ABSTRACT: The antimicrobial activity of leaf and callus extracts of Melia azedarach was tested on in vitro shoot cultures of the peach rootstoch ‘MRS 2/5’ (Prunus cerasifera × Prunus spinosa) that were heavily contaminated with Sphingomonas paucimobilis (Sp) and Bacillus circulans (Bc). The extracts were filter-sterilised and added at 0%, 1%, 5%, 10% and 20% to a modified Murashige and Skoog proliferation
medium previously autoclave-sterilised. Up to about 17% shoots died with 10–20% extract, except for Sp-contaminated shoots,
whose survival was reduced to 50% after treatment with 20% extract. No shoots died with 1% to 5% supplement. The undiluted
leaf extract showed bactericidal activity on plated Sp and Bc isolates. The homogenates of shoots randomly collected from
treated cultures were processed for bacterial colony counting. Thus the 10% supplement was the best treatment for ridding
Bc-contaminated cultures of bacteria (although 5% had a similar bactericidal effect), and allowing shoot growth and proliferation
comparable to controls at the fifth subculture on a standard medium, while 20% extract was needed to eliminate Sp, and could
induce higher growth and proliferation rates in surviving shoots than in untreated cultures. Callus extract was ineffective.
The bactericidal activity of the leaf extract seemed attributable to a synergistic effect of azadirachtin with other unidentified
compounds present in the extract.
European Journal of Plant Pathology 04/2012; 123(2):195-205. · 1.41 Impact Factor
ABSTRACT: Use of lysozyme was tested for treatment of bacterial contaminations in in vitro shoot cultures of quince (Cydonia oblonga) ‘BA 29’ and the hybrid (Prunus persica × P. amygdalus) rootstock ‘GF 677’. Shoots which had been contaminated for about 1 yr by Bacillus circulans and Sphingomonas paucimobilis were treated in liquid culture, at pH 4.5, with 9–36 mg ml−1 egg white lysozyme (EWL), and compared to each other and to untreated cultures for their growth, proliferation, and number
of bacterial colony-forming units in the tissues. EWL did not negatively affect shoot growth up to 18 mg ml−1; furthermore, the proliferation rates of EWL-treated shoots were sometimes higher than those of controls. In contrast, the
concentration of 36 mg ml−1 had some deleterious effect on the regrowth capacity and shoot production of ‘GF 677’ at the first subculture to solid medium
after EWL, treatments. EWL had a simple bacteriostatic effect against Sphingomonas paucimobilis; in contrast, it was effective at 18 mg ml−1 in eliminating Bacillus circulans in both ‘BA 29’ and ‘GF 677’ cultures, after optimal treatment duration.
In Vitro Cellular & Developmental Biology - Plant 04/2012; 39(3):327-331. · 1.50 Impact Factor
ABSTRACT: The effect of different sealing materials [i.e., polyvinyl chloride (PVC) transparent film, and Parafilm (PARA) for Petri
dishes was investigated on shoot regeneration from quince (Cydonia oblonga L.) ‘BA 29’ leaf explants. Leaves were excised from proliferating shoot cultures, transversally scored, and placed with the
abaxial side down in 60-mm Petri dishes containing 10 ml of Murashige and Skoog modified medium, with 5.4 μM α-naphthaleneacetic acid, 4.5 μM thidiazuron, 200 mg l−1 cefotaxime, and 0.25% (w/v) Phytagel (IM medium) for shoot bud induction, and cultured in darkness at 22±2°C for 28 d. Then
the explants were transferred to standard conditions (16-h photoperiod at 30 μmol m−2 s−1 photosynthetically active radiation) on a medium similar to IM, except for lack of NAA, and with 0.65% (w/v) agar instead
of Phytagel, for an additional 15–28 d. The sealing combinations PARA-PARA, PARA-PVC, PVC-PARA, and PVC-PVC (in the induction-expression
phases) were compared during regeneration and for their carry-over effect on shoot development after transfer of explants
to an elongation medium (0.9 μM 6-benzyladenine). Carbon dioxide accumulated at 27.2 mmol mol−1 at the end of induction, and gradually decreased from 35.4 mmol mol−1 on day 9 to 22.5 mmol mol−1 on day 28 of the expression phase in PARA-sealed Petri dishes, being always much higher than after sealing with PVC (1–2
mmol mol−1). Ethylene concentration was 0.1 and 0.04 μmol mol−1 in the first part of the induction and expression phase, respectively, in PARA-sealed Petri dishes, and slightly decreased
with duration of exposure to light during expression; while it was absent in most PVC-sealed dishes. The PARA-PARA and PVC-PVC
(induction-expression) combinations gave, respectively, the worst and best results of regeneration and successive shoot development.
