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1.
Conversion of d-[5-3H,6-14C]glucose to l-ascorbic acid in detached apices of Pelargonium crispum (L.) L'Hér cv Prince Rupert (lemon geranium) was accompanied by complete loss of tritium in the product. Chemical degradation of d-glucose which was recovered from the labeled apices yielded d-glyceric acid (corresponding to carbons 4, 5, and 6 of glucose) with a 3H:14C ratio of 4 to be compared with 9, the ratio in d-[5-3H,6-14C]glucose initially. Conversion of d-[6-3H,6-14C]glucose in the same tissue was accompanied by retention of tritium in l-ascorbic acid with a 3H:14C ratio comparable to that of compounds from the hexose pool. Results indicate that during l-ascorbic acid biosynthesis from glucose in Pelargonium crispum hydrogen at carbon 5 undergoes exchange with the medium, suggesting an epimerization at this carbon atom.  相似文献   

2.
《Journal of bryology》2013,35(4):691-694
Abstract

A new species Tristichella dimorpha is described and illustrated and a comparison made with the two other species in the genus, T. spiculifera and T. glabrescens, and with Clastobryella cuculligera to which it appears to be closely related, particularly in sporophytic characters.  相似文献   

3.
We found a potent platelet aggregation inhibitor in the culture broth of Streptomyces strain M-193. The inhibitor was purified as white crystals and investigated; it was identified as staurosporine. It strongly inhibited the platelet aggregation induced by collagen or ADP with IC50 values of 3.4 μm, and 11.6 μm, respectively. The inhibitor had no effect on thrombin-induced platelet aggregation or membrane stabilization against heat-induced hemolysis.  相似文献   

4.
In this study approximately 420 of the described species of Eucalyptus were examined for cyanogenesis. Our work has identified an additional 18 cyanogenic species, 12 from living tissues and a further six from herbarium samples. This brings the total of known cyanogenic species to 23, representing approximately 4% of the genus. The taxonomic distribution of the species within the genus is restricted to the subgenus Symphyomyrtus, with only two exceptions. Within Symphyomyrtus, the species are in three closely related sections. The cyanogenic glycoside was found to be predominantly prunasin (1) in the 11 species where this was examined. We conclude that cyanogenesis is plesiomorphic in Symphyomyrtus (i.e. a common basal trait) but has probably arisen independently in the other two subgenera, consistent with recent phylogenetic treatments of the genus. The results of this study have important implications for the selection of trees for plantations to support wildlife, and to preserve genetic diversity.  相似文献   

5.
Pelargonium × hortorum ‘Grand Prix’ which is susceptible to leaf yellowing and ‘Bergpalais’ which is not susceptible to leaf yellowing were chosen for the experiments. Ethylene production and action as well as the associated morphological response of Pelargonium shoots grown in the presence of a precursor of ethylene biosynthesis 1-aminocyclopropane-1-carboxylic acid (ACC), ethylene inhibitors: α-aminooxyacetic acid (AOA) and silver nitrate (AgNO3) and different cytokinins: (meta-topolin) (mT) or 6-benzylaminopurine (BAP) were studied. It was found that ‘Grand Prix’ was more sensitive to ethylene than ‘Bergpalais’ and it showed the leaf yellowing in response to 0.1 mg l?1 ACC. Moreover, it was noted that ACC added separately or together with cytokinin influenced Pelargonium morphogenesis. Depending on the concentration of ACC (0.1–2.0 mg l?1), it either stimulated or inhibited shoot and root formation as well as the growth of shoots and leaf blades. ACC-induced leaf yellowing in ‘Grand Prix’ was effectively inhibited by mT. In contrast, BAP did not enhance shoot quality. Simultaneously, the presence of mT in the medium resulted in up to a twofold increase in the ethylene production by ‘Grand Prix’ shoots throughout the culture period compared with the shoots growing on the BAP-medium. The inhibitor of ethylene action (AgNO3) added with cytokinin prevented the yellowing of Pelargonium shoots, but simultaneously influenced the formation of mature shoots with limited long-term multiplication potential. The shoots of P. × hortorum ‘Grand Prix’ treated with AgNO3 and mT emitted two- and sevenfold more ethylene after 11th and 21st day of culture compared with those treated with AgNO3 and BAP. It is suggested that mT inhibits the early senescence of Pelargonium in vitro by decreasing its sensitivity to ethylene.  相似文献   

6.
Essential oils from Erodium cicutarium were obtained by hydrodistillation (samples consisting of entire plants (ec1), leaves and stems (ec2)) and analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC/MS), resulting in a total of 177 components being identified. The essential oils were of a very similar chemical composition and consisted mainly of aliphatic compounds and their derivatives. Fatty acids and fatty acid derived compounds were the most common, 51.3% (ec1) and 60.1% (ec2), followed by carotenoid derived compounds, 12.6% (ec1) and 20.2% (ec2), and then terpenoids, 14.9% (ec1) and 14.2% (ec2). The main constituents in the oils were hexadecanoic acid, 22.8% (ec2) and 35.9% (ec1) and hexahydrofarnesyl acetone, 10.8% (ec2) and 11.6% (ec1). The results obtained differ markedly from those previously reported for the same species.  相似文献   

