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1.
Summary The growth retardant ancymidol inhibited gibberellin biosynthesis and enhanced hyperhydric malformation of Narcissus leaf sections cultured in liquid medium. Superoxide dismutase activities were examined by spectrophotometry and native polyacrylamide
gel analysis, and gibberellin and hydrogen peroxide levels were determined spectrophotometrically in either hyperhydric or
non-hyperhydric leaf sections. In ancymidol-treated hyperhydric leaf sections, superoxide dismutase activity and hydrogen
peroxide levels were higher during the initial culture period, when hyperhydric malformation occurred, than in control untreated
leaf sections. At a later stage, when the meristematic centers started to form on ancymidol-enhanced hyperhydric leaf sections,
superoxide dismutase activity, hydrogen peroxide, and gibberellin levels were significantly lower in hyperhydric leaf sections
than in non-treated leaf sections. The changes in superoxide dismutase activities, hydrogen peroxide, and gibberellin levels
appeared to be related to hyperhydric malformation and meristematic center initiation. 相似文献
2.
Summary The use of scaled-up liquid cultures could be an efficient system for mass propagation of Narcissus, as it can greatly reduce the costs involved with manual handling. Induction of hyperhydric meristematic leaf section clusters
and proliferation were carried out in an ancymidol (ANC)-containing liquid medium in flasks and disposable presterilized plastic
bioreactors. Non-hyperhydric bulblets started to develop from hyperhydric meristematic leaf section clusters after subculture
on a 0.8% agar strength medium, and young bulbs formed after 10 mo. in vivo acclimatization with a 98% survival rate. The present study reveals that in Narcissus leaf sections cultured in liquid medium, morphogenetic changes in leaf sections were associated with metabolic changes. The
changes in carbohydrate, protein, and water potential of the liquid media and leaf sections were found to be closely related
to meristematic center initiation on Narcissus hyperhydric leaf sections. Starch, sucrose, and glucose were significantly higher in the hyperhydric leaf sections cultured
in ANC medium. The water potential was signifieantly higher in ANC-treated leaf sections and significantly lower in the medium
containing ANC, at the stage shortly before or after hyperhydricity and meristematic centers hegan forming on the leaf sections.
A 30kDa protein was found to be present in the hyperhydric leaf sections. Based on the present study, a largescale micropropagation
protocol of Narcissus in agar and liquid cultures is proposed. 相似文献
3.
Enhanced bud regeneration in aspen (Populus tremula L.) roots cultured in liquid media 总被引:3,自引:0,他引:3
The regeneration potential of excised aspen (Populus tremula L.) roots cultivated in liquid medium, as affected by plant growth regulators and by the position of the isolated root explant
on the main root, was investigated. The effect of various levels of benzyladenine (BA) and thidiazuron (TDZ) on bud regeneration
in root explants was studied. TDZ in the medium had a marked effect on bud development as compared with BA, inducing a tenfold
increase in the number of buds regenerated from various root explants. TDZ enhanced both root and root-borne shoot biomass
production but reduced further shoot development and elongation. The position of the isolated root sections on the main root
affected regeneration, the proximal sections further away from the root tip producing the highest number of buds per explant
in both BA and TDZ treatments. Buds regenerated in close proximity to the site of lateral roots in BA-treated roots, while
in TDZ-treated root sections, the buds formed all over the root regardless of the presence of lateral roots. The buds developed
from inner cortical and sub-epidermal cell layers, disrupting the epidermis and the inner layers. Root biomass production
and growth was greatly enhanced in well-aerated bioreactor culture in the presence of 4.5×10–2 μM TDZ. A high number of the root-borne shoots could be rooted and converted to plantlets. However, while shoots regenerated
in a medium with BA rooted well in a growth regulator-free medium, shoots formed in a medium with TDZ required auxin for rooting.
Roots cultured in the presence of ancymidol, a gibberellin biosynthesis inhibitor, regenerated non-hyperhydric bud clusters
and hyperhydric shoots. These were separated mechanically, subcultured to growth and rooting medium and transplanted ex vitro
resulting in phenotypically true-to-type plantlets. The potential of liquid cultures for aspen shoot biomass production from
roots is discussed.
