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1.
Stornata of leaves of non-stressed yellow lupin plants wereclosed with phenylmercuric acetate (PMA) and viscous flow resistanceand apparent diffusive resistance were measured for both leafsurfaces. Viscous flow resistance was proportional to the ythpower of apparent diffusive resistance with y = 1.19 ±0.10 for the upper surface and y = 1.58 ± 0.11 for thelower surface, i.e. viscous flow resistance changed faster thanapparent diffusive resistance. However, in three separate experiments where lupin plants werewatered with 104 M abscisic acid (ABA) for 1 week, they values were between 0.29 and 0.59 for the upper surface andbetween 0.18 and 1.00 for the lower surface. Similarly, drought-hardened plants showed y values between 0.45and 0.52 for the upper surface, and between 0.43 and 0.88 forthe lower surface. Both ABA. and drought-induced changes iny values were statistically different from PMA results at the1% confidence level. Upon rewatering, drought-stressed plants and ABA-treated plantsrecovered within 2 and 5 d respectively. Thus with both treatments there was a considerable increasein apparent diffusive resistance (and thus a decrease in transpiration)which could not be accounted for by a comparable increase inviscous flow resistance (i.e. stomatal closure). These results suggest that drought stress and ABA treatmentcause an extrastomatal resistance to transpiration in the leavesof yellow lupin plants. 相似文献
2.
Drought Induces Oxidative Stress and Enhances the Activities of Antioxidant Enzymes in Growing Rice Seedlings 总被引:7,自引:0,他引:7
When rice seedlings grown for 10 and 20 days were subjected to in vitro drought stress of −0.5 and −2.0 MPa for 24 h, an increase in the concentration of superoxide anion (O2.−), increased level of lipid peroxidation and a decrease in the concentration of total soluble protein and thiols was observed
in stressed seedlings compared to controls. The concentration of H2O2 as well as ascorbic acid declined with imposition of drought stress, however glutathione (GSH) concentration declined only
under severe drought stress. The activities of total superoxide dismutases (SODs) as well as ascorbate peroxidase (APX) showed
consistent increases with increasing levels of drought stress, however catalase activity declined. Mild drought stressed plants
had higher guaiacol peroxidase (GPX) and chloroplastic ascorbate peroxidase (c-APX) activity than control grown plants but
the activity declined at the higher level of drought stress. The activities of enzymes involved in regeneration of ascorbate
i.e. monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR) and glutathione reductase (GR) were higher
in drought stressed plants compared to controls. Results suggest that drought stress induces oxidative stress in rice plants
and that besides SOD, the enzymes of ascorbate-glutathione cycle, which have not been studied in detail earlier under stressful
conditions, appear to function as important component of antioxidative defense system under drought stress. 相似文献
3.
Yongan Zhang Qinghua Wang Xue Zhang Xingliang Liu Ping Wang Yuxia Hou 《Journal of Plant Biology》2011,54(5):303-313
4.
Yiming Zhang Jinfen Yang Shaoyun Lu Jiongliang Cai Zhenfei Guo 《Journal of Plant Growth Regulation》2008,27(2):151-158
Abscisic acid (ABA) regulates plant adaptive responses to various environmental stresses. 9-cis-epoxycarotenoid dioxygenase (NCED) is the key enzyme of ABA biosynthesis in higher plants. A NCED gene, SgNCED1, was overexpressed in transgenic tobacco plants which resulted in 51–77% more accumulation of ABA in leaves. Transgenic tobacco
plants decreased stomatal conductance, transpiration rate, and photosynthetic rate but induced activities of superoxide dismutase
(SOD), catalase (CAT), and ascorbate-peroxidase (APX). Hydrogen peroxide (H2O2) and nitric oxide (NO) in leaves were also induced in the transgenic plants. Compared to the wild-type control, the transgenic
plants improved growth under 0.1 M mannitol-induced drought stress and 0.1 M NaCl-induced salinity stress. It is suggested
that the ABA-induced H2O2 and NO generation upregulates the stomatal closure and antioxidant enzymes, and therefore increases drought and salinity
tolerance in the transgenic plants. 相似文献
5.
6.
To elucidate the role of the plant hormones—abscisic acid (ABA) and ethylene during flower senescence in roses, experiments
were conducted on two cultivars of cut-roses (Rosa hybrida L.), ‘Grandgala’ and ‘First Red,’ obtained from a commercial grower. An apparent similarity was observed during flower senescence
and accumulation of endogenous ABA in petal tissue. Several fold increase in ABA concentration was observed during the later
stages of senescence which was found to be associated with a drastic reduction of flower water potential and water uptake.
