Search results for "auxin"

Development of the adhesive pad on climbing fig (Ficus pumila) stems from clusters of adventitious roots

2003

Vines have different climbing strategies; one type, called clinging vines, has developed a specialized structure, the adhesive pad that secretes a sticky substance that adheres to almost any substrate. In this study on the climbing fig, Ficus pumila L., we report on the developmental anatomy of clusters of adventitious roots that become transformed into this unique structure. Clustered adventitious roots in F. pumila are initiated in pairs on either side of a vascular bundle at the 2nd to 3rd internodes of young stems. After emergence through the cortex and epidermis, root hairs form, which secrete a substance that stains positively for polysaccharide and protein. The adventitious roots and…

Grapevine fruit set: Physiology of the abscission zone

2000

Effects of ethylene and of 'anti-ethylene' compounds on the floral pedicel abscission zone in grapevines were analysed via a laboratory model consisting of isolated flowers held in Petri dishes. Our model permitted precise determination of abscission and enabled us to test a range of physiologically-active compounds including ethylene precursors, and antagonists of ethylene action. For example, a precursor of ethylene, 1-aminocyclopropane-l-carboxylic acid, had the same effect as ethylene in promoting abscission. Conversely, an inhibition of ethylene action by silver thiosulfate or an inhibition of ethylene synthesis by amino-oxyacetic acid both strongly inhibited abscission zone function. …

Hormone Effects on the Membrane Potential and on Sucrose-Induced Depolarization of Young <italic>Citrus</italic> Leaves

1992

Fatty acid composition of mutants of the moss Physcomitrella patens

1981

Abstract The fatty acid composition of various mutant strains of the moss Physcomitrella patens has been compared to the wild-type. These included strains defective in their responses to auxins and/or cytokinins, one which releases much more cytokinin into the medium than the wild-type, and two aphototropic strains. The lipids of the aphototropic mutants were also studied after culture in different light regimes. Although some differences in fatty acid composition have been found between strains, these alone are probably not responsible for their physiological differences. Considerable changes occur in many fatty acids in senescent or dark-grown material, including changes in the proportion…

Secondary somatic embryogenesis and plant regeneration in myrtle (Myrtus communis L.).

1998

Immature seeds, as well as hypocotyls and cotyledons excised from seedlings of Myrtus communis L., were cultured on media containing half-strength Murashige and Skoog macronutrients (MS/2) with combinations of auxins and cytokinins, in order to study their morphogenetic competence. Somatic embryogenesis was obtained from cotyledons, hypocotyls and 2-month-old immature seeds with 0.1 mg/l 2,4-dichlorophenoxyacetic acid (2,4-D). The percentage of explants showing this primary somatic embryogenesis ranged from 4% for hypocotyls to 12% for 2-month-old immature seeds. In the latter, somatic embryogenesis was also obtained in media containing 2,4-D plus a cytokinin, and with only a cytokinin. Som…

Potential use of new diphenylurea derivatives in micropropagation of Capparis spinosa L.

2011

A protocol for in vitro multiplication of caper (Capparis spinosa L. subsp. rupestris) from nodal segments collected from mature plants was developed. For shoot multiplication, one auxin (indol-3-butyric acid, IBA) and cytokinins of two different classes were used: the N6-substituted adenine derivatives 6-benzylamino purine (BAP), and the two synthetic phenylurea derivatives N-phenyl-N′-benzothiazol-6-ylurea (PBU) and N-phenyl-N′-(1,2,3-thidiazol-5-yl) urea (thidiazuron, TDZ). Maximum shoot production was achieved from explants cultured with the adeninic cytokinin BAP (4 μM) and the auxin IBA (0.5 μM). New shoots longer than 1 cm were used for rooting. To induce root formation, three auxins…

Effect of plant growth regulators and basal media onin vitro shoot proliferation and rooting ofMyrtus communis L.

1996

The influence of macronutrients and growth regulators on in vitro shoot proliferation and rooting of an East Spanish population ofMyrtus communis L. were studied. Preincubation of field material on a medium without mineral salts prevented the browning from phenolic exudates. For multiplication, nodal segments of 5 mm fromin vitro produced shoots were cultured on Murashige and Skoog (MS), Schenk and Hildebrandt (SH) and Heller (H) media (full strength or diluted to 1/2 or 1/4), with 6-benzylaminopurine (BAP) at concentrations 4.4, 13.3 and 22.2 ΜM or kinetin (K) at concentrations 4.7, 14.0 and 23.2 ΜM. The optimum shoot proliferation was on quarter-strength MS medium with 4.4 ΜM BAP, whereas…

Micropropagation of bay laurel (Daphne gnidiumL.)

1996

SummaryProcedures have been developed for the micropropagation of Daphne gnidium, a shrub species of ecological interest, using explants of juvenile and adult origin. Shoot proliferation rates were significantly affected by both salt formulation and benzylade- nine concentration. Best results were obtained on WP medium with 5 µM BA. The presence of indoleacetic acid in the induction medium improved BA-induced axillary bud proliferation from juvenile explants. Rooting of shoots produced in culture was difficult, especially those of adult origin. Besides an absolute requirement for auxin, calcium concentration and the pH of the medium affected the formation of adventitious roots from regenera…

Spermidine and morphogenesis in single cell cultures of Sideritis angustifolia lag.

1990

Abstract Single cells from hypocotyl-derived callus of Sideritis angustifolia were evaluated for morphogenesis when cultured in either solidifier or liquid Murashige and Skoog medium supplemented with various concentrations of spermidine, naphthaeneacetic acid (NAA), benzyladenine (BA) and dicyclohexylamine (DCHA). Spermidine (Spd) did not replace the hormonal requirements for cell division and callus formation, but affected growth induced by NAA or BA. This polyamine increased the plating efficiency of cells cultured in the presence of NAA (0.05, 0.54 and 5.40 μM) or BA (0.40, 4.40 and 8.80 μM). In contrast, Spd reduced growth induced by 10.80 μM NAA, optimal auxin concentration for callus…

Micropropagation of Metrosideros excelsa

2008

Multiple shoots were induced on stem segments of a 8-year-old plant of Metrosideros excelsa Sol ex Gaertn. ‘Parnel’. Axillary shoots produced on uncontaminated explants were excised, segmented and recultured in the same medium to increase the stock of shoot cultures. The Murashige and Skoog (MS) medium, augmented with different concentrations of 2- isopenthenyladenine (2iP) and indole-3-acetic acid (IAA), either singly or in combinations, as potential medium for shoot multiplication by nodal segments was tested. In the following experiment equal molar concentrations of four cytokinins [2iP, kinetin, zeatin and N6-benzyladenine (BA)] in combination with equal molar concentrations of three au…