Received: 24 January 2000 / Revision received: 6 March 2000 / Accepted: 7 March 2000 相似文献
4.
Hyperhydricity is a physiological disorder frequently affecting shoots propagated in vitro. Since it negatively affects shoot multiplication vigor, and impedes the successful transfer of micropropagated plants to
in vivo conditions, hyperhydricity is a major problem in plant tissue culture. In commercial plant micropropagation, there are reports
of up to 60% of cultured shoots or plantlets which demonstrate hyperhydricity, which reflects the pervasiveness of this problem.
The phenomenon has been correlated to water availability, microelements, and/or hormonal imbalance in the tissue culture.
In this study, the ultrastructure and the characteristics of reactive oxygen species between hyperhydric and normal shoots
of garlic were studied. We observed that in some cells of hyperhydric tissues, the intranuclear inclusion was separated, the
mitochondrion was swollen and its intracristae had splits, the organelles were compressed against the cell wall, and the chloroplasts
and intergranal thylakoids were also compressed. Additionally, the content of chlorophyll and soluble protein in hyperhydric
shoots decreased significantly. For instance, chlorophyll a decreased 43.61%, chlorophyll b decreased 49.29%, chlorophyll
a+b decreased 48.10%, and soluble protein dropped 47.36%. In contrast, the O2 generation rate and H2O2 level increased 45.36% and 63.98%, respectively, obviously higher than the normal shoots. Lipoxygenase activity and malondialdehyde
content in the hyperhydric shoots increased significantly, while the electrolyte leakage rose, indicating a serious membrane
lipid peroxidatic reaction. Superoxide dismutase, peroxidase, catalase, glutathione peroxidase, and ascorbate peroxidase activities
in hyperhydric tissue were all significantly higher than in normal leaf tissue. The antioxidant metabolism demostrated a close
connection between hyperhydricity and reactivated oxygen species. 相似文献
5.
Vitrification of shoots of Prunus avium L. L. was induced and expressed in a four week in vitro multiplication cycle simply by replacing agar by gelrite. The first vitrification symptoms were visible from the 7th day on. Enzymatic antioxidants were compared weekly in crude extract of normal (on agar) and vitrifying (on gelrite) shoots. The activity of superoxide dismutase was higher in vitrifying shoots. The other enzymes (gaîacol-peroxidase, catalase, ascorbate peroxidase, mono- and dehydro-ascorbate reductases, glutathione reductase) had lower activities. Increased superoxide dismutase activity might mean hydrogen peroxide accumulation and decreased activities of the other enzymes, deficiency in its detoxification. The question therefore is raised whether the hyperhydric morphological abnormalities result from the accumulation of toxic oxygen forms. Vitrification is often considered as a morphological response to several stresses. Contrary to most plants which adapt themselves to stresses by increasing all the above defence enzymes, in vitro shoots under vitrifying conditions appear unable to react in a similar manner.Abbreviations Apx
ascorbate peroxidase
- Gpx
gaîacol peroxidase
- CAT
catalase
- H2O2
hydrogen peroxide
- SOD
superoxide dismutase
- MDHAR
monodehydroascorbate reductase
- DHAR
dehydroascorbate reductase
- GR
glutathione reductase
- MS
Murashige and Skoog (1962)
- IBA
indolebutyric acid
- BAP
benzyladenine
- GA3
gibberellic acid 相似文献
6.