During the later stages of senescence (S5–S6) higher ABA concentration coincides with the elevated concentration of ethylene
production. ABA and ethylene both stimulate senescence and are suggested to interact during flower senescence under water
limitations. 相似文献
7.
Summary A pot-culture experiment was undertaken to assess the physiological significance of ascorbic acid in relation to drought resistance
in two high-yielding varieties of rice — Taichung Native — 1 and I.R. 8. The soil-moisture stresses were maintained at 7–10
and 15–20 per cent moisture at field capacity. The wilting treatments were given only at tillering and shooting stages. Observations
pertaining to survivality of rice plants and determinations of ascorbic acid, acorbigen and ascorbic acid utilization in fresh
leaves were made.
The two varieties of rice,i.e. Taichung Native-1 and I.R. 8 were not identical in their drought tolerance. Taichung Native-1 was more drought resistant
which may be presumed in view of their differences in morphological make-up and demand for water at different stages of growth.
The leaves of Taichung Native-1 showed greater contents of ascorbic acid and ascorbigen following increased rate of ascorbic
acid utilization as compared to I.R. 8. These values were significantly reduced during shooting stage, a critical period to
drought. This confirms the significance of ascorbic acid towards drought resistance in plants with special reference to rice. 相似文献
8.
Metabolic pathways regulated by abscisic acid,salicylic acid and γ‐aminobutyric acid in association with improved drought tolerance in creeping bentgrass (Agrostis stolonifera) 下载免费PDF全文
Abscisic acid (ABA), salicylic acid (SA) and γ‐aminobutyric acid (GABA) are known to play roles in regulating plant stress responses. This study was conducted to determine metabolites and associated pathways regulated by ABA, SA and GABA that could contribute to drought tolerance in creeping bentgrass (Agrostis stolonifera). Plants were foliar sprayed with ABA (5 μM), GABA (0.5 mM) and SA (10 μM) or water (untreated control) prior to 25 days drought stress in controlled growth chambers. Application of ABA, GABA or SA had similar positive effects on alleviating drought damages, as manifested by the maintenance of lower electrolyte leakage and greater relative water content in leaves of treated plants relative to the untreated control. Metabolic profiling showed that ABA, GABA and SA induced differential metabolic changes under drought stress. ABA mainly promoted the accumulation of organic acids associated with tricarboxylic acid cycle (aconitic acid, succinic acid, lactic acid and malic acid). SA strongly stimulated the accumulation of amino acids (proline, serine, threonine and alanine) and carbohydrates (glucose, mannose, fructose and cellobiose). GABA enhanced the accumulation of amino acids (GABA, glycine, valine, proline, 5‐oxoproline, serine, threonine, aspartic acid and glutamic acid) and organic acids (malic acid, lactic acid, gluconic acid, malonic acid and ribonic acid). The enhanced drought tolerance could be mainly due to the enhanced respiration metabolism by ABA, amino acids and carbohydrates involved in osmotic adjustment (OA) and energy metabolism by SA, and amino acid metabolism related to OA and stress‐defense secondary metabolism by GABA. 相似文献
9.
Changes in antioxidant enzymes activity and oxidative stress by abscisic acid and salicylic acid in wheat genotypes 总被引:9,自引:0,他引:9
Abscisic acid (ABA) and salicylic acid (SA) were sprayed on leaves of wheat genotypes C 306 and Hira at 25 and 40 d after sowing under moderate water stress (−0.8 MPa) imposed by adding PEG-6000 in nutrient solution. ABA and SA increased the activities of superoxide dismutase, ascorbate peroxidase, glutathione reductase, and catalase in comparison to unsprayed control plants. Both ABA and SA treatments decreased the contents of hydrogen peroxide and thiobarbituric acid reactive substances, a measure of lipid peroxidation, compared to unsprayed plants. The beneficial effect of increase in antioxidant enzymes activity and decrease in oxidative stress was reflected in increase in chlorophyll and carotenoid contents, relative water content, membrane stability index, leaf area and total biomass over control plants. The lower concentrations of ABA (0.5 mM) and SA (1.0 mM) were generally more effective than higher concentrations. 相似文献
10.