7.
In vitro clonal propagation of native Mediterranean Lavandula viridis was obtained from a mature field-grown plant. Single node explants were successfully established on Murashige and Skoog medium supplemented with 0.44 M of 6-benzyladenine. The highest multiplication rate (11.69 shoots/node) was obtained with 0.67 M 6-benzyladenine in Murashige and Skoog medium with macronutrients at half-strength. Shoots were easily rooted on Gresshoff and Doy medium. Increasing sucrose concentration from 58.4 to 87.6 mM resulted in a significant increase in rooting frequency. Eighty per cent of plantlets were successfully acclimatised to ex vitro conditions, exhibiting a normal development.  相似文献   

8.
Chemical fingerprinting of commercial Pelargonium capitatum (Geraniaceae) essential oil samples of south African origin was performed by GC, GC/MS, and (13) C- and (1) H-NMR. Thirty-seven compounds were identified, among which citronellol (32.71%) and geraniol (19.58%) were the most abundant. NMR Spectra of characteristic chemicals were provided. Broad-spectrum bioactivity properties of the oil were evaluated and compared with those of commercial Thymus vulgaris essential oil with the aim to obtain a functional profile in terms of efficacy and safety. P. capitatum essential oil provides a good performance as antimicrobial, with particular efficacy against Candida albicans strains. Antifungal activity performed against dermatophyte and phytopathogen strains revealed the latter as more sensitive, while antibacterial activity was not remarkable against both Gram-positive and Gram-negative bacteria. P. capitatum oil provided a lower antioxidant activity (IC(50) ) than that expressed by thyme essential oil, both in the 1,1-diphenyl-2-picrylhydrazyl (DPPH) and β-carotene bleaching tests. Results in photochemiluminescence (PCL) assay were negligible. To test the safety aspects of P. capitatum essential oil, mutagenic and toxicity properties were assayed by Ames test, with and without metabolic activation. Possible efficacy of P. capitatum essential oil as mutagenic protective agent against NaN(3) , 2-nitrofluorene, and 2-aminoanthracene was also assayed, providing interesting and significant antigenotoxic properties.  相似文献   

9.
《Journal of bryology》2013,35(3):535-541
Abstract

The distribution and variation in size of male gametophores associated with fertile, female cushions of Leucobryum glaucum and L. juniperoideum in two Welsh localities are described. Both dwarf and larger males were present in fruiting cushions of both species; no independent male plants were found. It is suggested that the scarcity of functional males might be a factor limiting sporophyte production in these species.  相似文献   

10.
This paper argues that our modern concept of biological heredity was first clearly introduced in a theoretical and practical setting by the generation of French physicians that were active between 1810 and 1830. It describes how from a traditional focus on hereditary transmission of disease, influential French medical men like Esquirol, Fodéré, Piorry, Lévy, moved towards considering heredity a central concept for the conception of the human bodily frame, and its set of physical and moral dispositions. The notion of heredity as a natural force, with a wide ranging capabilities of transmitting differentially both fundamental and accidental characters was generalized by that generation of physicians with the help of contemporary naturalists and physiologists. By 1830 the term hérédité was widespread, and it shared the explanatory and semantic qualities of traditional medical concepts like constitution and temperament. An analysis is given of the main developments that led to the conception of biological (including human) bodies as consisting of a layered, hierarchical organization of characters, differentially affected by the law of conservation (Heredity) and change (Inneity, Variation). The mid-century work of the French physician Prosper Lucas, Traité Philosophique et Physiologique de L' Hérédité Naturelle, is shown to be the culmination of the efforts of several generations of French physicians towards having a feasible, complexly structured notion of how heredity works.  相似文献   

11.
With a prerequisite of 5 hours in the light the detached leaves of wheat seedling and detached leaves and cotyledons of sunflower were able to utilize exogenous γ-aminobutyric acid, the amount of alanine and glutamine formed were increased. It was found that deamination of γ-aminobutyric acid was associated with γ-aminobutyric-pyruvate transaminase in the leaves of wheat seedling. The specific activity of this transaminase was enhanced about 5.6 fold by adsorption with calcium phosphate gel-Some properties of this transaminas were as follows: the optimum pH was 8.9. The produced amount of alanine was linear with time up to a period of one hour. The primary rate of reaction was proportional to enzyme concentration in the first hour. The relation of substrate concentration to the primary rate of alanine formation was determinated and Michaelis constant was evaluated about 2.6 × 10-3 M. The action of this transaminase in metabolism of γ-aminobutyrie acid was discussed.  相似文献   

12.
Journal of Plant Growth Regulation - Germination of rice (Oryza sativa L.) results in rapid accumulation of γ-aminobutyric acid (GABA), but its precise role in the process remains unclear. In...  相似文献   

