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1.
The effects of ABA and GA3 treatments on resistance to frost and high-light treatment in oilseed rape leaf discs 总被引:1,自引:0,他引:1
Marcin Rapacz 《Acta Physiologiae Plantarum》2002,24(4):447-457
The experiments were performed to check the effects of exogenous ABA and gibberellin on photosynthetic apparatus and leaf
resistance to freezing. In the experiment, two cultivars (winter and spring) of oilseed rape were used in the experiment.
Discs, cut out from leaves of cold acclimated plants grown at 12 and 20 °C at similar PPFD levels, were immersed for 72 hours
in growth regulator solutions. Some of discs were additionally subjected to high radiation. Independently on cultivar studied,
the effects of growth regulator treatments were significant only in leaves developed at 20 °C. ABA treatment increased frost
resistance, promoted photosynthetic activity measured in cold and inhibited expansion of leaf-disc area, whereas GA3 evoked opposite effects. The treatment with growth regulators particularly affected the resistance of photosynthetic apparatus
to high light. In this case ABA treatment decreased, whereas GA3 increased photoinhibition of PSII. The outcomes may suggest that in the ABA-treated plants PSII is better protected against
photoinduced inactivation both by the increase in effectiveness of photosynthetic dark reactions at high light/low temperature
conditions, increased energy dissipation in xantophyll cycle and enhanced accumulation of anthocyanins. GA3 treatment may affect the resistance to photoinhibition directly via decrease in anthocyanins contents and indirectly through
increase of elongation growth rate in the tissue. 相似文献
2.
An almost twofold increase in abscisic acid (ABA) content was observed in the leaves of winter oilseed rape plants (Brassica napus L., var. oleifera L., cv. Jantar) grown in the cold (>0°C). This ABA increase took place during the first three days of cold treatment. After 6 days of plant growth in the cold, the level of ABA started to decline or remained constant, depending on the calculation basis: dry weight or disc area units, respectively. The exposure of cold-acclimated plants to night frost (–5°C for 18 h) induced a further increase (65%) in the ABA level, which begun during the first few hours after thawing. The comparison of time courses of frost resistance increments and ABA content changes showed that modifications of ABA level in the cold-treated leaves preceded those of frost resistance, whereas in the frost-pretreated tissues the ABA increase occurred later than that of frost tolerance. Possible interrelations between ABA content, frost tolerance and tissue water potential modifications in the low temperature-affected tissues are discussed. 相似文献
3.
Rhodamine-phalloidin staining of winter oilseed rape suspension cells revealed that the structure of actin cytoskeleton changes
with the phase of cell growth. In small, 4-day-old cells, entering the exponential phase of growth, a dense and uniformly
distributed cortical microfilament networks was seen. In six-day-old vacuolated cells, which reached the stationary phase
of growth, the actin cytoskeleton was composed of thicker microfilament cables in irregular arrangements. In cells acclimated
in cold for 7 days a dense, uniformly distributed and cortical microfilament network was still seen. The fine microfilament
network was sensitive to extracellular freezing since the structures underwent depolymerization at −3 °C (in the presence
of extracellular ice), both in non-acclimated and cold-acclimated cells. The thicker transvacuolar cables in cells of the
stationary growth phase resisted freezing to −7 °C. Acclimation of suspensions at 2 °C resulted in slowing down growth of
cells and in the increased freezing tolerance of cells as indicated by a decrease of LT50 from −11 °C to −17.5o or to −25 °C when determined 7 or 20 days after the beginning of the cold treatment, respectively. Freezing tolerance of
non-acclimated cells decreased from −11 °C to −8 °C during subculture, showing a transient increase to −17 °C on the day 6.
Results indicate that the arrangement of actin microfilaments and their sensitivity to freezing-induced depolymerization depends
on the phase of cell growth rather than on cell acclimation status. Possible mechanisms involved in the freezing-induced depolymerization
of actin microfilaments are discussed.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
4.
