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1.
The infectivity and development of four populations of Meloidogyne hapla were compared, at three temperatures, on tomato and two varieties of cucumber. A population from Canada produced few root-galls on cucumber and, except at 24 C, no larvae developed into adult females and produced egg masses. In contrast, a population with 45 chromosomes from America produced many galls on cucumber and small proportions of larvae became females and produced egg masses at 20 and 24 C. At 18 C this population produced no egg masses on cucumber, but a population from Britain and one from America with 17 chromosomes produced more egg masses at this temperature than at 20 or 24 C. Dissection of the galls showed that on cucumber many larvae died or their growth and development was slowed. 相似文献
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Aqueous extracts of smoke, derived from Themeda triandra, a fire-climax grass, and Passerina vulgaris, a fynbos plant, stimulated the growth of primary root sections of tomato roots in suspension culture. The optimal dilution for both extracts was 1:2000. Several of the fractions obtained from TLC separation of the Themeda and the Passerina extracts significantly promoted primary root growth. The auxins naphthaleneacetic acid (NAA), indolebutyric acid (IBA) and indoleacetic acid (IAA) were found to stimulate the growth of the primary root axis, with IAA and NAA significantly promoting lateral root number. Similarly, the naturally occurring cytokinins, zeatin and its derivatives (zeatin-O-glucoside; dihydrozeatin and zeatin riboside) stimulated primary root length. Zeatin and dihydrozeatin promoted secondary root growth, but only at very low concentrations. 相似文献
4.
C. EDUARDO VALLEJOS 《Plant, cell & environment》1991,14(1):105-112
Abstract. Comparisons were made between the changes in mRNA levels induced by low night temperatures in the cold–sensitive tomato and two altitudinal ecotypes of the wild species L. hirsutum. Changes in mRNA levels were detected by resolving in vitro translation products of poly(A)+ RNA by 2-D PAGE. The treatment was applied by first growing plants in a thermoperiod of 25/18°C and then switching to 25/6°C. All tomatoes displayed a diurnal cycling in which a set of mRNAs accumulated at the end of the 18°C nights, whereas another accumulated at the end of the 25°C days. The accumulation of night specific mRNAs was inhibited by 6°C nights in the cold sensitive tomatoes while that of the tolerant one was only marginally affected. All tomatoes showed a similar reduction in the apparent turnover rate of the day specific mRNAs during the 6°C nights. Finally, low night temperatures induced the accumulation of six to eight mRNAs in all genotypes. This number increased by 15 in L. esculentum after the seventh night and are likely involved in stress response rather than acclimation/tolerance. The tomato is proposed as a genetic model to discriminate genes involved in acclimation/tolerance from those involved in stress response. 相似文献
5.
Maarten Jongsma Maarten Koornneef Pim Zabel Jacques Hille 《Plant molecular biology》1987,8(5):383-394
Tomato protoplasts have been transformed with plasmid DNA's, containing a chimeric kanamycin resistance gene and putative tomato origins of replication. A calcium phosphate-DNA mediated transformation procedure was employed in combination with either polyethylene glycol or polyvinyl alcohol. There were no indications that the tomato DNA inserts conferred autonomous replication on the plasmids. Instead, Southern blot hybridization analysis of seven kanamycin resistant calli revealed the presence of at least one kanamycin resistance locus per transformant integrated in the tomato nuclear DNA. Generally one to three truncated plasmid copies were found integrated into the tomato nuclear DNA, often physically linked to each other. For one transformant we have been able to use the bacterial ampicillin resistance marker of the vector plasmid pUC9 to rescue a recombinant plasmid from the tomato genome. Analysis of the foreign sequences included in the rescued plasmid showed that integration had occurred in a non-repetitive DNA region. Calf-thymus DNA, used as a carrier in transformation procedure, was found to be covalently linked to plasmid DNA sequences in the genomic DNA of one transformant. A model is presented describing the fate of exogenously added DNA during the transformation of a plant cell. The results are discussed in reference to the possibility of isolating DNA sequences responsible for autonomous replication in tomato. 相似文献
6.
