Interspecific hybridization between B. oleracea inbred lines of head cabbage, Brussels sprouts, kale and B. taurica and inbred lines of rapeseed (B. napus L.) were performed aiming at the development of the new sources of genetic variability of vegetable Brassicas. Using conventional crossings and the embryo-rescue techniques the following interspecific hybrids were developed: 11 genotypes of F1 generation, 18 genotypes of F2 and F1 × F2 generations (produced after self- and cross-pollination of interspecific F1 hybrids), 10 plants of the BC1 generation (resulted from crossing head cabbage cytoplasmic male-sterile lines with interspecific hybrids of the F2 and F1 generations) and 8 plants of BC1 × (F1 × F2). No viable seeds of the BC2 generation (B. oleracea) were obtained due to the strong incompatibility and high mortality of embryos. The morphological characteristics during the vegetative and generative stages, pollen characteristics, seed development and propagation, nuclear DNA contents and genome compositions of interspecific hybrids were analyzed. All the interspecific F1 hybrids were male-fertile with a majority of undeveloped and malformed pollen grains. They showed intermediate values for morphological traits and nuclear DNA contents and had nearly triploid chromosomal numbers (27 to 29) compared with parental lines. The F2 generation had a doubled nuclear DNA content, with 52 and 56 chromosomes, indicating their allohexaploid nature. F2 hybrids were characterized by a high heterosis of morphological characteristics, viable pollen and good seed development. F1 × F2 hybrids were male-fertile with a diversified DNA content and intermediate pollen viability. BC1 plants were male-sterile with an intermediate nuclear DNA content between the F2 and head cabbage, having 28 to 38 chromosomes. Plants of the BC1 × (F1 × F2) generation were in majority male-fertile with 38–46 chromosomes, high seed set, high heterosis and intermediate values for morphological traits. The obtained interspecific hybrids are valuable as new germplasm for improving Brassica-breeding programs.
The strains of bacteria Paenibacillus glucanolyticus, Curtobacterium pusillum and Methylobacterium extorquens were isolated as non-deleterious contaminations from hosta or raspberry tissue cultures. Microshoots of chrysanthemum, gerbera, hosta and rose were inoculated with these bacteria and their influence on shoot multiplication and rooting was evaluated. None of the investigated bacteria caused symptoms of hypersensitivity or vitropathy on the shoot explants at rooting and shoots multiplication. C. pusillum stimulated axillary shoot formation in all studied plant genotypes. Length and number of rose roots and their length were higher but number of roots and their length in chrysanthemum were lower in inoculated than in controls. The number and the length of shoots and roots in gerbera and hosta and the number of shoots in chrysanthemum inoculated with M. extorquens were higher but shoot length of chrysanthemum and rose, and root length of rose were lower as compared with controls. P. glucanolyticus influenced higher number and length of chrysanthemum shoots and root length of chrysanthemum and gerbera than noninoculated control but the number of gerbera and hosta roots was lower and root length of rose was as low as 0.2 cm. All assessed bacteria were able to assimilate atmospheric nitrogen and M. extorquens and P. glucanolyticus were able to produce IAA.
Among the numerous protocols that describe the extraction of DNA, those relating to the isolation of DNA from infected plants, are rare. This study describes a rapid and reliable method of extracting a high quality and quantity of DNA from rhododendron leaves artificially infected with Phytophthora cactorum, P. cambivora, P. cinnamomi, P. citrophthora, and P. plurivora. The use of the modified Doyle and Doyle protocol (1987) allowed us to obtain high quantity and quality DNA (18.26 µg from 100 mg of the fresh weight of infected leaves at the ratios of A 260/280 and A 260/230 -1.83 and 1.72, respectively), suitable for conventional polymerase chain reaction (PCR) and real-time PCR amplifications.
Helleborus is a valuable ornamental plant, flowering in early spring or winter. Its hybrid cultivars can be propagated vegetatively, including in vitro via axillary shoots. One of the obstacles preventing effective micropropagation is the necessity for culture to be kept at a temperature of around 15 o C, which additionally increases costs. Knowledge obtained up to date shows that inoculating plants with bacteria Burkholderia phytofirmans PsJN can increase their tolerance to the non-optimal growth temperature. In this study, we tested whether the bacterium, which is known to produce a relatively high amount of IAA and demonstrates ACC deaminase activity, was able to stimulate Helleborus root formation at a temperature of 23 o C.In our experiment, the microshoots cultured without auxin and not inoculated with PsJN rooted in 83% with 1.7 roots of 0.6 cm long. The microshoots, which were induced to root with auxins IBA 3 mg/L and NAA 1 mg/L but not inoculated, were rooted in 94% with 2.0 roots of 1.1 cm long. A similar result was obtained for the microshoots not rooted on auxin containing medium but inoculated with PsJN -95% rooted shoots with 2.3 roots of 1.2 mm long. The microshoots that were induced to root on the auxins containing medium and then inoculated with PsJN were rooted in 100% with 6.9 roots of 2.1 cm long. Almost all microplants from this treatment acclimatized to greenhouse conditions and grew vigorously, then flowered after winter precooling in a mildly heated greenhouse.
Hypocotyl fragments of Cucumis sativus L. were grown on two basic media: Linsmaier-Skoog's (1964) and White's (1943) modified by Street and McGregor (1952). These media were enriched by addition of some growth regulators (NAA, IAA, 2,4-D) in combination with kinetin. White's basic medium is not suitable for callus culture and for rhisogenesis of cucumber hypocotyls. Linsmaier and Skoog's medium was most suitable for growth of callus. After enrichment of the media with IAA, NAA and 2,4-D differences in the degree of taking root by the explants and callus formation were observed
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.