Marcin Rapacz 《Acta Physiologiae Plantarum》1998,20(1):67-72
Studies on the effects of temperature during the early stage of growth on frost resistance of winter rape seedlings under
controlled conditions were performed. It was found that cold acclimation responses of plants were affected to a great extent
by the conditions of the seedlings early growth. During this period, when the day temperatures were reduced to the range from
+10 °C to +15 °C, a process termed “prehardening” was observed.
During prehardening plants formed leaf rosettes. Their ability to develop frost resistance during acclimation at +2 °C also
increased. Frost resistance of these plants was comparable with the resistance of plants growing in autumn under field conditions. 相似文献
5.
Abscission probability varies among floral positions within inflorescences of Vicia faba L. Flowers from proximal positions have a greater chance to develop into mature pods than flowers from more distal positions which normally abscise either as older flowers or as young pods. In three field experiments with the indeterminate single stem variety Herz-Freya, changes in the contents of extractable auxins, abscisic acid (ABA) and gibberellins in flowers and pods during their development, and their possible influence on abscission were investigated.Inflorescences at different positions along the stem were divided into the two proximal and the remaining fruits. The content of all three hormones was at a low level during flower development, increased greatly in parallel with dry matter accumulation in the young pods, and then decreased to maturity. The first hormone to increase in the fruits was auxin and this took place when abscission from the distal positions began. ABA and gibberellins at this time were still at a low level. This ontogenic course of hormone production was very similar in fruits of both positions within an inflorescence, but in flowers and young pods from proximal positions, auxin content in most inflorescences was greater than in those from the abscising distal positions. No such positional differences were observed with ABA and gibberellins. Decapitation of the plants reduced flower and pod drop from the remaining reproductive nodes. Although decapitation resulted in less abscission among distal flowers and young pods from these nodes, it did not affect the ontogenic course of auxin and ABA production in these fruits. 相似文献
6.
The aim of the presented methodical experiments was 1) the evaluation if callus of winter oilseed rape (Brassica napus var. oleifera L.) initiates a defence reaction to fungal elicitors: pectinase (polygalacturonase) or chitosan, and 2) the choice of the
elicitor doses, which evoke the strongest tissue reaction. The results obtained will be used in the next experiments relating
the studies of pathogenesis mechanisms proceeding in rape plants infected by necrotrophic fungi. The defence response was
estimated on the basis of changes in electrolyte leakage from cells, metabolic efficiency, phenolic content and catalase activity.
In the experiment pectinase was used at concentration of 3, 8, 16, 133 and 166 μl per 1 cm3 of culture medium while chitosan at: 25, 50, 75 and 100 μg·cm−3. Both elicitors increased cell membrane permeability: pectinase at the doses equal or greater to 16 μl·cm−3 while chitosan of 25 μg·cm−3. The greatest metabolic inefficiency was observed in calli elicited with 16 μl·cm−3 pectinase and with chitosan of 100 μg·cm−3. The decrease in phenolic content was noted under influence of most doses of both elicitors. The highest catalase activity
was evoked by pectinase of 8 μl·cm−3 and chitosan of 75 and 100 μg·cm−3. The results indicated that 8–16 μl·cm−3 of pectinase and 100 μg·cm−3 of chitosan caused the strongest defence reaction of oilseed rape tissue. 相似文献
7.
Recent studies (Rapacz 1999) have shown that cultivars of spring-type oilseed rape are able to cold-acclimate to the level
comparable with winter cultivars, but only after prehardening which results both in the increase of photosynthetic activity
and in growth cessation. It is commonly known that under field conditions spring-type cultivars could not survive winter.
Present studies were undertaken to explain the reasons for low winter hardiness of spring type rape plants. Six cultivars
of spring and two of winter rape were sown in the open-air vegetation room at the end of August.