《Environmental and Experimental Botany》2007,59(1-3):93-99
A large number of micropropagated Euphorbia millii shoots from temporary immersion bioreactor showed thick broad leaves that were translucent, wrinkled and/or curled and brittle, symptoms of hyperhydricity. The environment inside bioreactor normally used in plant micropropagation is characterised by high relative humidity, poor gaseous exchange between the internal atmosphere of the bioreactor and its surrounding environment, and the accumulation of ethylene, conditions that may induce physiological disorders. A comparison of hyperhydric shoots (HS) with normal plants shows marked increase in malondialdehyde (MDA) content in HS plants. MDA, a decomposition product of polyunsaturated fatty acids hydroperoxides, has been utilized very often as a suitable biomarker for lipid peroxidation, which is an effect of oxidative damage. This hypothesis is also confirmed by the higher lipoxygenase (LOX) activity in HS plants. The potential role of antioxidant enzymes in protecting hyperhydric shoots from oxidative injury was examined by analyzing enzyme activities and isozyme profiles of hyperhydric and non-hyperhydric leaves of E. millii. Superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) activity were significantly higher in hyperhydric tissue as compared to non-hyperhydric normal leaf tissue. After native polyacrylamide gel electrophoresis (PAGE) analysis, seven SOD isoenzymes were detected and the increase in SOD activity observed in hyperhydric tissue seemed to be mainly due to Mn-SOD and Cu/Zn-SOD. The activity of ascorbate peroxidase (APX), glutathione reductase (GR), monodehydroascorbate reductase (MDHAR) and dehydroascorbate reductase (DHAR) was proportionally increased in HS tissue compared to normal leaves indicating a crucial role in eliminating toxic H2O2 from plant cells. The depletion of GSH and total glutathione in spite of higher GR activities observed in HS tissue indicates that mechanism of antioxidant defense was by enhanced oxidation of GSH to GSSG by DHAR yielding ascorbate (AA). The antioxidant metabolism has been shown to be important in determining the ability of plants to survive in hyperhydric stress and the up regulation of these enzymes would help to reduce the build up of ROS. 相似文献
7.
Bilal Haider Abbasi Murad Khan Bin Guo Saleem Ahmed Bokhari Mir Ajab Khan 《Plant Cell, Tissue and Organ Culture》2011,105(3):337-344
The regeneration potential and antioxidative enzyme activities of economically important Brassica rapa var. turnip were evaluated. Calli were induced from leaf explants of seed-derived plantlets on Murashige and Skoog (MS) medium incorporated
with different concentrations of various plant growth regulators (PGRs). The highest leaf explant response (83%) was recorded
for 2.0 mg l−1 benzyladenine (BA) and 1.0 mg l−1 α-naphthaleneacetic acid (NAA). Subsequent subculturing of callus after 3 weeks of culture, on medium with similar compositions
of PGRs, induced shoot organogenesis. The highest shoot induction response (83%) was recorded for 5.0 mg l−1 BA after 5 weeks of transfer. However, 7.8 shoots/explant were recorded for 2.0 mg l−1 BA. The transferring of shoots to elongation medium resulted in 5.1-cm-long shoots on 10 mg l−1 of gibberellic acid (GA3). Rooted plantlets were obtained on MS medium containing different concentrations of indole butyric acid (IBA). The determination
of activities of antioxidative enzymes (superoxide dismutase [SOD], ascorbate peroxidase [APX], catalase [CAT], glutathione
peroxidase [GPX], and peroxidase [POD]) revealed involvement of these enzymes in callus formation and differentiation. All
of the activities were interlinked with each other and played significant roles in the scavenging of toxic free radicals.
This study will help in the advancement of a regeneration protocol for B. rapa var. turnip and the understanding of the functions of antioxidative enzymes in plant differentiation. 相似文献
8.
In vitro shoot regeneration of gladiolus in three different culture systems, viz., semi-solid agar (AS), membrane raft (MR),
and duroplast foam liquid (DF) cultures was evaluated following the kinetics of shoot multiplication and hyperhydricity at
optimized growth regulator combinations. Compared to the AS system, matrix-supported liquid cultures enhanced shoot multiplication.
The peak of shoot multiplication rate was attained at 18 days of incubation in the MR and DF systems, whereas the maximum
rate in the AS system was attained at 21 days. An early decline in acceleration trend was observed in liquid cultures than
the AS culture. The hyperhydric status of the regenerated shoots in the different culture systems was assessed in terms of
stomatal attributes and antioxidative status. Stomatal behavior appeared to be normal in the AS and MR systems. However, structural
anomaly of stomata such as large, round shaped guard cells with damage in bordering regions of stomatal pores was pronounced
in the DF system along with a relatively higher K+ ion concentration than in the AS and MR systems. Antioxidative status of regenerated shoots was comparable in the AS and
MR systems, while a higher incidence of oxidative damages of lipid membrane as evidenced from malondialdehyde and ascorbate
content was observed in the DF system. Higher oxidative stress in the DF system was also apparent by elevated activities of
superoxide dismutase, ascorbate peroxidase, and catalase. Among the three culture systems, liquid culture with MR resulted
in maximum shoot multiplication with little or no symptoms of hyperhydricity. Shoots in the DF system were more prone to hyperhydricity
than those in the AS and MR systems. The use of matrix support such as membrane raft as an interface between liquid medium
and propagating tissue could be an effective means for rapid and efficient mass propagation with little or no symptoms of
hyperhydricity. 相似文献
9.
