1,721,193 research outputs found
Somatic embryo, adventitious root and shoot regeneration in in vitro grown quince leaves as influenced by treatments of different length with growth regulators.
No full textThe purpose of this work was to acquire more information on the capacity of in vitro grown quince (Cydonia oblonga Mill.) leaves to simultaneously regenerate somatic embryos, adventitious roots and shoots, and to evaluate the variations induced on regeneration response by treatments of different length with growth regulators. After 2 days of liquid treatment with 2,4-dichlorophenoxyacetic acid, the leaves were cultured for 0, 3, 6, 9, 12, 15, 18 and 21 days on gelled growth medium containing the basal components of Murashige and Skoog and kinetin (Kin) 4.5 μM + naphthaleneacetic acid (NAA) 0.5 μM. At the end of each treatment period, the leaves were cultured on a transfer medium in the absence or in the presence of a growth regulator combination represented by N6-benzylaminopurine (BA) 2.66 μM + gibberellic acid 0.58 μM + indole-3-butyric acid 0.3 μM. The culture period for all the treatments was fixed to 52 days. Simultaneous regeneration response of somatic embryos, adventitious roots and shoots differed according to the length of the kinetin + naphthaleneacetic acid treatment and to the absence or the presence of growth regulators in the transfer medium. In the absence of growth regulators, only somatic embryos and roots were regenerated; the number of somatic embryos increased from the 0 day to the 6-9th day of treatment with kinetin + naphthaleneacetic acid, while root regeneration showed the opposite trend. After the 9th day, the production of somatic embryos decreased up to the 15th day and then stabilized, while roots showed only very small reduction up to the end of the experiment. In the presence of growth regulators in the transfer medium, adventitious shoots were regenerated together with somatic embryos and roots. The highest number of shoots was observed when the leaves were directly transferred from 2,4-dichlorophenoxyacetic acid treatments to growth regulator medium. Increasing the length of kinetin + naphthaleneacetic acid treatment, shoot regeneration decreased and by the 12th day no more shoots were produced. Somatic embryo regeneration peaked on the 6th day of culture with kinetin + naphthaleneacetic acid and showed the same trend as in the absence of growth regulators in the transfer medium, while root formation tended to increase with prolonging the kinetin + naphthaleneacetic acid treatment
Effect of high and low temperature on the leaf regenerating capacity of quince BA29 rootstock
No full textIn vitro grown quince (Cydonia oblonga Mill) BA 29 leaves were cultured for 2 days in liquid MS medium containing 2,4-D (11.3 μM). The subsequent gelled MS medium contained Kinetin (4.7 μM) and NAA (0.5 μM). The effects of three induction temperatures (23, 28, 33 ̊C) during 2,4-D induction treatment and six temperatures (19, 21, 23, 25, 28, 33 ̊C) during morphogenic structures development were evaluated. Moreover the effects of different shocks with low (0, -5, -10, -15 ̊C) or high temperatures (35, 40, 45, 50 and 60 ̊C) applied for different time (1, 2, 4, 6, 8, 24 hours) during the induction stage were compared. Percentage of regenerating leaves and number of somatic embryos and adventitious roots was recorded.
The different temperatures influenced both somatic embryo and root formation. In both the induction and development stage, 23 ̊C proved to be the best temperature for embryo production, while 21 ̊C applied during the development period appeared to be better for root formation. The short induction temperature treatments (1 hour) further enhanced embryo and root formation. Among the low temperatures, -10 ̊C was the most successful for both morphogenic processes, while among high temperatures the greatest number of morphogenic formations was observed at 40; in the latter conditions morphogenesis was higher than with low temperature. The most satisfactory treatment length for the 40 ̊C short temperature treatment was 1-4 hours for somatic embryo formation and 1-2 hour for adventitious root production.
