zhu H. L. Mogensen S. E. Smith 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1991,81(1):21-26
Summary Studies utilizing restriction analysis of plastid DNA, as well as those employing chlorophyll-deficient mutants, have shown a high frequency of paternal plastid transmission in alfalfa. Recent research has also shown that plastid inheritance patterns among alfalfa genotypes and are under genetic control. In a previous study we were unable to detect any correlations between qualitative, three-dimensional ultrastructure of generative cells and male plastid transmission strength in certain genotypes. In the present study we used serial ultrathin sectioning, computerized reconstruction and quantitation, and stereology to further analyze generative cells within mature pollen. Measurements included volumes and surface areas of cells, nuclei, and organelles, as well as organelle number and distribution. Three genotypes were investigated, one that is a strong transmitter of male plastids (genotype 301), one that is a weaker transmitter of male plastids (genotype 7W), and a third that is an even weaker male plastid transmitter (genotype MS-5). Our results show that genotype MS-5 has significantly fewer plastids/generative cell than either of the other genotypes, which may account for it being a relatively poor transmitter of male plastids. However, plastid number does not explain known differences in male plastid inheritance between genotypes 301 and 7W, since plastid number does not differ significantly between these two genotypes. Regarding the other features of generative cells measured in this study, no consistent correlations were found that might account for differences in male plastid inheritance patterns between genotypes. Plastid distribution is equal in each end of the spindle-shaped generative cell in all genotypes studied. Similar relative results were found with regard to mitochondria within generative cells; however, comparative genetic data are not available on mitochondrial transmission patterns in alfalfa genotypes. 相似文献
17.
Otvös K Pasternak TP Miskolczi P Domoki M Dorjgotov D Szucs A Bottka S Dudits D Fehér A 《The Plant journal : for cell and molecular biology》2005,43(6):849-860
It is now well established that nitric oxide (NO) serves as a signaling molecule in plant cells. In this paper experimental data are presented which indicate that NO can stimulate the activation of cell division and embryogenic cell formation in leaf protoplast-derived cells of alfalfa in the presence of auxin. It was found that various NO-releasing compounds promoted auxin-dependent division (as shown by incorporation of bromodeoxyuridine) of leaf protoplast-derived alfalfa cells. In contrast, application of NO scavenger or NO synthesis inhibitor inhibited the same process. Both the promotion and the inhibition of cell cycle activation correlated with the amount and activity of the cognate alfalfa p34cdc2 protein Medsa;CDKA;1,2. The effect of l-NG-monomethyl-L-arginine (L-NMMA) was transient, and protoplast-derived cells spending more than 3 days in culture become insensitive to the inhibitor as far as cell cycle progression was concerned. L-NMMA had no effect on the cell cycle parameters of cycling suspension-cultured cells, but had a moderate transient inhibitory effect on cells re-entering the cell cycle following phosphate starvation. Cycling cultured cells, however, could respond to NO, as indicated by the sodium nitroprusside (SNP)- and 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (PTIO)-dependent accumulation of the ferritin protein. Based on these observations, it is hypothesized that L-NMMA-sensitive generation of NO is involved in the activation, but not the progression of the plant cell division cycle. In addition, SNP promoted and L-NMMA delayed the exogenous auxin [2,4-dichlorophenoxyacetic acid (2,4-D)] concentration-dependent formation of embryogenic cell clusters expressing the MsSERK1 gene; this further supports a link between auxin- and NO-dependent signaling pathways in plant cells. 相似文献
18.
Shi-Weng Li Lingui Xue Shijian Xu Huyuan Feng Lizhe An 《Environmental and Experimental Botany》2009,66(3):442-450
The changes in antioxidant enzyme activity during the induction of adventitious roots in mung bean seedlings treated with Indole-3-butyric acid (IBA), hydrogen peroxide (H2O2), ascorbic acid (ASA) and diphenylene iodonium (DPI) were investigated. As compared with the controls, treatments of seedlings with 10 μM IBA significantly decreased POD activity by 55% and 49.6% at 3 h and 12 h of incubation, respectively, and significantly increased by 49.8% at 36 h of incubation; treatments of seedlings with 10 mM H2O2 significantly decreased POD activity by 42%, 60%, 39% and 38% at 3 h, 12 h, 24 h and 48 h of incubation, respectively, the changes in POD activity were coincident with those in IBA-treated seedlings during the 0–12 h incubation period; treatments of seedlings with 2 mM ASA significantly decreased APX activities by 27% only at 3 h of incubation, the varying trend of POD activity was similar to incubation with water; 10 μM DPI treatments significantly decreased POD activity by 42%, 40%, 54% and 28% at 3 h, 6 h, 12 h and 48 h of treatment, respectively. CAT activities remained at relatively stable levels and no major changes occurred from 0 h to 48 h during the incubation phase of adventitious rooting. The results may imply that CAT, an H2O2-metabolizing enzyme, is inactivated by H2O2 during the formation of adventitious roots. As compared with the controls, IBA treatments significantly decreased APX activities by 48%, 53% and 66% at 3 h, 9 h and 12 h of treatment, respectively; H2O2 treatments significantly decreased APX activities by 59%, 51% and 57% at 3 h, 12 h and 36 h of incubation, respectively; ASA treatments significantly decreased APX activities by 37% only at 3 h of incubation; DPI treatments significantly decreased APX activities by 54%, 53% and 63% at 3 h, 6 h and 12 h of incubation, respectively, and significantly increased APX activity by 106% at 24 h. These results indicated that the influence of IBA, H2O2, ASA and DPI on the changes in APX activity were the same as on the changes in POD activity. Furthermore, similar trends in the changes of APX activity and POD activity were observed during the induction and initiation rooting phase. This finding implies that APX and POD serve the same functions, possibly related to the level of H2O2, during the formation of adventitious roots. The early decrease of POD and APX activities in the initiation phase of IBA- and H2O2-treated seedlings may be one mechanism underlying the IBA- and H2O2-mediated facilitation of adventitious rooting. 相似文献
19.