Mokhtar Guerfel Alexandros Beis Tasos Zotos Dalenda Boujnah Mokhtar Zarrouk Angelos Patakas 《Acta Physiologiae Plantarum》2009,31(4):825-831
Differences in abscisic acid (ABA) accumulation between two olive cultivars were studied by enzyme-linked immunosorbent assay
in roots and leaves, leaf water potential (Ψl), stomatal conductance (g
s) as well as photosynthetic rate (A) were also determined in well-watered (WW) and water-stressed (WS) plants of two olive
cultivars ‘Chemlali’ and ‘Chetoui’. ‘Chemlali’ was able to maintain higher leaf CO2 assimilation rate and leaf stomatal conductance throughout the drought cycle when compared with ‘Chetoui’. Furthermore, leaf
water potential of ‘Chemlali’ decreased in lower extent than in Chetoui in response to water deficit. Interestingly, significant
differences in water-stress-induced ABA accumulation were observed between the two olive cultivars and reflect the degree
of stress experienced. Chemlali, a drought tolerant cultivar, accumulated lower levels of ABA in their leaves to regulate
stomatal control in response to water stress compared to the drought sensitive olive cultivar ‘Chetoui’ which accumulated
ABA in large amount. 相似文献
11.
To explore the significance of the ascorbate–glutathione cycle under drought stress, the leaves of 2-year-old potted apple
(Malus domestica Borkh.) plants were used to investigate the changes of each component of the ascorbate–glutathione cycle as well as the gene
expression of dehydroascorbate reductase (DHAR, EC 1.8.5.1), ascorbate peroxidase (APX, EC 1.11.1.11) and glutathione reductase
(GR, EC 1.6.4.2) under drought stress. The results showed that the malondialdehyde (MDA) and H2O2 concentrations in apple leaves increased during drought stress and began to decrease after re-watering. The contents of total
ascorbate, reduced ascorbic acid (AsA), total glutathione and glutathione (GSH) were obviously upregulated in apple leaves
when the soil water content was 40–45%. With further increase of the drought level, the contents of the antioxidants and especially
redox state of AsA and GSH declined. However, levels of them increased again after re-watering. Moreover, drought stress induced
significant increase of the activities of enzymes such as APX, scavenging H2O2, and also of monodehydroascorbate reductase (MDHAR, EC 1.6.5.4), DHAR and GR used to regenerate AsA and GSH, especially when
the soil water content was above 40–45%. During severe drought stress, activities of the enzymes were decreased and after
re-watering increased again. Gene expression of cytoplasmic DHAR, cytoplasmic APX and cytoplasmic GR showed similar changes as the enzyme activities, respectively. The results suggest that the ascorbate–glutathione cycle is
up-regulated in response to drought stress, but cannot be regulated at severe drought stress conditions. 相似文献
12.
13.
M. Jain A. S. Nandwal B. S. Kundu B. Kumar I. S. Sheoran N. Kumar A. Mann S. Kukreja 《Biologia Plantarum》2006,50(2):303-306
The plants of pigeonpea (Cajanus cajan L.) cv. H77-216 were subjected to moderate [soil moisture content (SMC) = 7.3 ± 0.5 %] and severe (SMC = 4.3 ± 0.5 %) drought
by withholding the irrigation at vegetative stage (45 d after sowing). The control plants were maintained at SMC of 11.0 ±
0.5 %. Half of the stressed plants were re-irrigated and their recovery was studied after 2 d. Leaf water potential, osmotic
potential, and relative water content of leaf and root decreased significantly while a sharp rise in proline and total soluble
sugars contents were noticed. Drought induced a significant increase in 1-aminocyclopropane 1-carboxylic acid (ACC) content
and ACC oxidase activity which caused a considerable increase in ethylene evolution. Malondialdehyde content and relative
stress injury were increased under drought whereas reverse was true for ascorbic acid content. The membrane integrity of roots
decreased during stress and recovered on rehydration. The specific activity of total superoxide dismutase, ascorbate peroxidase,
glutathione reductase, and glutathione transferase decreased to 37 – 78 %, 17 – 62 %, 29 – 36 % and 57 – 79 % at moderate
and severe drought, respectively. The increase in activity of catalase and peroxidase could not overcome the accumulation
of H2O2 content in the roots. 相似文献
14.