Hyperhydricity is a physiological abnormality that frequently affects shoots that are vegetatively propagated in vitro. In this study, sugar beet (Beta vulgaris L. cv. Felicita) shoot tip explants were cultured on Murashige and Skoog medium supplemented with different concentrations of polyethylene glycol (PEG) 6000. We observed that higher concentrations of PEG 6000 and longer exposure (up to 4 wk) resulted in increasing levels of hyperhydration as well as browning and/or blackening of tissues in culture. A comparison of hyperhydric shoots with controls on the 28th day showed a marked increase in the content of water, phenolics, and malondialdehyde (MDA), which was positively correlated with an increase in the accumulation of PEG 6000. Selected antioxidant enzyme activities, including superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), guaiacol peroxidase (POX), and polyphenol oxidase (PPO) also increased in hyperhydric shoots, especially at lower concentrations of PEG 6000. Regression analysis indicated that strong linear relationships exist between SOD–APX (R 2?=?0.932), SOD–CAT (R 2?=?0.753), SOD–total phenolic content (R 2?=?0.966), APX–PPO (R 2?=?0.842), APX–total phenolic content (R 2?=?0.904), POX–CAT (R 2?=?0.751), and CAT–total phenolic content (R 2?=?0.806). Despite the correlation between different antioxidant enzymes and between the antioxidant enzymes and antioxidant compounds, was not able to prevent ROS damage in hyperhydric shoots. The negative correlation between SOD–MDA, POX–MDA, CAT–MDA, and MDA–total phenolics also indicated an increase in antioxidant enzyme activities, yet the increase in these antioxidant compound contents did not prevent lipid peroxidation of in vitro propagated beet shoots. 相似文献
10.
Response of the cherry rootstock to water stress induced <Emphasis Type="Italic">in vitro</Emphasis> 总被引:1,自引:1,他引:0
N. Sivritepe U. Erturk C. Yerlikaya I. Turkan M. Bor F. Ozdemir 《Biologia Plantarum》2008,52(3):573-576
The in vitro response of sweet cherry (Prunus cerasus × P. canescens) rootstock Gisela 5 to increasing water deficit in the culture medium was studied. Water stress induced by the incorporation
of 1, 2 and 4 % polyethylene glycol (PEG-8000) into the Murashige and Skoog medium was applied for 6 weeks. PEG-induced water
stress reduced shoot dry mass, length, water content and relative chlorophyll content. Water stress also induced leaf necrosis
without causing loss of viability in the explants. The increase in malondialdehyde content indicated oxidative stress. The
activities of antioxidant enzymes, such as superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), peroxidase
(POX) and glutathione reductase (GR) were also significantly elevated. The concentrations of K, Ca, Fe and Mn of shoots were
decreased. 相似文献
11.
Biljana Balen Mirta Tkalec Dubravko Pavoković Branka Pevalek-Kozlina Marijana Krsnik-Rasol 《Journal of Plant Growth Regulation》2009,28(1):36-45
In vitro propagated plants of Mammillaria
gracilis Pfeiff. (Cactaceae) develop calli without any exogenous growth regulators. This habituated tissue spontaneously regenerates morphologically
normal as well as hyperhydric shoots. In this study, a possible involvement of activated oxygen metabolism in habituation
and hyperhydricity in in vitro propagated plants of Mammillaria
gracilis Pfeiff. (Cactaceae) was investigated. Significantly higher malondialdehyde (MDA) and carbonyl contents as well as hydrogen peroxide (H2O2) production were observed in habituated callus (HC), hyperhydric regenerated shoots (HS), and tumors (TT) in comparison to
normal regenerated shoots (NS). Lipoxygenase (LOX) activity showed a similar trend, with a clear increase in activity in HC
and HS. The activities of antioxidative enzymes, namely, peroxidase (POX), ascorbate peroxidase (APX), and catalase (CAT),
were also higher in HC, HS, and TT, whereas an increase in superoxide dismutase (SOD) activity was observed in HC and HS.