The obtained results indicate that the degree of frost damage in spring-type plants increased in the course of winter and
this increase was parallel to elongation of generative shoots observed after periods of warming. Each spring cultivar was
completely killed by frost just after its generative shoot reached 15–20 cm, irrespective of its frost resistance level, determined
previously under laboratory conditions. In the case of winter cultivars survival rate was consistent with laboratory-estimated
frost resistance. It is suggested that spring rape could not survive winter because of its limited ability to prevent shoot
elongation during winter at temperatures slightly above 0 °C. It was also found that less efficient photosynthetic electron
transport in autumn was observed in these spring cultivars in which the elongation of generative shoots was observed already
during the first warm break in winter. 相似文献
8.
Characterization and differential expression of dhn/lea/rab-like genes during cold acclimation and drought stress in Arabidopsis thaliana 总被引:16,自引:0,他引:16
We have characterized cDNAs for two new dhn/lea/rab (dehydrin, late embryogenesis-abundant, responsive to ABA)-related genes from Arabidopsis thaliana. The two genes were strongly induced in plants exposed to low temperature (4 °C) and were accordingly designated lti45 and lti30 (low temperature-induced). The lti45 gene product contains the conserved serine stretch and three lysine-rich repeats characteristic of DHN/LEA/RAB proteins and is very similar to another low temperature-responsive protein of A. thaliana, COR47 [17]. Both proteins have the same repeat structure and an overall amino acid identity of 64%. This structural similarity of the proteins and the tandem array of the genes suggest that this gene pair arose through a duplication. The other polypeptide, LTI30, consists of several lysine-rich repeats, a structure found in CAP85, a low temperature-and water stress-responsive protein in spinach [41] and similar proteins found in wheat [20].The expression pattern of the five dhn/lea/rab-related genes (cor47, dhnX, lti30, lti45 and rab18) identified so far in A. thaliana, was characterized in plants exposed to low temperature, drought and abscisic acid (ABA). Expression of both lti30 and lti45 was mainly responsive to low temperature similar to cor47. The lti45 and lti30 genes show only a weak response to ABA in contrast to cor47, which is moderately induced by this hormone. The three genes were also induced in severely water-stressed plants although the expression of lti30 and lti45 was rather low. In contrast to these mainly low temperature-induced genes, the expression of rab18 was strongly induced both in water-stressed and ABA-treated plants but was only slightly responsive to cold. The dhnX gene showed a very different expression pattern. It was not induced with any of the treatments tested but exhibited a significant constitutive expression. The low-temperature induction of the genes in the first group, lti30 and lti45, is ABA-independent, deduced from experiments with the ABA-deficient (aba-1) and ABA-insensitive (abi1) mutants of A. thaliana, whereas the induction of rab18 is ABA-mediated. The expression of dhnX was not significantly affected in the ABA mutants. 相似文献
9.
Cold-deacclimation of oilseed rape (Brassica napus var. oleifera) in response to fluctuating temperatures and photoperiod 总被引:2,自引:0,他引:2
Rapacz M 《Annals of botany》2002,89(5):543-549
The aim of this work was to establish the role of factors that may trigger elongation growth in the dehardening response, namely temperature during daylight, photoperiod and vernalization. Fully cold-acclimated seedlings of winter (with incomplete vernalization) and spring oilseed rape were subjected to deacclimation under temperatures of 2/12, 12/2, 12/12, 12/20, 20/12 and 20/20 degrees C (day/night) and a 12 h photoperiod. Plants were also deacclimated under photoperiods of 8 and 16 h at constant temperatures of 12 and 20 degrees C. After deacclimation, plants were subjected to reacclimation. Results suggest that the level of growth activity induced during deacclimation affects both the deacclimation rate and the capacity for reacclimation. Deacclimation is fully reversible if it is not accompanied by induction of elongation growth. In such cases the rate of the decrease in freezing tolerance depends on the mean temperature of deacclimation. Deacclimation becomes partially or completely irreversible when it is connected with promotion of elongation growth. The stimuli triggering elongation growth during deacclimation may be the growth-promoting temperature (20 degrees C) during the day and the lack of vernalization blockage of elongation growth. When elongation growth was stimulated by other factors such as long-day treatments, rehardening was also disturbed. 相似文献
10.
11.