Jalel Mahouachi Rosa Argamasilla Aurelio Gómez-Cadenas 《Journal of Plant Growth Regulation》2012,31(1):1-10
The effects of exogenous foliar glycine betaine (GB) and abscisic acid (ABA) on papaya responses to water stress were investigated
under distinct water regimes. Papaya seedlings (Carica papaya L. cultivar “BH-65”) were pretreated with GB or ABA and subsequently subjected to consecutive periods of drought, rehydration,
and a second period of drought conditions. Results indicated that water stress induced ABA, jasmonic acid (JA), and proline
accumulation but did not modify malondialdehyde (MDA) concentration. In addition, water deprivation reduced photosynthetic
rate, stomatal conductance, relative water content (RWC), leaf fresh weight, and increased leaf abscission. GB applied prior
to drought imposition decreased the impact of water stress on ABA, JA, proline accumulation, leaf water status, growth, and
photosynthetic performance. However, ABA-pretreated plants did not show alteration of most of these parameters under water
stress conditions when compared with non-pretreated plants except a clear induction of JA accumulation. Taken together, the
data suggest that GB may modulate ABA, JA, and proline accumulation through the control of stomatal movement and the high
availability of compatible solutes, leading to improvement of leaf water status, growth, and photosynthetic machinery function.
In contrast, exogenous ABA did not stimulate papaya physiological responses under drought, but interestingly ABA in combination
with drought could induce progressive JA synthesis, unlike drought alone, which induces a transitory JA increase and may trigger
endogenous ABA accumulation. The data also suggest that irrespective of the pretreatments, papaya did not suffer oxidative
damage. 相似文献
15.
A laboratory study was undertaken to ascertain the impact and the extent of feeding by different pests on biochemical constituents
and various enzyme levels in rice plants. The difference in these parameters due to the pest damage by three different modes
of feeding was also studied and compared. The borer pest—yellow stem borer (YSB), Scirpophaga incertulas (W); surface feeder—-leaf roller (LR), Cnaphalocrosis medinalis (G) and a sucking pest—brown plant hopper (BPH), Nilaparvata lugens (S) fed rice plants were analyzed for the quantitative and qualitative changes in biochemical profile and enzymatic changes
that occur as plant’s defensive responses were analyzed spectrophotometrically. The phenolic acids were analyzed using HPLC
and quantitated with the standard samples. The quantity of biochemicals such as proteins, phenols and carbohydrates has been
enhanced along with the enzyme activities of peroxidase (POD), catalase (CAT), chitinase (CHI). A decrease in superoxide dismutase
(SOD), phenyl alanine ammonia lyase (PAL), β-1, 3-glucanase (GLU) enzyme activities were evident in pest infested plants.
Phenolic acids like vanillic acid, syringic acid, cinnamic acid, and p-coumaric acids were mostly found in the infested plants. We demonstrate that the elevated levels of biochemicals, phenolic
acids, and enzymes may play a major role in plant defense. 相似文献
16.
The objective of this work was to test whether Ca2+, a second messenger in stress response, is involved in ABA-induced antioxidant enzyme activities in Stylosanthes guianensis. Plants were sprayed with abscisic acid (ABA), calcium channel blocker, LaCl3, calcium chelator, ethylene glycol-bis(β-amino ethyl ether)-N,N,N′, N′-tetraacetid acid (EGTA), and ABA in combination with LaCl3 or EGTA. Their effects on superoxide dismutase (SOD) and ascorbate peroxidase (APX) activities and chilling resistance were
compared. The results showed that ABA decreased electrolyte leakage and lipid peroxidation but increased maximum photochemical
efficiency measured as variable to maximum fluorescence ratio (Fv/Fm) under chilling stress. Treatment with LaCl3 or EGTA alone and in combination with ABA increased electrolyte leakage and lipid peroxidation, decreased Fv/Fm, suggesting
that the block in Ca2+ signalling decreased chilling resistance of S. guianensis and the ABA-enhanced chilling resistance. ABA-induced SOD and APX activities were suppressed by LaCl3 or EGTA. The results suggested that Ca2+ is involved in the ABA-enhanced chilling resistance and the ABA-induced SOD and APX activities in S. guianensis. 相似文献
17.
