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1.
An intensive understanding of vacuum infiltration transformation of pakchoi (Brassica rapa ssp. chinensis) 总被引:1,自引:0,他引:1
Pakchoi (Brassica rapa L. ssp. chinensis), a kind of Chinese cabbage, is an important vegetable in Asian countries. Agrobacterium mediated in planta vacuum infiltration transformation has been performed in pakchoi since 1998, but a detailed study on this technique was lacking. Pakchoi plants 40-50 days old with inflorescences were vacuum infiltrated with Agrobacterium tumefaciens strain C58C1 harboring the binary vector pBBBast-gus-intron. The transformation frequency in the harvested seeds mainly varied from 1 x 10(-4) to 3 x 10(-4) over several years, and it was lower than the frequency in Arabidopsis thaliana. Transformants were obtained from both the upper and the lower parts of the infiltrated plants with or without an elongated inflorescence. Stained ovules and pollen grains were found in the unopened flower 13 days post-infiltration, which was about 0.5-1 mm in diameter at infiltration time with an open ovary as revealed by paraffin sections. Histochemical assays revealed that Agrobacteria were more abundant in the flower tissue than in stem and leaf tissues at all times after infiltration despite the sharp decrease of live Agrobacteria in plant 14 days post infiltration as revealed by the colony forming units on the Agrobacteria culture medium. The results of vacuum infiltration transformation of pakchoi and Arabidopsis thaliana were compared and a strategy to optimize the transformation conditions to increase the transformation frequency in pakchoi was discussed. 相似文献
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3.
Agrobacterium-mediated genetic transformation is the most widely used technology to obtain overexpression of recombinant proteins in plants.
Molecular events that occur within Agrobacterium during interactions with host plants have been studied extensively, and now we have a reasonable understanding the key factors
involved in the regulation of T-DNA nuclear import and genomic integration. By contrast, very little is known about the events
that take place in the host cells during genetic transformation by Agrobacterium. Here, we describe the plant-related factors including genotype, genes, proteins, competency of target tissues and phenolic
compounds that participate in Agrobacterium-mediated genetic transformation and discuss their possible roles in this process. Because Agrobacterium probably adapts existing cellular processes for its life cycle, identifying the processes in host cells during Agrobacterium infection might contribute to better understanding of basic biological processes as cell communication, intracellular transport
and DNA repair and recombination as well as to expanding the host range of Agrobacterium as a genetic engineering tool. 相似文献
4.
Hairy roots of Plumbago indica were established at high frequency (90 %) by infecting leaf explants with Agrobacterium rhizogenes strain ATCC 15834. The axenic root cultures were established under darkness in hormone-free liquid Murashige and Skoog medium
containing 3 % sucrose. The highest plumbagin content was found to accumulate in roots at their exponential phase of growth.
A low pH (4.6) and a low concentration of sucrose (1 %) were beneficial for root growth in darkness, while pH 5.6 and 3 %
sucrose under continuous irradiance enhanced plumbagin accumulation in roots up to 7.8 mg g−1(d.m.). Direct shoot regeneration from hairy root culture was also achieved under continuous irradiance, thus indicated an
easy way of obtaining transformed P. indica plants. 相似文献
5.
We have investigated the effects of cadmium on the microtubular (MT) cytoskeleton in the root tip cells of Allium sativum L. using indirect immunofluorescence microscopy. Cd affected the mechanisms controlling the organization of MT cytoskeleton,
as well as tubulin assembly/disassembly processes. Cd induced the formation of abnormal MT arrays, consisting of discontinuous
wavy MTs or short MT fragments at the cell periphery. Cadmium caused irregular nuclear disorder in cells where the MT organization
and function was disturbed. Furthermore, with increased Cd concentration and duration of treatment the MTs depolymerized more
severely, the frequency of abnormal cell increased and the mitotic index decreased progressively. The above findings showed
that MT cytoskeleton is one of target sites of Cd toxicity in root tip cells. 相似文献
6.