Nitrogen and fungicide applications against Erysiphe cruciferarum affect quality components of oilseed rape 总被引:1,自引:0,他引:1
Oilseed rape (Brassica napus L.) is one of the most important oilseed crops in temperate climates. Erysiphe cruciferarum is an important disease of oilseed rape and causes crop loss in warmer areas of Europe. The research investigated the effect
of nitrogen fertilizer and fungicidal treatment against powdery mildew infection caused by E.
cruciferarum of oilseed rape on seed components, including protein, oil, oleic acid, linolenic acid and undesirable substances such as
sinapic acid esters (SAE) and glucosinolates (GSL), using near infrared spectroscopy (NIRS). Five susceptible oilseed rape
varieties were employed in this research using four treatment groups: no nitrogen fertilization and no fungicidal treatment
(N0–F0); no nitrogen fertilization but fungicidal treatment (N0–F1); and nitrogen fertilization but no fungicidal treatment (N1–F0); nitrogen fertilization and fungicidal treatment (N1–F1). Nitrogen fertilization increased the protein, but lowered the oil content, of the seeds. Fungicidal treatments significantly
increased oil contents in all varieties tested, however reduced protein levels in fertilized and non-fertilized plots. The
level of linolenic acid did not change significantly in any plots of any treatment combinations; a similar result was observed
in the level of oleic acid in most of the genotypes. Nitrogen fertilization increased GSL and SAE levels, whereas fungicidal
treatment had no effect. Our findings demonstrated that nitrogen fertilization can markedly influence some quality parameters
in oilseed rape; however, the application of fungicides reduced side effects of nitrogen fertilizer and resulted a reduction
on GSL, SAE and protein contents but an increase on total oil and oleic acid contents. 相似文献
12.
13.
14.
Genetic manipulation in cultivars of oilseed rape (Brassica napus) using Agrobacterium 总被引:1,自引:0,他引:1
G. Ooms A. Bains M. Burrell A. Karp D. Twell E. Wilcox 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1985,71(2):325-329
Summary The response of oilseed rape cultivars to infection with Agrobacterium tumefaciens and A. rhizogenes and the possibility of regenerating genetically transformed oilseed rape plants were examined. The frequency at which Agrobacterium induced galls or hairy-roots on in vitro cultured plants ranged from 10% to 70%, depending on the cultivar. From galls induced by the tumorigenic strain T37, known to be strongly shoot inducing on tobacco, roots developed frequently. Occasionally, shoots formed and some of these produced tumour cell specific nopaline. Attempts to grow the transformed shoots into plants have so far been unsuccessful. Whole plants transformed with Ri-T-DNA, however, were regenerated. These had crinkled leaves and abundant, frequently branching roots that showed reduced geotropism, similar to previously isolated Ri T-DNA transformed tobacco and potato plants. The transformed oilseed rape plants flowered, but failed to form seeds. 相似文献
15.
We have isolated a rab-related (responsive to ABA) gene, rab18 from Arabidopsis thaliana. The gene encodes a hydrophilic, glycine-rich protein (18.5 kDa), which contains the conserved serine- and lysine-rich domains characteristic of similar RAB proteins in other plant species. The rab18 mRNA accumulates in plants exposed to low temperature, water stress or exogenous ABA but not in plants subjected to heat shock. This stress-related accumulation of the rab18 mRNA is markedly decreased in the ABA-synthesis mutant aba-1, the ABA-response mutant abi-1 or in wild-type plants treated with the carotenoid synthesis inhibitor, fluridone. Exogenous ABA treatment can induce the rab18 mRNA in the aba-1 mutant but not in the abi-1 mutant. These results provide direct genetic evidence for the ABA-dependent regulation of the rab18 gene in A. thaliana. 相似文献
16.
