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Callus induction on standard type Cymbidium cultivars
Published August 23, 2000
108-110.

Tissue cultured Cymbidium PLBs (protocormlike body) were used as starting material to induce embryogenic callus which could serve as objects of genetic transformation. We obtained callus using two methods. The first method was culturing the PLB segments for one month in liquid MS medium in the presence of 0.5 mg/1 benzyladenine and 0.0...5 mg/1 naphtylacetic acid followed by cultivation on the same composition solid medium with 0.5 g/l activated charcoal for an additional month. Callus formation was observed on 30% of the explants. The second way was to propagate the PLB segments on solid MS medium supplemented with 1 mg/1 thidiazuron. In these cultures we also observed callus formation on 20% of the explants.

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Rhizogenesis in in vitro shoot cultures of passion fruit (Passiflora edulis f. flavicarpa Deg.) is affected by ethylene precursor and by inhibitors
Published March 21, 2001
47-54.

The effects of the ethylene precursor ACC and two inhibitors, AgNO3 and AVG, on root formation were tested in in vitro shoots of passion fruit (Passiflora Midis f.flavicalpa Deg.). The organogenic response was assessed on the basis of percentage of shoot-forming. roots, root number and length. The time course of eth...ylene production was also monitored. ACC inhibited root formation by delaying root emergence and increasine, callus formation at the basis of the shoots. In addition, ACC caused a marked increase in ethylene production, coupled to leaf chlorosis and senescence with lower rooting frequencies, number and length of roots. IAA supplementation increased ethylene production. Both ethylene inhibitors, AgNO3 and AVG, at appropriate concentrations reduced callus formation at the basis of shoots. AVG increased the number of roots per shoot, but drastically reduced length of differentiated roots. Regarding to leaf pigments, ACC promoted a marked reduction on carotenoids and total chlorophyll, whereas AVG and AgNO3 delayed explant senescence and pigments degradation, not differing from IAA supplemented and non-supplemented control treatments. The results confirm previous reports on the beneficial effects of ethylene inhibitors on in vitro rooting and suggest its reliability to be used as an alternative approach to evaluate sensitivity of Passiflora species to ethylene.

 

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Anatomical study of the bud union in „Chip" and „T" budded 'Jonagold' apple trees on MM 106 rootstock
Published May 24, 1999
27-29.

The traditional methods for vegetative propagation of apple and its varieties are the T-budding, and the winter grafting, but this latter way is a difficult and expensive procedure.

In our experiment carried out in the Fruit Tree Nursery Soroksár, the healing process of chip- and T-budded apple trees 'Jonagold' on MM 106 rootstock was ...studied.

The budding (T- and Chip-) was made in the first week of August, samples for microscope examination were taken monthly after this time until leaf fall.

The investigated part of plants was made soft with 48 % HF (hydrogenfluoride), then cross and longitudinal section were made and examined by microscope.

Based on analysis of microscope pictures in case of Chip-budding, it was established, that development had started quickly after budding on the rootstock and scion too. But the callus originated almost entirely from the rootstock tissue as new parenchyma cells fills the gap between the two components of graft (scion and stock), becoming interlocked and allowing for some passage of water and nutrients between the stock and the scion. This quantity of callus in case of T budding was under the scion buds larger, than the Chip-budded unions, where the thickness of callus mass is uniformly thick round the chip. The large mass of callus pushes the scion bud outwards from the shoot axis, which later results in a larger shoot-curvature above the bud union.

Following this process on the Chip-budding it can be observed also, that a continuity of the cambium is established between bud and rootstock. Then the newly formed cambium started typical cambial activity, forming new xylem and phloem.

Later the callus begins to lignify, and it is completed within about 3 months after budding.

 

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The effect of different biostimulators on morphological and biochemical parameters of micropropagated Hosta ’Gold Drop’
Published July 29, 2019
22-29.

During in vitro multiplication of Hosta ‘Gold Drop’, 20 g l-1 sucrose, 5.5 g l-1 agar and 4 concentrations (0.1-0.8 ml l-1) of Ferbanat L, Kelpak, Pentakeep-V were added to half-strength Murashige and Skoog (MS) basal medium. As compared to the control and other biostimulators, plants with lower per...oxidase activity, larger fresh weight, more, longer shoots and roots, larger leaves were developed on medium containing Kelpak. The best concentration was 0.4 ml l-1 for in vitro rooting, shoot formation, plant weight and ex vitro chlorophyll, carotenoid level, peroxidase activity. Pentakeep was the less efficient biostimulator, increasing of its concentration mostly decreased root and shoot values (furthermore, abnormal callus formation was observed, as non-wanted effect), chlorophyll content and sizes (length, width) of leaves, not only during in vitro propagation but also (as after-effect) acclimatization because of the high mortality and weakly developed survivor plants.

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Comparative investigations on protoplast culture of some Brazilian and Hungarian sweet pepper cultivars and hybrids
Published September 13, 1999
39-45.