Single-stranded DNA-binding proteins form protective caps at the chromosome ends and their binding is important in the regulation
of telomerase access to telomeres. This group of proteins is represented by POT1 proteins described in yeast, humans and other
model organisms. Here we review recent findings obtained in Arabidopsis POT1-like paralogs, namely the observed diversity in their interaction features and corresponding functions. 相似文献
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8.
A. I. Cordeiro J. F. Sanchez-Sevilla M. C. Alvarez-Tinaut M. C. Gomez-Jimenez 《Biologia Plantarum》2008,52(4):642-647
Eighty seven olive (Olea europaea ssp. sativa L.) cultivar accessions from Portugal were characterized by means of randomly amplified polymorphic DNA (RAPD) markers. Of
the 11 arbitrary 10-mer primers tested a total of 92 polymorphic bands were obtained, representing 87.6 % of the total amplification
products. Twenty nine different genotypes were clearly discriminated. Differences were not found among the amplification profiles
from different individuals of the same cultivar. All the genotypes could be identified by the combination of three primers:
OPR-1, OPK-14 and OPA-1, seven genotype-specific markers being detected. Genetic relationships were estimated by the unweighted
pair-group method with arithmetic averaging (UPGMA). The genetic analysis of the results showed a gradual distance between
the various cultivars, making it difficult to identify well-differentiated phylogenetic groups, although two clusters were
distinguishable with 35 % similarity, in addition to three independent branches with lower similarity: Galega, Tentilheira
and Redondal. The dendrogram reflect some relationships for most of the cultivars according to the use of the fruit and ecological
adaptation. 相似文献
9.
Modelling the dynamics of the electron transport rate measured by PAM fluorimetry during Rapid Light Curve experiments 总被引:1,自引:0,他引:1
We propose a dynamic model specifically designed to simulate changes in the photosynthetic electron transport rate, which
is calculated from fluorescence measurements when plants are exposed, for a short time, to a series of increasing photon flux
densities. This model simulates the dynamics of the effective yield of photochemical energy conversion from the maximum and
natural chlorophyll fluorescence yields, taking into account a cumulative effect of successive irradiations on photosystems.
To estimate a characteristic time of this effect on photosystems, two series of experiments were performed on two benthic
diatom culture concentrations. For each concentration, two different series of irradiations were applied. Simplified formulations
of the model were established based on the observed fluorescence curves. The simplified versions of the model streamlined
the parameters estimation procedure. For the most simplified version of the model (only 4 parameters) the order of magnitude
of the characteristic time of the residual effect of irradiation was about 38 s (within a confidence interval between 20 and
252 s). The model and an appropriate calibration procedure may be used to assess the physiological condition of plants experiencing
short time-scale irradiance changes in experimental or field conditions. 相似文献
10.
Hybrids including Hystrix patula, H. duthiei and H. longearistata were obtained and genetic relationships among them were studied. Meiotic pairing in hybrids of H. duthiei × Psathyrostachys juncea (Ns), H. longearistata × Psa. juncea (Ns), Leymus multicaulis (NsXm) × H. duthiei, L. multicaulis (NsXm) × H. longearistata, Elymus sibiricus (StH) × H. patula, Roegneria ciliaris (StY) × H. patula, R. ciliaris (StY) × H. duthiei and R. ciliaris (StY) × H. longearistata averaged 5.76, 5.44, 11.94, 10.88, 10.08, 3.57, 0.46 and 0.90 bivalents per cell, respectively. The results indicated that
H. duthiei and H. longearistata had the NsXm genomes of Leymus, while H. patula contained the StH genomes and had a low genome affinity with the StY genomes of Roegneria. Results of genome-specific RAPD assay were comparable with the chromosome pairing data. According to the genomic system
of classification in Triticeae, H. patula should be considered as Elymus hystrix L., while H. duthiei and H. longearistata as Leymus duthiei and Leymus duthiei ssp. longearistata, respectively. 相似文献
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One of the least understood enzymatic steps in chlorophyll biosynthesis is the formation of isocyclic ring, which is catalyzed
by the Mg-protoporphyrin IX monomethyl ester (MgPME) cyclase that is involved in the conversion of MgPME to protochlorophyllide.