These results suggested that a short shock at 40 ̊C, applied during induction performed at 23 ̊C, in combination with 21-23 ̊C during the development stage, is the best temperature combination for in vitro quince somatic embryogenesis
Morpho-physiological approaches to investigate lime-induced chlorosis in deciduous fruit trees species
No full textSeveral deciduous fruit tree species are affected by iron chlorosis when grown in calcareous soils and worldwide research on rootstock breeding and screening in relation to iron deficiency is carried out. For many years the goal of our department has been to investigate morphological and physiological aspects related to lime‐induced chlorosis, and to identify markers usable as tools for tolerance screening of clonal rootstocks. Experimental strategies using pot, hydroponic and in vitro culture have been used to understand if they are able to originate suitable indicators on developmental and biochemical changes resulting from iron deficiency. Results risen up from in vitro trials suggest that iron deficiency sensitive system should work in a divergent way from that of bicarbonate system. Physiological and morphological data highlight diverse syndromes and behaviors among the genotypes, probably reflecting properly perception, regulation, and activation of biological answer system to iron deficiency and bicarbonate. Recently, quince (Cydonia oblonga Mill.) minus‐ and plus‐variants have been obtained by in vitro somaclonal variation to clarify the agonistic relationship between bicarbonate and iron deficiency sensitive systems, that in turn can induce the activation of two specific gene expression pathways
Regeneration of somatic embryos and roots from quince leaves cultured on media with different macroelement composition
No full textThe effects of different macroelement combinations on somatic embryogenesis of quince (Cydonia oblonga Mill.) were tested. Leaves were excised from shoot cultures of quince clones and cultured on macroelement combinations of 8 different growth media. Callus production varied depending on the medium and the clone combinations. The influence of genotype and macronutrient combination on somatic embryo and root regeneration was also observed. Clone BA 29 showed the highest embryogenic properties and Murashige and Skoog-based medium appeared to be the most favourable for somatic embryo formation. Root regeneration was higher on Woody Plant Medium and Schenck and Hildebrandt-based media. Interactive effects between genotypes and macroelement combinations were also detected both for embryo and root formation. In all treatments, somatic embryos underwent early developmental arrest and failed to convert into plants. Differences in embryo and root regeneration observed among macroelement combinations may be ascribable to different levels of medium nitrogen and probably to the ratio between nitrate and ammonium
Different Responses Induced by Bicarbonate and Iron Deficiency on Microshoots of Quince and Pear
No full textEffect of 2,4-D and light quality on callus production and differentiation from in vitro cultured quince leaves
No full textThe effects of 2,4-dichlorophenoxyacetic acid (2,4-D) concentration, length of induction period and light quality on leaf regeneration of quince clone BA 29 were investigated. After 2, 4 or 6 days of induction with 2.5 mg l-1 or 5.0 mg l-1 2,4-D, leaves were cultured under red, blue, red+blue, far-red+blue, white, far-red light or darkness conditions. Leaves thereby treated showed different responses, with respect to somatic embryogenesis, callus, rednodular structures or roots. Callus production increased with increasing 2,4-D concentration and induction period, although it was not influenced by light quality; the only exception was far-red+blue light, which reduced callusing response. This result suggested involvement of the blue-absorbing photoreceptor system in the callus formation processes. A high regeneration of red-nodular structures with a meristematic appearance was also observed; from some histological characterizations, we presumed they were adventitious buds that were arrested at an early developmental stage. Red-nodular structures increased with decreasing 2,4-D concentration and induction period. In the regeneration of such structures, the blue-absorbing photoreceptor system appeared to have a negative effect but only at a low photoequilibrium value. In contrast, light quality which activated phytochrome induced an increment in regeneration, but the response did not vary for photoequilibrium values ranging from 0.43 to 0.86. For root regeneration, phytochrome seemed to be the only photoreceptor involved
Validation of a multi-analyte LC-MS/MS method for screening and quantification of 87 psychoactive drugs and their metabolites in hair
No full textA multi-analyte method for the detection and quantification of 87 psychoactive drugs (antidepressants, antipsychotics, benzodiazepines, and z-drugs) in human hair has been developed and fully validated using the liquid chromatography-tandem mass spectrometry system. Due to the remarkable increase in requests of hair sample tests (such as for driver's license renewals, child custody, DFA cases, and postmortem toxicology), we focused on the development of a rapid sample preparation. About 20 mg of hair samples, previously washed and cut into snippets, was ultrasonicated with 700 μl of methanol. Samples were then directly analyzed using a 4000 QTRAP (AB SCIEX, Foster City, CA, USA) with an electrospray ionization (ESI) Turbo VTM Ion Source. The validation criteria parameters were satisfactory and in accordance with the international guidelines. All the compounds tested were successfully detected. One important aspect is the LODs in the low picogram per milligram concentration which may suggest a potential use of this method in cases of detection of single drug exposure. However, the LC-MS/MS method has been successfully applied for the analysis of postmortem case
Project of Thin Targets for the NUMEN Experiment
No full textAbstract
.
The goal of the NUMEN collaboration is
the measurement of
the cross sections
of
Double Charge Exchange reactions for several couple of ion projectile
-
target
, in order to provide
helpful data
to
study the nuclear matrix elements of the neutrino
-
le
ss
double β
-
decay. The need
of big statistics and high precision in the measurements require the use of high intensity beams
and very thin targets. This creates some problems to the design of the target frame and to the
dissipation of the heat generated by
the beam. The present paper reports
a possible
solution for
the cooling system and the production technique of
a tin target, together with the results of the
preliminary tests of heat dissipation
- …