Decapitated tomato plants were supplied via the roots with [8-14C]-kinetin or [8-14C]-benzyladenine in a nutrient solution for a period of 24 h. After this time the root material, the root sap produced during the 24 h period and the nutrient solution remaining at the end of the experiments were analysed for cytokinins. HPLC techniques and chemical treatments were used to tentatively identify radioactive metabolites formed. Uptake of kinetin and benzyladenine by the roots was found to be limited but once within the root tissues metabolism was both rapid and extensive.At least 14 metabolites of kinetin were recovered from root tissue and root sap. Many of these appeared to be degradation products. There was, however, some evidence of formation of zeatin-like derivatives. Side-chain cleavage of the original kinetin which occurs rapidly is suggested as a possible route for the eventual production of these endogenous cytokinin forms.The benzyladenine taken up by the roots was apparently both ribosylated and glucosylated. No unmetabolized benzyladenine was detected in the root tissues after 24 h. Only very low levels of radioactivity were associated with the retention time of adenine, suggesting that in the case of benzyladenine side-chain cleavage is of limited importance.The significance of these reactions in relation to the potential use of cytokinins in the regulation of plant growth is discussed. 相似文献
7.
N. Marban-Mendoza A. Jeyaprakash H.-B. Jansson R. A. Damon Jr. B. M. Zuckerman 《Journal of nematology》1987,19(3):331-335
Significant control of tomato root knot was achieved by applications of the lectins Concanavalin A (Con A) and Limax flavus agglutinin in greenhouse, growth chamber, and microplot trials. Four consecutive weekly applications at lower concentrations of Con A yielded better control than single applications at a higher total concentration. The present state of knowledge on binding of Con A to soil nematodes and the in vitro effect of this lectin in chemotactic behavior are discussed. The mode of action of Con A on root-knot control is unknown. 相似文献
8.
P. A. Scolnik P. Hinton I. M. Greenblatt G. Giuliano M. R. Delanoy D. L. Spector D. Pollock 《Planta》1987,171(1):11-18
The tomato (Lycopersicon esculentum (L.) Mill.) ghost plant is a mutant of the San Marzano cultivar affected in carotenoid biosynthesis. ghost plants exhibit a variable pattern of pigment biosynthesis during development. Cotyledons are green but true leaves are white. Green sectors, which appear to be clonal in origin, are frequently observed in the white tissue. Because of the lack of photosynthesis ghost plants have a very low viability in soil. We have developed a strategy for propagating ghost plants that employs organ culture to generate variegated green-white plants which, supported by the photosynthetic green areas, develop in soil to almost wild-type size. These plants were used to analyze the pigment content of the different tissues observed during development and plastid ultrastructure. Cotyledons and green leaves contain both colored carotenoids and chlorophyll but only the colorless carotenoid phytoene accumulates in white leaves. the plastids in the white tissue of ghost leaves lack internal membrane structures but normal chloroplasts can be observed in the green areas. The chromoplasts of white fruits are also impaired in their ability to form thylakoid membranes. 相似文献
9.
F. Rollo A. La Marca A. Amici 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1987,73(4):501-505
Summary Twelve seed specimens of varying ages and from different archaeological sites were analyzed for the presence of polymerized DNA and RNA. Amongst the samples tested, one of Vitis vinifera from an archaeological site in Iran (2,000–3,000 B.C.) was found to be completely devoid of nucleic acids. Zea mais seeds of Precolumbial age from Peru (about 800 A.D.) contained depolymerized DNA and RNA. Samples of Vitis vinifera and Rubus sp. from a Lombard archaeological site (800 A.D.) as well as radiocarbon dated seeds from the site of the Spring Sanctuary near Metaponto (I–IV century B.C.) were found to contain polymerized DNA and rRNA bands. However the electrophoretic properties of the rRNAs in one case and hybridization experiments performed with cloned seed DNA in the other, clearly demonstrated that the polymerized nucleic acids were not of plant origin. 相似文献
10.
Photosensitivity of germination of white clover ( Trifolium repens L. cv. Podkowa) seeds was studied under water deficit (low water potential) conditions at 25°C. The seeds showed negative photoblastism, which was most pronounced at -0.03 MPa polyethylene glycol solution. Inhibition was observed at two different wavelength bands with maxima at 660 nm (R) and around 730 nm (FR). Red light acted identically to white light (maximum inhibition ca 50%). The effect of far-red illumination was less inhibitory (20–30%). The photoresponse required long illuminations (3 h exposures); saturation level was at 0.1 W m−2 , independently of the light quality. White clover seed germination showed no reversibility of the effects of R and FR light. Prolonged illumination with R and FR increased the inhibition, and intermittent illumination had a higher effect than a continuous one. It was concluded that the photoinhibition of germination of seeds of Trifolium repens involves a reaction dependent on the rate of phytochrome interconversion, a property that is characteristic for the high irradiance reaction. 相似文献