Plant development from microspore-derived embryos in oilseed rape as affected by chilling, desiccation and cotyledon excision 总被引:1,自引:0,他引:1
The present study evaluated the effects of chilling, partial desiccation, cotyledon excision and successive subculture of
microspore-derived embryos on plant development in oilseed rape (Brassica napus L.). The results showed that out of the five media, all the genotypes showed the best response when the embryos were cultured
on the half-strength Murashige and Skoog medium with 2.0 mg dm−3 benzylaminopurine. A cold treatment for 3 or 5 d further increased frequencies of embryo germination (90.0 %) and plantlet
development (58.46 %). Desiccation for one day also increased the embryo germination and plantlet development in all genotypes
tested. Cutting the cotyledons of the embryos at late cotyledonary stage significantly increased the frequency of plantlet
development. The highest rate of plantlet development was obtained from cultures of embryos sampled with size of less than
4.0 mm. The successive subculture further improved the germination and development of plantlets from embryos. In the genotype
ZJU452, the rate of plantlet development reached 99.78 % after the second subculture of embryos. 相似文献
17.
Foliar treatment of oilseed rape plants (Brassica napus L.ssp. napus cv. Linetta) with the growth retardant BAS 111..W at the 5th leaf stage delayed pod senescence during early maturation. Changes of immunoreactive cytokinin- and abscisic acid (ABA)- like substances and of the ethylene precursor 1-aminocyclo-propane-1-carboxylic acid (ACC) and its malonyl-conjugate (MACC) were determined in intact whole pods. When compared with control plants, higher levels of total chlorophyll correlated with four-fold and three-fold increases of trans-zeatin riboside- and dihydrozeatin riboside-type cytokinins, respectively, in the pods of plants treated with 0.25 mg BAS 111..W per plant. Isopentenyladenosine-type cytokinins and ACC and MACC contents remained virtually unchanged, whereas ABA levels dropped considerably below those of controls (60% reduction). However, when analysed at late pod maturity, BAS 111..W treatment no longer affected the total chlorophyll content, or the levels of cytokinins, ABA, ACC and MACC. We hypothesize that the retardant-induced changes in the hormonal status of the pods, favouring the senescence-delaying cytokinins as opposed to abscisic acid, could contribute to the developmental delay. 相似文献
18.
19.
León A. Bravo Gustavo E. Zúñiga Miren Alberdi Luis J. Corcuera 《Physiologia plantarum》1998,103(1):17-23
The role of ABA in freezing resistance in nonacclimated and cold‐acclimated barley ( Hordeum vulgare L.) was studied. Eleven nonacclimated cultivars differed in their LT50 , ranging from −10.8 to −4.8°C. Sugars, free proline, soluble proteins and ABA were analyzed in nonacclimated cultivars and during cold acclimation of one cultivar. There was an inverse correlation between LT50 and both ABA and sucrose contents. Exogenous ABA caused a decrease in the freezing point of leaf tissue in the cultivar with the lowest level of endogenous ABA, but not in the cultivar with the highest level, suggesting that ABA in the latter may be near the optimum endogenous level to induce freezing tolerance. Plants of cv. Aramir treated with ABA or allowed to acclimate to cold temperature increased their soluble sugar content to a similar level. The LT50 of leaves of cold‐acclimated cv. Aramir decreased from −5.8 to −11.4°C, with biphasic kinetics, accumulating proline and soluble sugars with similar kinetics. The biphasic profile observed during cold acclimation could be a direct consequence of cryoprotectant accumulation kinetics. ABA and soluble protein accumulation showed a single step profile, associated mainly with the second phase of the LT50 decrease. Thus, a significant increase in endogenous ABA is part of the response of barley to low temperature and may be required as a signal for the second phase of cold acclimation. Endogenous ABA contents in the nonacclimated state may determine constitutive freezing tolerance. 相似文献
20.
Stephen R. Millam Alan T. H. Burns Trevor J. Hocking Ken J. Cattell 《Plant Cell, Tissue and Organ Culture》1988,12(3):285-290
A method is described for regenerating callus from mesophyll protoplasts of a winter variety of Brassica napus. The method combines the use of Ficoll in an initial liquid medium, enhancing early protoplast division and cell colony formation, with a transfer to an agarose system after 10 days culture to give rapid microcalli formation. Further transfers resulted in callus regeneration and the initiation of organogenesis. 相似文献