Several genes encoding part of this enzyme have been identified and functional analysis of them has been performed. The enzyme
plays important roles in higher plants and photosynthetic bacteria. The review focuses on the current knowledge of MgPME cyclase
coding genes, with emphasis on their organization, expression pattern, and functional analysis obtained from mutants. 相似文献
13.
The chlorophyll fluorescence (F) temperature curves in a linear time-temperature heating/cooling regime were used to study
heat-induced irreversible F changes in primary green leaves of spring barley (Hordeum vulgare L. cv. Akcent). The leaf segments were heated in a stirred water bath at heating rates of 0.0083, 0.0166, 0.0333, and 0.0500
°C s−1 from room temperature up to maximal temperature T
m and then linearly cooled to 35 °C at the same rate. The F intensity was measured by a pulse-modulated technique. The results
support the existence of the two critical temperatures of irreversible F changes postulated earlier, at 45–48 and 53–55 °C.
The critical temperatures are slightly dependent on the heating rate. Two types of parameters were used to characterize the
irreversibility of the F changes: the coefficient of irreversibility μ defined as the ratio of F intensity at 35 °C at the
starting/ending parts of the cycle and the slopes of tangents of linear parts of the F temperature curve. The dependence of
μ on T
m revealed a maximum, which moved from 54 to 61 °C with the increasing heating/cooling rate v from 0.0083 to 0.0500 °C s−1, showing two basic phases of the irreversible changes. The Arrhenius and Eyring approaches were applied to calculate the
activation energies of the initial increase in μ. The values varied between 30 and 50 kJ mol−1 and decreased slightly with the increasing heating rate. 相似文献
14.
C. -W. Zhu J. -G. Zhu G. Liu Q. Zeng Z. -B. Xie J. Pang Z. -Z. Feng H. -Y. Tang L. Wang 《Photosynthetica》2008,46(2):318-320
Net photosynthetic rate (P
N) of ear and flag leaf during grain filling stage and grain yield of plants with non-darkened or darkened flag leaf or darkened
ear were examined in two different CO2 concentrations: ambient (AC) and AC+200 μmol mol−1 (EC). Ear showed much higher enhancement (56 %) of P
N than flag leaf (23 %) under EC. Moreover, CO2 enrichment shortened the photosynthetic duration of flag leaf relative to ear. In this way the ratio of ear to flag leaf
contribution to grain yield increased from 1.18 (AC) to 1.39 (EC). 相似文献
15.
In this study, Dendrobium Sonia 17 plantlets were used to induce in vitro flowering. Inflorescences were induced and rooting was inhibited in the half-strength Murashige and Skoog medium containing
20 μM N
6-benzyladenine (BA). The medium with high P and low N contents was effective to induce inflorescences while the medium with
low P and high N contents was only effective to promote forming of shoots. In addition, the induced in vitro inflorescences were able to multiply and maintain without exhibiting a distinctive vegetative phase. Different morphologies
of in vitro flowers such as incomplete flower structures, abnormal and unresupinated in vitro flowers were observed. 相似文献
16.
Ethylene production and growth of callus cultures of lavandin (Lavandula offidnalis Cham x Lavandula latifolia Villars) cv.
Grosso were examined. Callus lines, derived from various kinds of primary expiants (shoot tip, leaf and calyx), exhibited
differences in ethylene production patterns independent of callus growth. Moreover these differences could not be ascribed
to the expiant source. Within a line, ethylene pattern paralleled callus growth curve. Variations in ethylene evolution were
induced in shoot tip callus by means of ACC, AVG and varied amounts of 2,4-D in the culture medium. Following all these treatments
callus growth was not altered. Hie decrease in 2,4-D concentration caused changes in Chl a and water content of the tissues. 相似文献
17.