In Vitro Cellular & Developmental Biology - Plant 06/2004; 40(4):384-388. · 1.50 Impact Factor
ABSTRACT: Treatments differing from each other for the type of tube closure (i.e., cotton plug for free gas exchange, airtight rubber
cap, and rubber cap with ethysorb) and/or rooting culture medium (i.e., enriched or not by 25 to 100 µM acetylsalicylic acid) were compared for their effects on gaseous composition of the culture atmosphere and microcutting rooting
of the GF 677 (Prunus persica × Prunus amygdalus) hybrid. Rubber capping, which leads to rapid ethylene accumulation inside tubes, strongly reduced rooting time and in some
cases enhanced final rooting percentage over that of cotton plugs. Ethysorb almost completely absorbed ethylene produced by
shoots, which showed lower rooting percentages within 9 d than microcuttings cultured in the absence of ethysorb. In contrast,
no significant difference in rooting was found between the two treatments after 14 d. Carbon dioxide concentration was similar
in all treatments within 5 to 9 d and seemed to be ineffective for rooting. The influence of acetylsalicylic acid on rooting
was unclear. Root number and length were not significantly influenced by the treatments. These results demonstrate that the
use of airtight closures, leading to rapid ethylene accumulation, can reduce time of rooting expression for GF 677 microcuttings.
However, free gas exchange towards the end of the rooting period (from Day 9 to Day 14) is advisable to prevent leaf yellowing.
No significant difference in plantlet survival and growth after transfer ex vitro was found among treatments.
In Vitro Cellular & Developmental Biology - Plant 04/1997; 33(1):26-29. · 1.50 Impact Factor
ABSTRACT: Shoots of “San Castrese” and “Portici” apricots (Prunus armeniaca L.) free of cultivable bacteria, shoots of the same origin exhibiting bacterial contamination after repeated subcultures,
and contaminated shoots treated with cefotaxime were compared for gas exchange, proliferation rate, and fresh and dry weight.
Cultures of San Castrese contaminated byBacillus circulans andSphingomonas paucimobilis, and of Portici contaminated withStaphylococcus hominis andMicrococcus kristinae, including those treated with cefotaxime, showed comparable shoot weights and lower proliferation rates than healthy cultures.
Bacteria, even if not visible until the end of subculture, markedly influenced the gaseous composition of the jar headspace.
Healthy cultures clearly showed photosynthetic activity at 60 μM·m−2·s−1 photosynthetically active radiation; in contrast, oxygen quickly decreased and carbon dioxide increased in contaminated cultures,
including those treated with cefotaxime, in which bacteria became visible in the culture medium only after repeated subcultures.
In Vitro Cellular & Developmental Biology - Plant 12/1995; 32(1):51-56. · 1.50 Impact Factor
ABSTRACT: The influence of culture flask closures, i.e., cotton plugs and rubber and aluminum-foil caps, on headspace gas composition
and growth of leaf petiole callus-derived GF 677 cell suspensions was comparatively tested. Oxygen concentration always remained
comparable to that of the lab atmosphere and CO2 and C2H4 levels were slightly higher when flasks were closed with cotton plugs. By contrast, the gas environment markedly changed
within 72 to 96 h in culture inside rubber and aluminum-capped flasks. Under rubber caps, CO2 increased up to 18%, with a net production of about 0.8 mmol CO2, oxygen decreased to 6% within 72 h, and ethylene accumulated up to 9 µl liter−1 after 96 h. When aluminum foil closures were used, C2H4 and CO2 increased over the first 72 h, reaching concentrations of about 6 µl liter−1 and 7% (0.3 mmol produced), respectively, and decreasing after 192 h to 0.1 µl−1 and 2%, respectively. The gaseous environment markedly affected cell growth. The exponential growth period of suspensions
cultured in flasks closed with cotton plugs and aluminum foil caps started after about 72 h and the stationary phase after
240 h, the cell dry weight reaching its maximum at about threefold the initial weight. Large cell aggregates were found in
flasks closed with cotton plugs, slight aggregation with aluminum closures, and no aggregates with rubber caps. However, hardly
any growth, progressive browning of the suspensions, and the death of most cells occurred in rubber-capped flasks. A type
of closure allowing low gas exchange rates, like aluminum caps, and frequent subcultures thus seems most conducive to rapid
growing, more homogeneous GF 677 cell suspension cultures, and the prevention of aggregates, if undesired.