New Plant Growth Regulators Protect Photosynthesis and Enhance Growth Under Drought of Jack Pine Seedlings 总被引:12,自引:0,他引:12
To determine whether natural plant growth regulators (PGRs) can enhance drought tolerance and the competitive ability of
transplanted seedlings, 1.5-year-old jack pine (Pinus banksana Lamb.) seedlings were treated with homobrassinolide, salicylic acid, and two polyamines, spermine and spermidine, triacontanol,
abscisic acid (ABA), and the synthetic antioxidant, Ambiol. PGRs were fed into the xylem for 7 days and plants were droughted
by withholding water for 12 days. ABA, Ambiol, spermidine, and spermine at a concentration of 10 μg L−1 stimulated elongation growth under drought, whereas ABA, Ambiol, and spermidine maintained higher photosynthetic rates, higher
water use efficiency, and lower Ci/Ca ratio under drought compared with control plants. The damaging effects of drought on
membrane leakage was reversed by Ambiol, ABA, triacontanol, spermidine, and spermine. Because ABA, Ambiol, and both polyamines
enhanced elongation growth and also reduced membrane damage in jack pine under drought, they show promise as treatments to
harden seedlings against environmental stress. The protective action of these compounds on membrane integrity was associated
with an inhibition of ethylene evolution, with a reduction in transpiration rate and an enhancement of photosynthesis, which
together increased water use efficiency under drought. Although most of the tested compounds acted as antitranspirants, the
inhibition in membrane leakage in ABA-, Ambiol-, and polyamine-treated plants appeared more closely related to the antiethylene
action.
Received December 30, 1998; accepted October 14, 1999 相似文献
18.
The aims of the present study are to find out whether the effects of arbuscular mycorrhizal (AM) symbiosis on plant resistance
to water deficit are mediated by the endogenous abscisic acid (ABA) content of the host plant and whether the exogenous ABA
application modifies such effects. The ABA-deficient tomato mutant sitiens and its near-isogenic wild-type parental line were used. Plant development, physiology, and expression of plant genes expected
to be modulated by AM symbiosis, drought, and ABA were studied. Results showed that only wild-type tomato plants responded
positively to mycorrhizal inoculation, while AM symbiosis was not observed to have any effect on plant development in sitiens plants grown under well-watered conditions. The application of ABA to sitiens plants enhanced plant growth both under well-watered and drought stress conditions. In respect to sitiens plants subjected to drought stress, the addition of ABA had a cumulative effect in relation to that of inoculation with G. intraradices. Most of the genes analyzed in this study showed different regulation patterns in wild-type and sitiens plants, suggesting that their gene expression is modulated by the plant ABA phenotype. In the same way, the colonization
of roots with the AM fungus G. intraradices differently regulated the expression of these genes in wild-type and in sitiens plants, which could explain the distinctive effect of the symbiosis on each plant ABA phenotype. This also suggests that
the effects of the AM symbiosis on plant responses and resistance to water deficit are mediated by the plant ABA phenotype. 相似文献
19.
Heat shock protein 70 regulates the abscisic acid-induced antioxidant response of maize to combined drought and heat stress 总被引:1,自引:0,他引:1
Xiuli Hu Ruixia Liu Yanhui Li Wei Wang Fuju Tai Ruili Xue Chaohai Li 《Plant Growth Regulation》2010,60(3):225-235
We investigated the interaction between heat shock protein 70 (HSP70) and abscisic acid (ABA)-induced antioxidant response
of maize to the combination of drought and heat stress. First, the increased activities of enzymes, including superoxide dismutase
(SOD), ascorbate peroxidase (APX), glutathione reductase (GR) and catalase (CAT), induced by drought were less than those
by heat or combined drought and heat stress, except some individual cases (e.g. CAT in leaves, GR in roots). Second, both
HSP70 synthesis and H2O2 production increased prominently under drought, heat or their combination stress; the increase in leaves induced by drought
and heat combination was the highest, followed by heat and by drought, while the increase in roots had not visible difference.
Third, either in leaves or roots, pretreatment with ABA inhibitor, HSP70 inhibitor and H2O2 scavenger, significantly arrested the stress-induced increase of antioxidant enzyme activities, and ABA inhibitor and H2O2 scavenger obviously suppressed HSP70 synthesis, while HSP70 inhibitor slightly heightened H2O2 accumulation. Finally, 100 μM ABA significantly enhanced the activities of antioxidant enzymes, HSP70 expression and H2O2 production under stresses in comparison with ABA-deficient mutant vp5 maize plants without pretreatment. Thus, ABA-induced H2O2 production enhances the HSP70 synthesis and up-regulates the activities of antioxidant enzymes, resulting in the suppression
of cellular reactive oxygen species (ROS) levels. Our results suggest that HSP70 may play a crucial role in ABA-induced antioxidant
defense of maize to drought and heat combination. 相似文献