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1.
An effort has been made to assess the role of reactive oxygen species in germination and subsequent growth of Amaranthus lividus under elevated temperature. Transfer of A. lividus seeds from 25 to 45 °C for 4, 8 and 12 h, during early imbibitional period reduced percentage of germination, relative germination performance, relative growth index and seedling length. Heat shock during early germination decreased also the activities of free radical scavenging enzymes like catalase, peroxidase and superoxide dismutase, increased the accumulation of superoxide, hydrogen peroxide and induced lipoxygenase mediated membrane lipid peroxidation. Membrane injury index and relative leakage ratio revealed a rise with concomitant reduction in membrane protein thiol content in heat shock raised seedlings. The results indicate that heat shock in A. lividus seeds induced an excessive generation of ROS and led to an oxidative membrane damage, causing early growth impairment. 相似文献
2.
Soumen Bhattacharjee 《Physiology and Molecular Biology of Plants》2013,19(2):199-207
Extremes of temperature (both heat and chilling) during early inbibitional phase of germination caused disruption of redox-homeostasis by increasing accumulation of reactive oxygen species (superoxide and hydrogen peroxide) and significant reduction of antioxidative defense (assessed in terms of total thiol content and activities of superoxide dismutase, catalase, ascorbate peroxidase and glutathione reductase) in germinating tissues of rice (Oryza sativa L., cultivar Ratna). Imbibitional heat and chilling stress also induced oxidative damage to newly assembled membrane system by aggravating membrane lipid peroxidation and protein oxidation [measured in terms of thiobarbituric acid reactive substances (TBARS), free carbonyl content (C = O groups) and membrane protein thiol level (MPTL)]. Treatment with standardized low titer hydrogen peroxide during early imbibitional phase of germination caused significant reversal in oxidative damages to the newly assembled membrane system imposed by heat and chilling stress [evident from the data of TBARS, C = O, MPTL, ROS accumulation, membrane permeability status, membrane injury index and oxidative stress index] in seedlings of experimental rice cultivar. Imbibitional H2O2 pretreatment also caused up-regulation of antioxidative defense (activities of superoxide dismutase, catalase, ascorbate peroxidase, glutathione reductase and total thiol content) in the heat and chilling stress-raised rice seedlings. When the parameters of early growth performances were assessed (in terms of relative growth index, biomass accumulation, relative germination performance, mean daily germination, T50 value), it clearly exhibited significant improvement of early growth performances of the experimental rice cultivar. The result proposes that an ‘inductive pulse’ of H2O2 is required to switch on some stress acclimatory metabolism through which plant restores redox homeostasis and prevents or repairs oxidative damages to newly assembled membrane system caused by unfavorable environmental cues during early germination to the rice cultivar Ratna. The importance of mitigating oxidative damages to membrane lipid and protein necessary for post-germinative growth under extremes of temperature is also suggested. 相似文献
3.
Potted vegetable plants of Amaranthus lividus, Gynandropsis gynandra and Crotalaria brevidens were grown outside under normal tropical conditions and rate of photosynthesis and transpiration were determined simultaneously in attached leaves under a range of leaf temperatures and irradiances. Photosynthetic rates were consistently higher in G. gynandra than in A. lividus and C. brevidens. However, in C. brevidens and G. gynandra the leaf resistances were lower and transpiration rates were higher than those in A. lividus. The results on optimum temperature requirements for maximum rates of CO2 fixation, coupled with data on CO2 compensation points and leaf anatomy provided clear evidence that G. gynandra and A. lividus are C4 species, while C. brevidens is a C3 species. The differential effects of light intensity and temperature on stomata and mesophyll resistances in C3 and C4 species are discussed in relation to rates of photosynthesis and transpiration. 相似文献
4.
