Search results for "Propagation"

Axillary shoot proliferation in cultures of explants from mature Juniperus oxycedrus trees.

1995

We developed procedures for the micropropagation of Juniperus oxycedrus L. using shoot apices or nodal segments from mature plants. Of the media and explants examined, best culture establishment was obtained with shoot apices cultured on modified Schenk and Hildebrandt medium (SH medium) without growth regulators; however, shoot multiplication was only achieved when shoot apices isolated from shoots grown on SH medium without growth regulators were subcultured on SH medium containing 0.5 micro M benzyladenine. None of the auxins and methods tested for root induction provided satisfactory results.

Improved micropropagation in Polygala myrtifolia

2004

Stem segments from apical shoot tips of Polygala myrtifolia were used as primary explants to establish in vitro cultures. Axillary shoots produced on noncontaminated explants were excised and recultured in the same medium to increase the stock of shoot cultures. Equal molar concentrations of five cytokinins 2-isopentenyladenine (2iP), kinetin, zeatin, N6-benzyladenine (BA) and adenine were tested for ability to induce axillary shoot development from double node stem segments. The highest rate of axillary shoot proliferation was induced on Murashige and Skoog agar medium supplemented with 1.8 M BA. Seven indole-3-acetic acid (IAA) concentrations (2.8, 5.7, 8.6, 11.4, 14.3, 17.1 M) were t…

1972

The determination of reactivity ratios is simplified by using an excess of one monomer (M1) at a time large enough that the copolymers will have a very small content of the other monomer (M2). In this case chain propagation takes place almost exclusively by addition to polymer radicals with a terminal M1-unit (P) and monomer consumption by propagation of P may be neglected. One reactivity ratio (r1) is obtained from monomer conversions by means of a simple integrated equation which is valid up to high conversions. A calculation is proposed in order to account for the neglected propagation via P. The other reactivity ratio (r2) is obtained from copolymerizations with excess M2. As the new me…

STUDY ON CONVERSION OF ENCAPSULATED VITRO-DERIVED PROPAGULES OF 'C35' CITRANGE [C. SINENSIS (L.) OSB. × P. TRIFOLIATE (L.) RAF.]

2015

Fight against Citrus tristeza virus (CTV) implies the use of CTV-resistant rootstocks, such as citranges [C. Sinensis (L.) Osb. × P. Trifoliata (L.) Raf.]. The 'C35' represents a promising tolerant to CTV genotype. The employment of innovative in vitro techniques, such as encapsulation, could open new perspectives for this genotype propagation, particularly in the nursery activity. Preliminary experiments on calcium-alginate encapsulation of microcuttings (unipolar propagules) have already been performed to evaluate the use of tissue culture for the propagation and the preservation of different citrange rootstocks: Carrizo and Troyer. In the present study, the influence of different types a…

Kinetik der anionischen Polymerisation von Styrol in Dioxan mit Polystyryl-Natrium als Reaktionträger

1971

Die Wachstumskonstante des Polystyryl-Natriums bei der Polymerisation von Styrol in Dioxan wird als Funktion der Konzentration der „lebenden” Enden und der Temperatur gemessen und mit den entsprechenden Werten in anderen Losungsmitteln verglichen. Es zeigt sich, das die Polymerisation in Dioxan ausschlieslich uber das Kontaktionenpaar verlauft. The propagation rate constants of the anionic polymerization of styrene in dioxane were measured as a function of the “living” end concentration and of the temperature. They were compared with corresponding values in other solvents. It is shown that only contact ion-pairs are involved in this polymerization.

1973

The mechanism of radiation-induced polymerizations in the solid state has been a subject mostly open to speculation. As radiation usually generates several kinds of active species (radicals and ions) it is difficult to find out, which of these actually causes polymerization. We have developped a method distinguishing between cationic and anionic active centers. Cationic polymerizations are terminated by addition of a base such as sodium alkoxide in a suitable solvent. The alkoxide is incorporated into the polymer as an endgroup. This endgroup is determined analytically after isolation and purification of the polymer. The incorporation of alkoxy endgroups into the polymer is a proof of the o…

Efficient checking of coherence and propagation of imprecise probability assessments

2000

We consider the computational difficulties in the checking of coherence and propagation of imprecise probability assessments. We examine the linear structure of the random gain in betting criterion and we propose a general methodology which exploits suitable subsets of the set of values of the random gain. In this way the checking of coherence and propagation amount to examining linear systems with a reduced number of unknowns. We also illustrate an example.

Characterization and classification of different genotypes in a population of Cucumis melo based on their ability to regenerate shoots from leaf expl…

1995

Variability of the in vitro organogenic response from leaf explants of a seed population of Cueumis melo L. ev. Cantaloupe Charentais was analyzed to detect genotypic variability among individual seeds for shoot regeneration. Variation in shoot regeneration frequency among plants from different seeds was compared to that found among clonal replicas of each original plant. Clonal propagation was performed using in vitro culture of apical and axillary buds of axenic plants to avoid somaclonal variation. Results demonstrate the existence of highly significant differences among plants from the seed population. Regeneration frequency of leaf explants derived from clonally propagated sets of a si…

Long-Term Field Evaluation of Conventional vs. Micropropagated Plants of Chrysanthemum cinerariifolium

2022

Pyrethrum is a perennial herbaceous plant endemic to the eastern coast of the Adriatic Sea, and introduced in large areas of nearly all continents, where it is cultivated for the industrial extraction of pyrethrins. Pyrethrins are a group of six closely related monoterpene esters, widely used as natural insecticides. The world production of natural pyrethrins is lower than the market demand, and a wider introduction of this crop within the Mediterranean agrosystems could be an appealing opportunity for farmers and manufacturers. The availability of adequate amounts of selected plant material to bring into cultivation is, however, one of the major issues. Therefore, the in vitro propagation …

FLUMO: FLexible Underwater MOdem

2019

The last years have seen a growing interest in underwater acoustic communications because of its applications in marine research, oceanography, marine commercial operations, the offshore oil industry and defense. High-speed communication in the underwater acoustic channel has been challenging because of limited bandwidth, extended multipath, refractive properties of the medium, severe fading, rapid time variation and large Doppler shifts. In this paper, we show an implementation of a flexible Software-Defined Acoustic (SDA) underwater modem, where modulation parameters are completely tunable to optimize performance. In particular, we develop the system architecture following two key ideas. …