The majority of antioxidative isoenzymes were common to all cactus tissues, although a few tissue-specific bands were noticed.
Significant decreases in phenylalanine ammonia lyase (PAL) activity, total phenolic content, and lignification were found
in HS, HC, and TT in comparison to NS. Our results showed the appearance of a prominent oxidative stress in HC, HS, and TT
as well as a strong induction of the antioxidant system indicating that activated oxygen metabolism could be involved in habituation
and hyperhydricity and linked to the loss of tissue organization in M. gracilis.
B. Balen and M. Tkalec contributed equally to this work. 相似文献
12.
The effects of exogenous abscisic acid (ABA) on lead tolerance in rice (Oryza sativa L.) seedlings were investigated. Pre-treatment with 0.1 g m3 ABA for 2 d restricted amount of Pb translocated from roots to shoots, decreased malondialdehyde and H2O2 contents in leaves, and alleviated Pb-induced decrease in plant growth and leaf chlorophyll content. Further, ABA pre-treatment
adjusted leaf antioxidative enzyme activities (increased ascorbate peroxidase and catalase activities while decreased superoxide
dismutase activity) and so alleviated oxidative stress. 相似文献
13.
V. Paranidharan A. Palaniswami P. Vidhyasekaran R. Velazhahan 《Acta Physiologiae Plantarum》2003,25(1):91-96
Changes in the activities of peroxidase, ascorbate peroxidase, catalase and superoxide dismutase in rice in response to infection
by Rhizoctonia solani were studied. A significant increase in peroxidase activity was observed in R. solani-inoculated rice leaf sheaths 1 day after inoculation and the maximum enzyme activity was recorded 3 days after inoculation
at which period a 3-fold increase in peroxidase activity was observed compared to the untreated control. Three peroxidase
isozymes viz., PO-4, PO-5 and PO-6 were induced in rice upon infection by R. solani. Ascorbate peroxidase and catalase activities significantly increased 1–2 days after inoculation and the maximum enzyme activities
were recorded 5 days after inoculation. Superoxide dismutase activity increased significantly 2 days after inoculation and
increased progressively, reaching four times the control value at 7 days after inoculation. 相似文献
14.
Summary Single node stem segments fromin vitro potato shoots cultured in liquid medium in the presence of ancymidol (23.4 μM) developed into bud clusters in either shaken flasks or bioreactor cultures. Buds on the clusters developed tubers after
subculture to a tuber induction medium with 23.2 μM kinetin, 19.5 μM ancymidol, and 6-8% sucrose. The number of tubers per cluster and their size were higher in agar induction medium on top
of which a second layer of liquid medium was added, than in liquid shake or bioreactor cultures. The highest increase in tuber
size (i.e., 720 mg fresh weight after 7 weeks), was obtained in agar cultures flushed twice with liquid tuber induction medium.
The potential of bioreactor cultures for potato bud proliferation and enhanced tuber development in double layer agar-liquid
cultures is discussed. 相似文献
15.
Changes in apoplastic antioxidants induced by powdery mildew attack in oat genotypes with race non-specific resistance 总被引:1,自引:0,他引:1
Three oat (Avena sativa L.) lines which show differential responses to attack by the biotrophic fungal pathogen Blumeria graminis DC f. sp. avenae Marchal, which causes powdery mildew, were studied: Maldwyn shows the strongest resistance in adult plants; Selma shows greater
susceptibility; while a Selma × Maldwyn hybrid, OM1387, has a similar degree of resistance to Maldwyn. Host responses to pathogen
attack were complete 48 h after inoculation but largely accomplished within the first 24 h, the point when material was taken
for enzyme and metabolic assays. In Maldwyn and OM1387 about 80% of attacked cells showed localized autofluorescent host-cell
responses but this fell to less than 20% in Selma. A cytoplasmic marker enzyme, glucose 6-phosphate dehydrogenase, was used
to determine contamination of the apoplastic extracts by cellular components. After correction for cytoplasmic contamination,
up to 4% of the total foliar activities of superoxide dismutase, catalase, ascorbate peroxidase, glutathione reductase, dehydroascorbate
reductase and monodehydroascorbate reductase activities were detected in the apoplast. The apoplast contained about 2% of
the total foliar glutathione pool and dehydroascorbate, but not ascorbate, at values amounting to 10% of the total foliar
ascorbate plus dehydroascorbate pool. Twenty-four hours after inoculation the foliar or apoplastic ascorbate pools were similar
in inoculated and control leaves. Foliar catalase activity increased in both susceptible and resistant responses. Resistance
correlated with increased total foliar glutathione, an increase in the ratio of reduced to oxidized glutathione and with decreased
total activities of foliar ascorbate peroxidase, glutathione reductase, dehydroascorbate reductase and monodehydroascorbate
reductase.