The activities and isoenzyme pattern of catalase (CAT), superoxide dismutase (SOD) and peroxidase (POD) have been studied
during germination of Chenopodium murale seeds. CAT and SOD activities were similar in dry seeds and during first 2 d of imbibition. CAT activity increased during
radicle protrusion and early seedling development. The maximum SOD activity was found at final stages of germination and early
seedling development. POD activity was not detected until the 6th day of germination, indicating POD involvement not until early seedling development. Gibberellic acid (GA3, 160 μM) delayed and synchronized C. murale germination. 相似文献
5.
The concentration of kinetin and kinetinriboside plays an essential role in the induction of amaranthin accumulation in cotyledons ofAmaranthus tricolor during germination. The dose/effect ratio shows that kinetin induced 3- to 3.5-fold more amaranthin than kinetinriboside at the same molecular concentration. Various concentrations of exogenous Ca2+ did not influence the effects of kinetin on the betacyanin synthesis. However, when Ca2+ was applied together with kinetinriboside, the amaranthin production was stimulated. Time-course experiments show a lag phase of 16 h starting from the incubation with kinetin and a distinct increase of amaranthin thereafter. If the seedlings were treated simultaneously with kinetin and Ca2+, the increase of amaranthin started after 12 h. At 16 h of incubation in kinetin/Ca2+, the amount of amaranthin increased significantly compared to controls incubated with kinetin alone. If Ca2+ ions (16 h kinetin/Ca2+ incubation) were removed from the medium after 2 h, 4 h, and up to 14 h, the amaranthin content was enhanced compared to controls without Ca2+. The stimulating effect was highest in the presence of Ca2+ for 8 h. These data show that exogenous Ca2+ stimulated the amaranthin synthesis mainly during the first 12 h of incubation. The Ca2+ antagonists EGTA, chlorotetracycline, and CoCl2 reduced the amaranthin content up to 80%. The calmodulin antagonists chloropromazine and trifluoperazine inhibited the betacyanin accumulation up to 97% when applied at the beginning of the incubation. Neither Co2+ nor trifluoperazine after 12 h of preincubation in kinetin had inhibiting effects on the amaranthin production. Therefore, we presume that a specific period of competence is required for calmodulin-mediated Ca2+ effects on the accumulation of amaranthin induced by cytokinins in the seedlings ofAmaranthus tricolor. 相似文献
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7.
Unimbibed Amaranthus caudatus seeds were found to contain stachyose, raffinose, verbascose, sucrose, galactinol, myo-inositol, glucose and fructose, while no galactose, maltose and maltotriose was detected. During imbibition, seed concentrations
of verbascose, stachyose, raffinose, galactinol, myo-inositol (temporary) and fructose (transient) were observed to decrease; concentrations of galactose and maltose remained
fairly constant, while those of sucrose, glucose and maltotriose increased, the increase in sucrose concentration was only
temporary. Effects of gibberellin A3 (GA3) at 3 × 10−4 M and ethephon at 3 × 10−4 M alone or in the presence of methyl jasmonate (Me-JA) at 10−3 M on concentrations of soluble sugars during germination of A. caudatus seeds were examined. Me-JA was found to inhibit seed germination and fresh weight of the seeds, but did not affect sucrose,
myo-inositol, galactose and maltose concentrations during imbibition for up to 20 h. The exogenously applied GA3 was observed to enhance germination, stachyose breakdown and glucose concentration after 20 h of incubation. Ethephon stimulated
seed germination as well as utilisation of stachyose, galactinol (both after 14 and 20 h) and raffinose (after 14 h of incubation).
Although the stimulatory effect of either GA3 or ethephon on seed germination was blocked by Me-JA; these stimulators increased mobilisation of raffinose and stachyose,
but only ethephon enhanced both glucose and fructose after 14 and/or 20 h of incubation in the presence of Me-JA. The maltose
concentration was increased by both GA3 and ethephon alone and in the presence of Me-JA. Of the growth regulators studied, ethephon alone and/or in combination with
Me-JA significantly increased the concentrations of glucose, fructose, galactose, maltose and maltotriose. The differences
in sugar metabolism appear to be linked to ethylene or GA3 applied simultaneously with Me-JA. 相似文献
8.