In Vitro Cellular & Developmental Biology - Plant 04/1995; 31(4):207-210. · 1.50 Impact Factor
ABSTRACT: In vitro proliferation and rooting capacity of San Castrese and Portici apricots (Prunus armeniaca L.) were tested on modified MS medium enriched with varying growth regulator concentrations and sucrose (58.4 mM) or sorbitol (116.8 mM) as main carbon energy sources. The interaction of proliferation and rooting media was also studied.Proliferation of both cultivars was proportional to benzyladenine (BA) concentration and enhanced with sorbitol media. However, 8.8 M BA was often associated with hyperhydricity, particularly when shoots were grown on sucrose media. Newly proliferated shoots elongated better on sorbitol media. The positive influence of sorbitol on proliferation and shoot growth was not due to osmotic effects. Moreover, sorbitol showed a positive carryover effect in hastening rooting of Portici. By contrast, when transferred to sorbitol rooting media, the shoots of both cultivars generally showed low rooting, with short, thick roots.Up to 70% of the plantlets that produced roots in sucrose media enriched with indolebutyric acid were successfully acclimatized when they were dipped in a benomyl (0.075% w/v) suspension before being transplanted with care being taken to prevent over-wetting of soil.
Plant Cell Tissue and Organ Culture 08/1993; 34(3):235-244. · 3.09 Impact Factor
ABSTRACT: The effect of paclobutrazol on in vitro rooting and growth of sour cherry (Prunus cerasus) rootstock CAB 11E clone, of S 749 S 1490 (Prunus persica Prunus kansuensis) hybrid rootstock, and of pear (Pyrus communis), cv. Abb Fetel is reported.PP333 increased rooting of S 749 S 1490 and of Abb Fetel, particularly at a concentration of 0.5 mg/l (a.i.); moreover, it induced a rooting percentage as high as auxin in the former and hastened rooting of the latter. By contrast, paclobutrazol did not affect root production of 11 E.PP333-treated plants had shorter and thicker roots than controls but similar survival rates during acclimatization. Otherwise they grew less than controls during the first part of the acclimatization phase.
Plant Growth Regulation 01/1988; 7(4):237-247. · 1.60 Impact Factor
ABSTRACT: Japanese plum cultivars Obilnaga and Santa Rosa showed different proliferation responses when grown in similar conditions in vitro. This led us to investigate BA uptake by shoots of both cultivars grown for different times (15 hrs, 1, 3, 6, 9, 13, 16 and 20 days) on an incubation medium enriched with 10Ci (370 kBq) 8-[14C]BA/250 ml. The decrease of radioactivity in the medium and its increase in the EtOH-soluble and-insoluble fractions of shoots of both cultivars grown for different times (15 h, 1, 3, 6, 9, 13, 16 and 20 days) on cultivars. Increasing amounts of14CO2 were detected in the culture atmosphere when shoots were grown in gas-tight vials. The type of container closure strongly affected proliferation. From the results reported here it is not possible to state whether different optimal subculture intervals and different proliferation responses of Santa Rosa and Obilnaja cultures are due to different tissue sensitivity to the cytokinin and/or to different metabolic activities. Nevertheless the highest proliferation rates of both plums are clearly related to a drop of EtOH-soluble radioactivity of shoots by the end of subculture.
Plant Cell Tissue and Organ Culture 12/1987; 13(1):49-59. · 3.09 Impact Factor
ABSTRACT: In vitro cultures of three Prunus clones (d. 1869, GF 677 and CAB 11E) were successfully stored at +8, +4 and-3C following the proliferation phase.Survival of cultures was dependent upon interactions of storage temperature, light, and age of subculture. Up to 100% of the cultures survived at the end of the trials after 170 (at +4C) and 200 (at-3C) days storage. Complete dardness appeared more suitable than 16-h (hour) photoperiod for successful storage at-3C for up to 10 months. One or two weeks in normal growth room vefore storage at-3C for up to 10 months. One or two weeks in normal growth room before storage enhanced the survival S-1. The proliferation of the cultures following storage at-3C in the first subculture appeared similar to those under standard growth room conditions.Part of the results were presented as a poster at the 10th Congress of Eucapia in Wegeningen, The Netherlands, 19–24 June 1983.
Plant Cell Tissue and Organ Culture 12/1984; 5(1):73-78. · 3.09 Impact Factor