Received: 17 April 1998 / Accepted: 28 August 1998 相似文献
16.
B. P. Shaw 《Biologia Plantarum》1995,37(4):587-596
Phaseolus aureus Roxb. was exposed to HgCl2 and Cd(NO3)2 either at the germination stage in concentration 0.5, 5 and 25 μM for 48 and 96 h, or at the seedling stage (5th day of germination) in concentration 0.5, 5 and 20 μM for 6, 24 and 48 h. The germination and the growth of roots (germination
stage treatment) were less in Hg than in Cd treatment. The seedlings (seedling stage treatment) were, however, more susceptible
to Cd than Hg. Both root and leaf tissues of the plant treated at the germination stage showed enhanced lipid peroxidation
and activities of the antioxidative enzymes (catalase, guaiacol peroxidase and ascorbate peroxidase), except the catalase
in leaf in 25 μM Cd treatment. At seedling stage the content of malondialdehyde increased significantly only in the leaf tissue,
during 6 h exposure. The activities of all the enzymes exhibited an increasing trend in both the tissue of the seedlings,
particularly the leaf, at least after 24 and 48 h, except the catalase whose activity declined in response to Cd. Active involvement
of the guaiacol and ascorbate peroxidases, rather than catalase, in scavenging cellular H2O2 was indicated. It was concluded that the two metals had little primary damaging effect on membranes. 相似文献
17.
Arti Gautam Akhilesh Kumar Pandey Rama Shanker Dubey 《Physiology and Molecular Biology of Plants》2020,26(1):63-81
In the present study the potentials of aqueous extracts of the two plants, neem (Azadirachta indica) and Tulsi (Ocimum sanctum) were examined in alleviating arsenic toxicity in rice (Oryza sativa L.) plants grown in hydroponics. Seedlings of rice grown for 8 days in nutrient solution containing 50 μM sodium arsenite showed decline in growth, reduced biomass, altered membrane permeability and increased production of superoxide anion (O2·−), H2O2 and hydroxyl radicals (·OH). Increased lipid peroxidation marked by elevated TBARS (thiobarbituric acid reactive substances) level, increased protein carbonylation, alterated levels of ascorbate, glutathione and increased activities of enzymes SOD (superoxide dismutase), CAT (catalase), APX (ascorbate peroxidase) and GPX (glutathione peroxidase) were noted in the seedlings on As treatment. Exogenously added leaf aqueous extracts of Azadirachta indica (0.75 mg mL−1, w/v) and Ocimum sanctum (0.87 mg mL−1, w/v) in the growth medium considerably alleviated As toxicity effects in the seedlings, marked by reduced As uptake, restoration of membrane integrity, reduced production of ROS, lowering oxidative damage and restoring the levels of ascorbate, glutathione and activity levels of antioxidative enzymes. Arsenic uptake in the seedlings declined by 72.5% in roots and 72.8% in shoots, when A. indica extract was present in the As treatment medium whereas with O. sanctum extract, the uptake declined by 67.2% in roots and 70.01% in shoots. Results suggest that both A. indica and O. sanctum aqueous extracts have potentials to alleviate arsenic toxicity in rice plants and that A. indica can serve as better As toxicity alleviator compared to O. sanctum. 相似文献
18.