Songbei Ying Sasa Jing Leheng Cheng Haiqing Sun Yuan Tian Lulu Zhi Ping Li 《Phyton》2022,91(9):1893-1904
Allantoin as the metabolite of purine catabolism can store and remobilize nitrogen for plant growth and development. However, emerging evidence suggests it also contributes to plant tolerance to stress response through altering abscisic acid (ABA) and reducing reactive oxygen species (ROS) level. 1-CYS PEROXIREDOXIN (PER1) is a seed-specific antioxidant that enhances seed longevity through scavenging ROS over-accumulation. High temperature (HT) suppresses seed germination and induces seed secondary dormancy, called as seed germination thermoinhibition. However, the mechanism that allantoin and PER1 regulate seed germination thermoinhibition remains unknown. In this study, we reported that allantoin treatment enhances seed germination under HT stress. Consistently, the aln mutants displayed higher seed germination, as well as more accumulation of endogenous allantoin, than that of wild-type control. Further biochemical and genetic analyses showed that allantoin reduces ABA content under HT, and allantoin targets PER1 to efficiently scavenge HT-induced ROS accumulation, meanwhile, the function of allantoin requires PER1 during seed gemination thermotolerance. Collectively, our finding proposes a novel function of allantoin in enhancing seed germination tolerance to HT, and uncovers the underlying mechanism by which allantoin regulates seed germination through altering ABA metabolism and PER1-mediated ROS level under HT stress. 相似文献
9.
Nisreen A. AL-Quraan Robert D. Locy Narendra K. Singh 《Plant biotechnology reports》2011,5(3):225-234
Arabidopsis mutants with T-DNA insertion in seven calmodulin genes (CAM) were used to determine the specific role of CAM in the tolerance of plants to oxidative stress induced by paraquat and hydrogen
peroxide (H2O2) treatments. Arabidopsis calmodulin mutants (cam) were screened for seedling growth, seed germination, induced oxidative damage, and levels of γ-aminobutyric acid (GABA)
shunt metabolites. Only the cam5-4 and cam6-1 mutants exhibited an increased sensitivity to paraquat and H2O2 during seed germination and seedling growth. In response to treatments with 3 μM paraquat and 1 mM H2O2, only the cam5-4, cam6-1 mutants showed significant changes in malonaldehyde (MDA) levels in root and shoot tissues, with highly increased levels
of MDA. In terms of the GABA shunt metabolites, GABA was significantly elevated in root and shoot tissues in response to the
paraquat treatments in comparison to alanine and glutamate, while the levels of all shunt metabolites increased in root tissue
but not in the shoot tissue following the H2O2 treatments. GABA, alanine and glutamate levels were significantly increased in root and shoot of the cam1, cam4, cam5-4, and cam6-1 mutants in response to paraquat (0.5, 1 and 3 μM), while they were increased only in the root tissue of the cam1, cam4, cam5-4, and cam6-1 mutants in response to H2O2 (200 and 500 μM, 1 mM). These data show that the cam5-4 and cam6-1 mutants were sensitive to the induced oxidative stress treatments in terms of seed germination, seedling growth, and oxidative
damage. The accumulation of GABA shunt metabolites as a consequence of the induced oxidative stress treatments (paraquat and
H2O2 treatments) suggests that the GABA shunt pathway and the accumulation of GABA metabolites may contribute in antioxidant machinery
associated with reactive oxygen species and in the acquisition of tolerance in response to induced oxidative stress in Arabidopsis seedlings. 相似文献
10.
