Frequency Of Bud Formation Research Articles

Influence of Selected Antibiotics on the Tomato Regeneration in In Vitro Cultures

Generally, antimicrobial agents are frequently used in micropropagation techniques to obtain free elite clones or after genetic transformation to select putative transformants. Their successful application minimizes bacterial contamination however; they may be phytotoxic and may diversely affect the regeneration ability in plant tissue cultures. The objective of the current study was to estimate the effects of four antibiotics i.e. ampicillin, carbenicillin, cefotaxime and kanamycin on morphogenesis of three Polish tomato cultivars, cultured on MS medium with phytohormones. In this experiment the ability of tomato cotyledon explants to regenerate entire plants via indirect organogenesis was tested. Among four antibiotics tested, kanamycin was most harmful for the explants. This antibiotic, even at low doses (10-20 mg/L), inhibited tomato morphogenesis. On the other hand, the current study revealed significant influence of different concentrations of ampicillin, carbenicillin, cefotaxime on the frequency of bud formation. While the addition of cefotaxime at low concentration (100-200 mg/L) stimulated the bud formation, its increasing concentration adversely affected the organogenesis of tomato. The results clearly pointed out that carbenicillin and ampicillin at low concentrations (100-400 mg/L) were not only non-toxic, but they promoted bud regeneration. The obtained results show the crucial role not only of use of efficient antibiotics, but also of their proper doses in obtaining successful transformation and regeneration of tomato.
 
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 In press - Online First. Article has been peer reviewed, accepted for publication and published online without pagination. It will receive pagination when the issue will be ready for publishing as a complete number (Volume 47, Issue 3, 2019). The article is searchable and citable by Digital Object Identifier (DOI). DOI link will become active after the article will be included in the complete issue.
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Efficient plant regeneration from leaves of rapeseed (Brassica napus L.): the influence of AgNO3 and genotype

Factors influencing reliable shoot regeneration from leaf explants of rapeseed (Brassica napus L.) were examined. Addition of AgNO(3) to callus induction medium was significantly effective for shoot regeneration in all three genotypes initially tested. When 48 genotypes subsequently were surveyed, a large variation of shoot regenerability was observed, ranging from 100 to 0% in frequency of bud formation and from 7.5 to 0 in the number of buds per explant. A significant correlation (r=0.84) was observed between the frequency of bud formation and the number of buds per explant. The shoot regenerability from leaf explants was not related to that from cotyledonary explants (r=0.28). Histological observations showed that an organized structure developed from calluses produced at vascular bundle tissues after 7 days of culture on callus induction medium, and they developed shoot apical meristems one week after transfer onto shoot induction medium. Regenerated plantlets were obtained 2 months after the initiation of culture and they normally flowered and set seeds. No alterations of morphology or DNA contents were observed in regenerated plants and their S1 progenies.

THE INDUCTION AND REGENERATION OF RABBITEYE BLUEBERRY BUDS

Several factors affecting rabbiteye blueberry (Vaccinium ashei) bud induction, differentiation and plant regeneration were studied. Results indicated that supplementing the induction and subculture medium with NAA and 2ip benefited the induction of blueberry buds, but adding 2ip maintained their ability to differentiate. Plant source, especially genotype, had no effect on the bud differentiation in the long-term culture. The hormones used, NAA, 2ip and ZT, affected the bud differentiation frequency. Among them, 2ip increased the frequency of bud formation. Low-temperature exposure prior to culturing enhanced the bud differentiation frequency of the explant. In the subcultures, we ound that 4300 lux and 5000 lux were the best light intensities for culture. Supplementing the root medium with IBA or NAA increased the formation of roots, but I A performed best.

GROWTH REGULATOR EFFECTS ON BUD INITIATION IN CALLUS CULTURES OF MEDICAGO SATIVA

Influence of growth regulators on bud initiation in callus of alfalfa (Medicago sativa L.) was studied by varying levels and combinations in the first medium of a two‐medium sequence used to obtain whole plants. Callus of tetraploid clone S‐4 (cv. ‘Saranac‘) was initiated from immature ovaries on a modified Blaydes' basal medium containing all combinations of six concentrations (0–36 μM) of kinetin (K), six concentrations (0–44 μM) of naphthaleneacetic acid (NAA), and seven concentrations (0–36 μM) of 2,4‐dichlorophenoxyacetic acid (2,4‐D). After 28 days the callus was challenged to form buds by transfer to the modified Blaydes' medium containing 2.0 g/liter yeast extract and 0.57 mM inositol. No buds were produced in the absence of 2,4‐D in the first medium, and the frequency of bud formation on the second medium was directly proportional to the 2,4‐D concentration in the range 2.3–54 μM in the preceding medium. Buds were produced in the absence of kinetin in the first medium, but its presence in the range 2.3–36 μM markedly increased bud formation. NAA was not required for bud formation, and the budding frequency increased only slightly with increasing NAA concentration in the first medium. Budding of callus of two other alfalfa clones was also influenced by the 2,4‐D concentration in the initial medium. There were several indications that many of the buds were initiated on the first medium and completed development on the second medium. These included the differential effect on budding of combinations of 2,4‐D, NAA and kinetin in the callus initiation medium, the specific media sequence required, and the presence of embryoids on the callus which after transfer to the yeast extract‐inositol medium produced buds.