D. Talukdar 《Biologia Plantarum》2012,56(4):675-682
An ascorbate-deficient semi-dwarf mutant asfL-1 was detected in 250 Gy γ-ray treated grass pea (Lathyrus sativus L.) cv. BioR-231. The mutant contained only 42 % of leaf and 20 % of root ascorbate content of mother control (MC). I investigated the possible causes of ascorbate deficiency and its effect on growth and antioxidant defense in control and 150 mM NaCl-treated seedling after 60 d growth period. Ascorbate deficiency was due to significant reduction in activities of monodehydroascorbate reductase and dehydroascorbate reductase as well as increase in ascorbate oxidase, leading to considerable decrease in redox state. Despite low ascorbate pool and decrease in ascorbate peroxidase activity, shoot and root biomass production in asfL-1 mutant were similar to MC plants, even at NaCl treatment. High accumulation of glutathione (GSH) coupled with high activities of GSH reductase, catalase, GSH peroxidase and peroxidase in both tissues of the mutant permitted efficient recycling of GSH and scavenging of H2O2 through well integrated catalase/peroxidase system, despite high superoxide dismutase activity under NaCl treatment. The collapse of this system led to inhibition of growth in NaCl-treated mother plants. Together, the results suggested that asfL-1 plants undertook a major reshuffle in its antioxidant defense machinery, which effectively counterbalanced the negative impact of ascorbate deficiency and remained unperturbed by NaCl treatment to maintain normal growth and biomass production. 相似文献
19.
An efficient in vitro regeneration protocol was developed for medicinally important aromatic plant Anethum graveolens. Nodal segments were cultured onto Murashige and Skoog (MS) basal medium supplemented with different auxins and cytokinins
singly as well as in combinations. The optimum callus induction (93.33 %) was obtained on medium fortified with 2.2 μM N6-benzyladenine (BA) and 0.21 μM α-naphthaleneacetic acid. The best shoot regeneration (85.7 %) with 12.86 shoots per explant
was achieved in two weeks when callus was subcultured on MS medium amended with 2.2 μM BA and 1.85 μM kinetin. The average
length of regenerated shoots varied from 3.15 to 4.8 cm. The rooting of regenerated shoots was nearly 100 % on ? MS augmented
with 4.9 μM indolebutyric acid with a maximum root length of 5.1 cm. Plantlets were successfully acclimatized with 60 % survival
rate. During organogenesis, catalase and ascorbate peroxidase activity increased while superoxid dismutase activity decreased.
Clonal fidelity of in vitro raised plants has been checked by random amplified polymorphic DNA using 10 selected decamer primers. It has been found that
regenerated plants are true to type plants. 相似文献
20.
Changes in the Activity of Antioxidant Enzymes in Wheat Leaves and Roots as a Function of Nitrogen Source and Supply 总被引:3,自引:0,他引:3
Polesskaya O. G. Kashirina E. I. Alekhina N. D. 《Russian Journal of Plant Physiology》2004,51(5):615-620
The activity of enzymes participating in the systems of antioxidant protection was assayed in the second leaf and roots of 21-day-old wheat seedlings (Triticum aestivum L.) grown in a medium with nitrate (NO–
3 treatment), ammonium (NH+
4 treatment), or without nitrogen added (N-deficiency treatment). The activities of superoxide dismutase (SOD), peroxidase, ascorbate peroxidase, glutathione reductase, and catalase in the leaves and roots of the NH+
4 plants was significantly higher than in the plants grown in the nitrate medium. The activity of SOD decreased and ascorbate peroxidase markedly increased in leaves, whereas the activity of ascorbate peroxidase increased in the roots of N-deficient plants, as compared to the plants grown in nitrate and ammonium. Low-temperature incubation (5°, 12 h) differentially affected the antioxidant activity of the studied plants. Whereas leaf enzyme activities did not change in the NH+
4 plants, the activities of SOD, peroxidase, ascorbate peroxidase, and catalase markedly increased in the NO–
3 plants. In leaves of the N-deficient plant, the activity of SOD decreased; however, the activity of other enzymes increased. In response to temperature decrease, catalase activity increased in the roots of NO–
3 and NH+
4-plants, whereas in the N-deficient plants, the activity of peroxidase increased. Thus, in wheat, both nitrogen form and nitrogen deficiency changed the time-course of antioxidant enzyme activities in response to low temperature. 相似文献