The effect of ethylenediurea (EDU) was tested using the chlorophyll (Chl) a fluorescence transient analysis, performed with JIP-test, to assess ambient ozone (O3) effects on photosynthesis of adult trees under natural conditions. Twelve adult European ash (Fraxinus excelsior L.) trees, known to be sensitive or tolerant to O3, determined by presence symptomatic (S) or absence asymptomatic (AS) trees of foliar symptoms in previous years, were treated
either with distilled water containing 450 g m−3 EDU or with distilled water. Once a month across the growing season [the accumulated exposure over a threshold of 40 nmol(O3) mol−1 was 32.49 μmol mol−1 h−1], Chl a fluorescence transients were measured in vivo on dark-adapted leaves of 1-year-old labeled shoots, from the lower crown part. Twenty-five parameters were calculated. The
maximum quantum yield of primary photochemistry (ϕPo or Fv/Fm) did not differentiate between S-and AS-trees, while increased Chl content and de-excitation rates suggested compensation
of O3 injury in S-trees. Seasonal reductions in absorbing fluxes and increase in heat and fluorescence dissipation processes was
due to leaf ageing and drought, the latter suggesting water deficit influenced Chl a fluorescence stronger than ambient O3 exposure. AS-trees showed elevated probability of connectivity among photosystem 2 units, a mechanism to stimulate energy
dissipation and reduce photo-oxidative injury. EDU prevented the inactivation of reaction centers. This slight effect does
not warrant EDU as a tool to assess O3 effects on photosynthesis, while the JIP-test is suggested for a quantitative assessment in adult trees. 相似文献
18.
The pattern of the activity of arginine decarboxylase (ADC) and omithine decarboxylase (ODC) involved in polyamine synthesis
in ripening wheat seeds was examined. The aim was to study the polyamines and the activity of the two enzymes in correlation
with the growth processes occurring in the developing wheat seeds. The results obtained showed a very different pattern of
polyamine content in the two organs of caryopsis, and that the two enzymes in the embryos have a higher activity than in the
endosperms. Moreover, while in the embryos the ADC exhibits higher activity than the ODC, in the endosperms the activity of
ODC is about similar to that of ADC. This pattern is discussed in relation to the different histological characteristics of
embryo and endosperm tissues during seed development. 相似文献
19.
To examine the hypothesis that stomatal behavior of plants in dry soil is influenced by a slow recovery from daytime water
deficit, we studied the effect of repeated wetting of leaves during evening and night in Cryptomeria japonica seedlings grown in dry soil. After 7 and 10 days of leaf wetting treatment the midday leaf water potential decreased and
the transpiration rate increased, respectively. Therefore, we suggest that rapid recovery from daytime water deficit could
weaken the water conserving stomatal behavior that adapts to drought conditions in the roots. 相似文献
20.
We investigated the carbon isotope ratios and the diurnal pattern of malate accumulation in leaves and aerial roots of eight
species of Phalaenopsis grown in greenhouses. The leaves of all the species showed carbon isotope ratios and the diurnal patterns of malate content
typical of CAM plants. However, the aerial roots exhibited a large variation in the diurnal pattern of malate content among
species and even among plants within the same species, although carbon isotope ratios were always CAM-like values. Some aerial
roots showed the typical diurnal pattern of CAM, but others maintained high or low malate contents during a day without fluctuation.
In order to characterize more strictly the nature of the malate variation in the aerial roots, we further investigated a possible
variation of the diurnal pattern of malate among different aerial roots within an individual for Phalaenopsis amabilis and P. cornu-cervi. The diurnal pattern of malate content was varied even among different aerial roots within the same plant. Thus the photosynthetic
carbon metabolism in aerial roots of orchids is fairly complex. 相似文献