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21.
L. Montesclaros N. Nicol E. Ubalijoro C. Leclerc-Potvin L. Ganivet J.-F. Laliberté M. G. Fortin 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1997,94(6-7):941-946
We have investigated the interaction between two different potyviruses and resistant cultivars of Lactuca sativa. Turnip mosaic virus (TuMV) and lettuce mosaic virus (LMV) were used to inoculate several cultivars under different temperature
regimes to characterize the resistance reaction. Resistance conferred by the recessive mo locus against LMV infection did not provide immunity. Virus accumulated in plant tissues to different levels depending on
the genetic background of the cultivar, suggesting that several genes were involved in the resistance phenotype. Under temperature
regimes that enhanced the hypersensitive reaction, resistant cultivars produced necrotic reactions. In contrast, resistance
to TuMV infection conferred by the dominant Tu locus resulted in complete immunity in the plant. No virus accumulated in inoculated leaves nor was any necrotic reaction
observed. The resistance loci were characterized at the genetic level by mapping them relative to molecular markers. Only
weak linkages could be identified to mo, again supporting the hypothesis that several genes are involved. The Tu locus was mapped in two different crosses relative to several markers, the closest two linked at less than 1 cM. A high-resolution
genetic map of the Tu locus was constructed by screening 500 F2 individuals for recombinants around that locus.
Received: 4 June 1996/Accepted: 15 November 1996 相似文献
22.
Summary Over a period of several years, quality characteristics of plant products have been studied intensively. Next to variety,
climate and location, the types and amounts of fertilizers used appeared to exert strong influences on quality parameters.
In recent research it could be shown that especially N-, but also P-, K- and Mg-supply affected dry matter content and furthermore
starch, crude protein, amino acids, nitrate, sugars and citric acid in cauliflower, lettuce, potato, spinach and tomato. Altogether
the results showed that the influence of variations in nutrient supply on the quality of important compounds in usable plant
parts is relatively high, but that different plants react not similarly to increasing or decreasing amounts of nutrients.
These relations are of special importance when the qualitative and nutritive values of plant products are evaluated for consumption
and processing purposes. 相似文献
23.
I. Papadopoulos 《Plant and Soil》1987,97(2):171-177
Summary The response of lettuce (Lactuca sativa L.) to residual soil salinity as influenced by the ionic composition of two different saline waters (ECw=3.1 dS/m, referenced at 25°C) and rain water, was investigated in a greenhouse experiment with three successive plantings
of lettuce in the same soil. One of the saline waters was saturated with gypsum (SO4=35 mol (−)m−3) and the other contained SO4 at 15 mol (−)m−3 and Na and Cl at 18 and 14 mol (±)m−3, respectively (mixed water). All waters were applied with a 0.3 leaching fraction.
Soil water salinity and sodium adsorption ratio (SAR) increased in both cases using saline waters. The effect of mixed saline
water was higher and became more marked after each planting, resulting from higher contribution of Na and Cl to soil salinity.
With both saline waters, soil solution became saturated with gypsum.
At first planting, gypsum saturated and mixed waters produced fresh yield increases of 15 and 24%, respectively, relative
to rain water. At second planting, however, there was reduction in yield of 11 and 22%, respectively, relative to rain water;
at third planting yield reduced by 22 and 76% with gypsum saturated and mixed water, respectively. 相似文献
24.
从陕西省关中地区春季和秋季自然发病的109个莴苣病株上分离到3种不同的病毒。经寄主范围与症状反应、抗性测定、传播途径、血清学反应以及电镜观察等鉴定表明,侵染莴苣的3种病毒是莴苣花叶病毒(LMV)、黄瓜花叶病毒(CMV)及蒲公英黄色花叶病毒(D YMV),其中DYMV在我国是首次报道。 相似文献
25.
Strong externally applied electrical field pulses are known to stimulate delayed luminescence from preilluminated blebs (hypotonically swollen vesicles originating from thylakoid membranes of broken chloroplasts) by up to 3 orders of magnitude. This phenomenon is known as electrophotoluminescence. Previous analysis showed the kinetics of the electrophotoluminescence to be biphasic, displaying a rapid (R) phase which decays towards a slower one (S) (Ellenson, J.L. and Sauer, K. (1976) Photochem. Photobiol. 23, 113–123). We demonstrate that these two components represent different processes. At low pH, a good kinetic separation is obtained between the two phases, which become distinct, with the S phase manifesting also an initial rise period. Under these conditions, it is possible to estimate separately the approximate rise times of the two phases. It is shown that the R and S components have a different dependence on the pH and on the time between the actinic flash and onset of the field. The field dependence is also different, with the S phase requiring a lower threshold field than R. From these observations, it is concluded that the R and S luminescence components are formed by different precursors. The difference in behaviour of the two phases during formation of the bleb indicates that the precursors of the R and S phases belong to different parts of the bleb. We suggest that R precursors are located in the wall of the swollen thylakoid and S precursors in the membrane formations which are attached to this wall. 相似文献
26.