Sara Mira Elena Estrelles Maria Elena González-Benito Françoise Corbineau 《Acta Physiologiae Plantarum》2011,33(5):1803-1809
The aim of the present study was to determine whether the loss of seed germination capacity and vigour in seeds of four wild
Brassicaceae species (Brassica repanda, Moricandia arvensis, Rorippa nasturtium-aquaticum and Sinapis alba) during ageing at 45°C and 90% relative humidity was related to changes in lipid peroxidation and membrane integrity. For
all of the species, ageing reduced the final germination percentage and increased the length of time required to reach 50%
of final germination (T
50). Large differences in longevity were observed among the species. The times required for viability to be reduced to 80 and
50% of maximum germination (P80 and P50) were the lowest for B. repanda, and these values were two times longer for M. arvensis and R. nasturtium-aquaticum and five times longer for S. alba compared with B. repanda. A loss of seed viability was not associated with malondialdehyde accumulation, suggesting that lipid peroxidation did not
cause seed deterioration under these conditions. However, the conductivity test effectively detected seed deterioration in
these wild Brassicaceae species, and membrane permeability correlated with both germination and vigour loss. This correlation may provide a valuable
mean for early detection of seed viability in wild Brassicaceae species. 相似文献
11.
Xuanyu Liu Zhijun Deng Hongyan Cheng Xinhua He Songquan Song 《Plant Growth Regulation》2011,64(2):155-161
Nitric oxide (NO) and reactive oxygen species (ROS) are important regulators involving various processes of plant growth and
development. Amaranthus retroflexus L. seeds possess a relative dormancy property that means freshly collected seeds can only germinate over a limited, high
temperature range. Here, we show that the relative dormancy of A. retroflexus seeds could be significantly released following treatments with exogenous NO/cyanide (CN) donors such as nitrite, gases evolved
from acidified nitrite, sodium nitroprusside (SNP), potassium ferricyanide (Fe(III)CN) and gases evolved from SNP or Fe(III)CN
solutions, as well as exogenously supplied ROS, hydrogen peroxide (H2O2). However, the effectiveness varied among these chemicals. Gases evolved from acidified nitrite displayed maximum effect
while H2O2 had minimum effect. We also show that the effects of these compounds could be significantly inhibited by NO specific scavenger
2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide (PTIO), indicating that NO signaling pathway might play a central role
in the dormancy release and germination of A. retroflexus seeds, while both ROS and CN might act through NO-dependent signaling cascades. 相似文献
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14.
Glucosamine-6-phosphate (GlcN6P) deaminase seems to be the main enzyme in Aspergillus niger cells responsible for rapid glucosamine accumulation during the early stages of growth in a high-citric-acid-yielding medium.
By determining basic kinetic parameters on the isolated enzyme, a high affinity toward fructose-6-phosphate (Fru6P) was measured,
while in the reverse direction the K
m value for glucosamine-6-phosphate was lower than deaminases from other organisms measured so far. The enzyme characteristics
of GlcN6P deaminase suggest it must compete with 6-phosphofructo-1-kinase (PFK1) for the common substrate—Fru6P in A. niger cells. Glucosamine accumulation seems therefore to remove an intermediate from the glycolytic flux, a situation which is
reflected in slower citric acid accumulation and a specific growth rate after the germination of spores. When ammonium ions
are depleted from the medium, one of the substrates for GlcN6P deaminase becomes limiting and Fru6P can be catabolised by
PFK1 which enhances glycolytic flux. Other enzymatic features of GlcN6P deaminase such as pH optima for both aminating and
deaminating reactions might play a significant role in rapid glucosamine accumulation during the early phase of fermentation
and a slow consumption of aminosugar during the citric-acid-producing phase. 相似文献
15.
16.