13.
Changes in glucose-6-P, fructose-6-P, fructose-1,6-diP, 6-phospho-gluconate, phosphoenolpyruvate, 3-phosphoglycerate, and pyruvate levels in the leaves of the Crassulacean plant Kalanchoë daigremontiana Hammet et Perrier were measured enzymically during transitions from CO2-free air to air, air to CO2-free air, and throughout the course of acid accumulation in darkness. The data are discussed in terms of the involvement of phosphoenolpyruvate carboxylase in malic acid synthesis and in terms of the regulation of the commencement of malic acid synthesis and accumulation through the effects of CO2 on storage carbohydrate mobilization and its termination through the effects of malic acid on phosphoenolpyruvate carboxylase activity.  相似文献   

14.
15.
16.
Chang NK 《Plant physiology》1981,68(2):464-468
The enzymes necessary to assimilate ammonia either via glutamine synthetase and glutamate synthase or via the glutamate dehydrogenase pathways are present in both green and white leaf tissues of Kalanchoë fedtschenkoi. Nitrate reductase activity develops to a maximum in a Crassulacean acid metabolism (CAM) plant canopy before either ribulose 1,5-bisphosphate carboxylase, or phosphoenolpyruvate carboxylase, or CAM. Nitrate reductase also is activated each morning and is inactivated late in the day as in other plants. However, there does not appear to be any direct relationship between nitrate reductase activity and the level of acid, its daily pattern or the amplitude of CAM. Though nitrate reductase is activated maximally each day by light, in Kalanchoë leaves for six days the activity followed a precise daily pattern independent of continuous light or dark.  相似文献   

17.
The dynamics of the biomass, primary production, and P/B ratio of floating and attached forms of green filamentous alga Cladophora glomerata (L.) Kütz. was studied for the shallow water littoral area of the Neva Estuary in 2003–2006. The biomass of the floating algae constituted up to 70% of the total biomass, and the primary production reached up to 90% of the total for the depths of 0–1 m from the middle of July to the end of August.  相似文献   

18.
C Li  Y-M Zhang 《Heredity》2011,106(4):633-641
There are two main classes of multi-subunit seed storage proteins, glycinin (11S) and β-conglycinin (7S), which account for approximately 70% of the total protein in a typical soybean seed. The subunits of these two protein classes are encoded by a number of genes. The genomic organization of these genes follows a complex evolutionary history. This research was designed to describe the origin and maintenance of genes in each of these gene families by analyzing the synteny, phylogenies, selection pressure and duplications of the genes in each gene family. The ancestral glycinin gene initially experienced a tandem duplication event; then, the genome underwent two subsequent rounds of whole-genome duplication, thereby resulting in duplication of the glycinin genes, and finally a tandem duplication likely gave rise to the Gy1 and Gy2 genes. The β-conglycinin genes primarily originated through the more recent whole-genome duplication and several tandem duplications. Purifying selection has had a key role in the maintenance of genes in both gene families. In addition, positive selection in the glycinin genes and a large deletion in a β-conglycinin exon contribute to the diversity of the duplicate genes. In summary, our results suggest that the duplicated genes in both gene families prefer to retain similar function throughout evolution and therefore may contribute to phenotypic robustness.  相似文献   

19.
20.
Résumé Une femelle pondeuse de Poliste ne réagit pas e la même façon envers les deverses catégories d'ufs qu'elle rencontre sur le nid. Notamment, il arrive qu'elle détruise systématiquement tous ceux qui proviennent d'autres femelles (ufs étrangers), alors qu'elle respecte les siene propres. Cette différence de traitement selon l'origine de l'uf définit l'oophagie différentielle.On cherche à analyser, dans le présent article, divers facteurs, internes et externes, qui sont à l'origine de ce comportement.Dans la société polygyne, l'oophagie différentielle devient le privilège de l'individu . Cette spécialisation d'une seule Guêpe dans l'oophagie assure l'homogénéité du couvain: en règle, toute la descendance provient de la même mère.
Summary A laying female ofPolistes does not react in the same manner to the different categories of eggs which she encounters in the nest. Particularly, she may exterminate systematically all those layed by other females (foreign eggs) while she respects her own. This difference of treatment occording the origine of egg defines the differential oophagy.In that paper, various internal and external factors which may be the start of that behaviour, are analysed.In the polygynous society, the differential oophagy becomes the privilege of the subject . This specialization of a single wasp in the oophagy assure the homogeneity of the brood: as a general rule, all the progeny comes from the same mother.

Zusammenfassung Eine LegerinPolistes reagiert nicht auf die selbe Art bei den verschieden Kategorien die sie antrifft im Nest. Namentlich kommt es vor dass sie systematisch alle Eier vernichtet die sie von anderen Weibchen vorfindet (d. h. fremde Eier), während sie ihre Eigenen respektiert. Diese unterschiedliche Behandlung je nach herkommen des Eies bezeichnet mandifferentiale Oophagie In diesem Artikel versucht man die verschiedenen intern und extern Faktoren zu analysieren, sowie was das Benehmen ihres Ursprungs sind.Bei den Polygyne die differentiale Oophagie wird das Privilegium des Einzelwesens . Diese Spezialization einer einzelnen Wespe der Oophagie sichert die Gleichartigkeit der Brut: in der Regel stammen alle Nachkommen von der selben Mutter.


Ce travail a été fait en collaboration avec Ed. Ph.Deleurance.  相似文献   

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