Marie-José Delrieu 《BBA》1984,767(2):304-313
Treatments such as trypsinization (50 μg/ml per mg Chl for 1 h), osmotic shock of the chloroplasts or mild heating altered the oxygen evolution in such a way that the properties of the Photosystem II were simplified. After these treatments, the damping of the oscillation pattern of O2 yields induced by a flash series remained the same, irrespective of the level of inhibition induced by the treatment. This damping did not decrease with increasing flash energy, as observed in untreated chloroplasts. The light saturation curve of the S2 → S3 transition of the O2 evolving system no more exhibited the slow-increasing phase at high flash energy observed under normal conditions. The kinetic properties of the O2-evolving system were also simplified. After the treatments cited above, deactivation of S2 and S3 were identical and accelerated with respect to untreated chloroplasts. Turnover kinetics of the transitions S1 → S2 and S2 → S3 were also similar and simpler without a lag for S2 → S3. These results indicate that the treatments mentioned above disconnect one donor from the O2-evolving complex. This donor, under normal conditions, contributes to the increase of the quantum yield of the transition S2 → S3 at high flash energy. This donor is here denoted by D. Our results are in agreement with the following working hypothesis: the large miss, observed on the S2 → S3 transition without any contribution of the donor D, may be due to the fact that the system needs a conformation change of the O2-evolving complex in the S2 state, so that the main donor Y can oxidize the second H2O molecule in the water-splitting complex. In the inactive state corresponding to the absence of a conformation change, the donor D, being different in configuration, is likely to oxidize the S2 state into an S3 state at high light intensity. 相似文献
27.
J. Rouchaud C. Moons J. A. Meyer F. Benoit N. Ceustermans F. Van Linden 《Plant and Soil》1984,80(1):139-141
Summary Different growing conditions of early lettuces were assayed. Some plots of lettuces were grown covered with a perforated plastic sheet, and other plots were not covered. The soil of some plots was fertilized with a usual N+P+K+S fertilizer used at a normal rate, and the soil of other plots with a fertilizer containing only nitrogen at a rate about 40 times lower than the normal one for N. The total carotenes (provitamin A) contents of the ripe lettuces were measured. Covering with a plastic sheet always decreased the total carotenes contents. The N+P+K+S fertilizer used at normal rate increased, relatively to the nitrogen fertilizer lacking of P+K+S and used at low rate, the total carotenes contents of the non-covered lettuces, but had no or low effect on the total carotenes contents of the covered lettuces. 相似文献
28.
Mirafiori lettuce virus (MiLV), a plant RNA virus belonging to the genus Ophiovirus, is considered to be a causal agent of lettuce big-vein disease. In this study, inverted repeats of a fragment of the coat
protein (CP) gene of MiLV in a binary vector pBI121 were transferred via Agrobacterium tumefaciens-mediated transformation into lettuce (Lactuca sativa L.) in order to generate MiLV-resistant lettuce. Forty T1 lines were analyzed for resistance to MiLV by detecting MiLV in leaves, and two lines (lines 408 and 495) were selected as
resistant to MiLV. Both lines were susceptible to Lettuce big-vein associated virus (LBVaV), and line 495 showed higher resistance to MiLV than line 408. Further analysis indicated that line 495 showed resistance
to big-vein symptoms expression. Small interfering RNA (siRNA) molecules derived from the transgene were detected in plants
of line 495. MiLV was detected in roots but not in leaves of line 495 plants after MiLV inoculation, suggesting that resistance
to MiLV is less effective in roots than in leaves. 相似文献
29.
The results of the first detailed screening of a resistance to Bremia lactucae in naturally growing populations of Lactuca saligna are presented here. In total, 146 accessions from 25 populations of L. saligna originating in Israel (N = 136), France (N = 8), Jordan (N = 1) and Turkey (N = 1) were tested at seedling stage for their resistance to 10 highly virulent isolates (races) of B. lactucae from Lactuca sativa (DEG2, Bl:5, Bl:15, Bl:16, Bl:17, Bl:18, Bl:21, Bl:22, Bl:24 and Bl:25). Our study strongly supports the suggestion that L. saligna is indeed generally highly resistant to B. lactucae. However, our results provide evidence that at least at a seedling stage L. saligna may not be a non‐host plant for B. lactucae, as was hypothesised for approximately the last 30 years. Some accessions expressed a differential (i.e. race‐specific) response, which accords with other recently published data for this Lactuca species. Furthermore, some geographical differences in race‐specific resistance were observed, too. Tests performed at an adult‐plant stage, however, did not prove race‐specificity of the respective accessions. To summarise, what is behind the race‐specific character of the responses observed at a seedling stage is still uncertain, as is its comparability with the race‐specific resistance of some other Lactuca species such as L. sativa or L. serriola. The presence of plant stage‐dependent resistance, governed by a combined effect of different quantitative trait loci in young and adult plants of L. saligna, is discussed. 相似文献
30.
Chang-Hsien Yang Bernie Carroll Steve Scofield Jonathan Jones Richard Michelmore 《Molecular & general genetics : MGG》1993,241(3-4):389-398
The maize transposable element, Activator (Ac), is being used to develop a transposon mutagenesis system in lettuce, Lactuca sativa. In this paper, we describe somatic and germinal transactivation of Ds by chimeric transposase genes in whole plants. Constructs containing either the Ds element or the Ac transposase open reading frame (ORF) were introduced into lettue. The Ds element was located between either the 35S or the Nos promoter and a chimeric spectinomycin resistance gene (which included a transit peptide), preventing expression of spectinomycin resistance. The genomic coding region of the Ac transposase was expressed from the 35S promoter. Crosses were made between 104 independent R1 plants containing Ds and three independent R1 plants expressing transposase. The excision of Ds in F1 progenies was monitored using a phenotypic assay on spectinomycin-containing medium. Green sectors in one-third of the F1 families indicated transactivation of Ds by the transposase at different developmental stages and at different frequencies in lettuce plants. Excision was confirmed using PCR and by Southern analysis. The lack of green sectors in the majority of F1 families suggests that the majority of T-DNA insertion sites are not conducive to excision. In subsequent experiments, the F1 plants containing both Ds and the transposase were grown to maturity and the F2 seeds screened on medium containing spectinomycin. Somatic excision was again observed in several F2 progeny; however, evidence for germinal excision was observed in only one F2 family. 相似文献