Cotyledon protoplasts were isolated from 16-18-day-old in vitro grown seedlings of 9 Brazilian and 3 Hungarian pepper varieties and hybrids. Large numbers (average 9.59 X 106 protoplasts g 14 fresh weight) of highly viable (average 87.0%) protoplasts were released using a pectocellulolytic enzyme mixture. Protoplasts were cultured in... K8p mediuni using an alginate disc embedding method. The osmotic pressure of the medium surrounding the alginate-embedded protoplasts was reduced by replenishing the liquid medium at K8p:K8 ratios of 1:0. 2:1, 1:1 in the first. second, and third week, respectively. Initial plating efficiency (IPE) average was 38.5% and after 21 days protoplasts reached microcolonies (15-20 cells) stages. Microcolonies were transferred after 3-4 weeks to a MS-based medium supplemented with 1.0 mg I-1 zeatin, 3.0% (w/v) sucrose, 0.24% (w/v) phytagel and pH 5.8, whereupon they formed callus. Final plating efficiency (FPE) average was 0.29% at a plating density of 1.0 x 105 protoplasts Protoplast-derived calli were cultured on a range of MS-based media supplemented with either BAP, IAA, TDZ; and zeatin. No morphogenic response was observed in any genotype investigated.

 

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Investigation of the in vitro regeneration of mericlones in the caribe variety of carnation
Published September 11, 2001
87-89.

In vitro culture conditions were experimented for the relatively sensitive, but very esthaetic "Caribe" variety of carnation with uniformly dark violet flowers. Regeneration of new plants from shoot apex meristems can be significantly improved by the combined addition of very low amounts of indolebutiric acid, benzyladenine and gibbere...lic acid, dissolved in the Murashige-Skoog nutrient medium. Callus formation as a prerequisite for the induction of somaclonal variability can be achieved successfully with certain molar ratios between 2,4-dichlorophenoxyacetic acid and benzyladenine. Acclimation of the obtained mericlones to the ex vitro conditions was also evaluated.

 

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Dr. Ottó Orsós, the forgotten Hungarian pioneer in plant tissue culture
Published March 14, 2005
9-13.

The knowledge of tissue culture deserves attention in respect of understanding the development of universal biology. This study intends to contribute to the past of the plant tissue culture by such data of the history of science which have been unprocessed so far. It seems that the life-work of the Hungarian biologist, Dr. Ottó Orsós is a mis...sing and essential link between those early plant hormone researchers and the representatives of the pioneers of tissue culture schools who have contributed substantially to the development of the modern in vitro plant morphogenesis and plant cell biology. Orsós cultured kohlrabi tuber cubes on White culture medium in a sterile manner. This way, he could efficiently direct the in vitro morphogenesis of the kohlrabi, the regeneration of its shoot and root, and the formation and steps to subculture of pure callus tissues in 1938. He supported the correctness of its statements by means of detailed anatomical examinations. Orsós successfully rooted and aclimatized complete regenerated plants. We may as well call the above system — in remembrance of the creators of the original concept — "Haberlandt-Orsós model". Between the publishing of his main paper in 1938 and 2003, a period of 65 years has lapsed. On the occasion of this anniversary, we bow before this forgotten pioneer.

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Studies on the alkaloid production of genetically transformed and non-transformed cultures of Lobelia inflata L.
Published June 6, 2001
65-71.

The investigations of the growth and alkaloid production of cell suspension-, callus-, organized- and hairy root cultures from Lobelia inflata L. proved that these cultures are able to synthesize the characteristic piperidine alkaloids of the intact plant. Alkaloid precursor amino acids (Phe, Lys) and plant growth regulators affect not... only the growth and differentiation of tissue cultures but also their secondary metabolism. The synthetic regulator Sz/I I combined with Phe increased the total alkaloid content considerably in callus- and organized cultures; regulator Sz/28 especially increased the lobeline content (in organized cultures in response to Lys, in callus tissues as a result of Phe application). With the aim of optimizing growth and alkaloid production of the genetically transformed hairy root cultures of Lobelia inflata L. we studied the effect of some growth regulators (NAA, IAA, kinetin) and precursor amino acids (Lys, Phe). The kinetin had inhibiting effect on the growth and lobeline production of the hairy roots. The IAA and NAA increased the biomass formation and lobeline production. The highest lobeline level was detected in tissues cultivated on hormone-free medium containing Phe.

 

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Influence of different growth regulators on the in vitro morphogenesis of an ornamental variety of carnation
Published October 20, 2003
55-57.

Callus formation, as a prerequisite for the induction of somaclonal variability, was achieved successfully with certain molar ratios between 2,4-dichlorophenoxyacetic acid and benzyladenine. Regeneration of new plants from shoot apex meristems could be significantly improved by the combined addition of very low amounts of indolebutiric acid, be...nzyladenine and gibberelic acid, dissolved in the Murashige-Skoog nutrient medium. These in vitro treatments may contribute to a more efficient micropropagation of the Rimini variety of carnation.

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