In order to investigate the interaction of the plant hormones ethylene, abscisic acid (ABA) and cytokinin in seed germination
and early seedling development, we studied germination in ethylene-related mutants of Arabidopsis. Mutations in the genes etr1 and ein2, which reduce ethylene responses, showed increased dormancy and a delay in germination in comparison with wild type. Mutations
in etr1, ein2 and ein6 also resulted in increased sensitivity to ABA with respect to inhibition of germination. Conversely, mutations in ctr1 and eto3, which lead to an increased ethylene response and overproduction of ethylene, respectively, decreased sensitivity to ABA
during germination. Increased ABA sensitivity was also effected in wild type seeds by the presence during germination of AgNO3, an inhibitor of ethylene action. The addition of the cytokinin N-6 benzyl adenine (BA) reversed the increased sensitivity
of ethylene-resistant mutants to ABA. The action of cytokinin in reversing increased ABA sensitivity of ethylene-resistant
mutants also suggests that at least part of the action of cytokinin in promoting germination is independent of its role in
stimulating ethylene production. These observations further extend the evidence in support of interaction between ethylene,
ABA and cytokinin signalling in controlling seed germination and early seedling development in Arabidopsis. 相似文献
17.
The role of gibberellins (GAs) during germination and early seedling growth is examined by following the metabolism and transport
of radiolabeled GAs in cotyledon, shoot, and root tissues of pea (Pisum sativum L.) using an aseptic culture system. Mature pea seeds have significant endogenous GA20 levels that fall during germination and early seedling growth, a period when the seedling develops the capacity to transport
GA20 from the cotyledon to the shoot and root of the seedling. Even though cotyledons at 0–2 days after imbibition have appreciable
amounts of GA20, the cotyledons retain the ability to metabolize labeled GA19 to GA20 and express significant levels of PsGA20ox2 message (which encodes a GA biosynthesis enzyme, GA 20-oxidase). The large pool of cotyledonary GA20 likely provides substrate for GA1 synthesis in the cotyledons during germination, as well as for shoots and roots during early seedling growth. The shoots
and roots express GA metabolism genes (PsGA3ox genes which encode GA 3-oxidases for synthesis of bioactive GA1, and PsGA2ox genes which encode GA 2-oxidases for deactivation of GAs to GA29 and GA8), and they develop the capacity to metabolize GAs as necessary for seedling establishment. Auxins also show an interesting
pattern during early seedling growth, with higher levels of 4-chloro-indole-3-acetic acid (4-Cl-IAA) in mature seeds and higher
levels of indole-3-acetic acid (IAA) in young root and shoot tissues. This suggests a changing role for auxins during early
seedling development. 相似文献
18.
19.
Identification of a hydrogen peroxide signalling pathway in the control of light-dependent germination in Arabidopsis 总被引:1,自引:0,他引:1
Patricia Lariguet Philippe Ranocha Mireille De Meyer Odile Barbier Claude Penel Christophe Dunand 《Planta》2013,238(2):381-395
Germination is controlled by external factors, such as temperature, water, light and by hormone balance. Recently, reactive oxygen species (ROS) have been shown to act as messengers during plant development, stress responses and programmed cell death. We analyzed the role of ROS during germination and demonstrated that ROS in addition to their role as cell wall loosening factor are essential signalling molecules in this process. Indeed, we showed that ROS are released prior to endosperm rupture, that their production is required for germination, and that class III peroxidases, as ROS level regulators, colocalized with ROS production. Among ROS, H2O2 modifies, during germination early steps, the expression of genes encoding for enzymes regulating ROS levels. This pointing out a regulatory feedback loop for ROS production. Measurements of endogenous levels of ROS following application of GA and ABA suggested that ABA inhibits germination by repressing ROS accumulation, and that, conversely, GA triggers germination by promoting an increase of ROS levels. We followed the early visible steps of germination (testa and endosperm rupture) in Arabidopsis seeds treated by specific ROS scavengers and as the light quality perception is necessary for a regular germination, we examined the germination in presence of exogenous H2O2 in different light qualities. H2O2 either promoted germination or repressed germination depending on the light wavelengths, showing that H2O2 acts as a signal molecule regulating germination in a light-dependent manner. Using photoreceptors null-mutants and GA-deficient mutants, we showed that H2O2-dependent promotion of germination relies on phytochrome signalling, but not on cryptochrome signalling, and that ROS signalling requires GA signalling. 相似文献