Assessment of regeneration and transformation in sweet cherry cultivars

The sheer size of the tree is still one of the most relevant cherry-growing related problems. Genetic transformation with phytochrome genes could contribute to the reduction of tree size in cherry. The responses to morphogenesis and genetic transformation were compared in two sweet cherry commercial cultivars and the characterised somaclone HS. Axenic shoot cultures of \u2018Hedelfinger\u2019, \u2018Lapins\u2019 and somaclone HS were grown on BA (6-benzylaminopurine) containing medium. The apical portion of each shoot was cultured in the presence of BA and NAA (naphthalene acetic acid) in the dark. After two weeks the callus formed at the base of each shoot, a 3-4 mm upper stem portion deprived of axillary shoots/buds and intact leaves were subcultured on regeneration medium, in the light. A. tumefaciens (C58C1 pGV3850), carrying the p35SGUSIntron binary vector was used to infect shoots deprived of unfolded leaves and lateral buds by either full immersion or basal dipping in the bacterium suspension. After 21 days under light, all tested explants, except \u2018Lapins\u2019 stems, showed regeneration ability. All reached their maximum regenerative expression within 56 days and \u2018Lapins\u2019 basal callus scored the highest regeneration percentage (50.1%). Basal dipping was chosen as the optimal system to infect the two cultivars and the somaclone which showed a different attitude to produce morphogenic callus. The morphogenic masses kept growing on 50 mg L-1 kanamicine for 40 weeks and the first shoots started to elongate when the BA was reduced by one-fourth. GUS activity was found in the shoot basal cuts and surrounding tissues and this evidence let us deduce that hypothetically transformed cells had chances to take part in either direct or indirect morphogenesis

Shoot Regeneration, in Vitro Performances of Regenerated Shoots and Transient Expression in Morphogenic Explants in Prunus avium cultivar 'Burlat C1'

Biotechnology may represent alternative ways to genetic improvement of sweet cherry exploiting somaclonal variation and genetic transformation. In this paper a method to induce efficient shoot regeneration from somatic explants of \u2018Burlat C1\u2019 is reported: 52.0 % caulogenesis was obtained from basal callus formed after culturing shoot apical portions in the dark. Considering the significant onset of adventitious shoots showing variegated leaves their in vitro performances have been evaluated as compared to green (normal) shoots. The influence of cefotaxime, cefotaxime plus vancomycin and timentin was assessed both for decontamination and regeneration efficiency prior transforming morphogenic masses with A. tumefaciens (C58C1 pDN3514), carrying the rolABC genes from A. rhizogenes, p35GUS-intron visible marker and nptII antibiotic resistance gene. GUS test indicated the presence of transient expression in shoot primordia nevertheless it was not possible to recover transgenic shoots probably due to the formation of chimeric meristem

Influence of thirteen different strains of ericoid endomycorrhizae on rooting and growth of micropropagated azalea mollis

In the wild, most of the Ericaceae are mycorrhized by typical ericoid endomycorrhizae thus overcoming the absence of root hairs and the difficulty of absorption of some nutrients in low pH soils. Many authors studied the relationship between root colonization and soil composition but only a few of them took in consideration the species of the fungi mycorrhizing the roots. Our previous works on Vaccinium pointed out the effects of different fungal strains on rooting and growth of in vitro produced plants. The aim of this research was to study the effect of the inoculum with different fungal strains on rooting, acclimatization and growth of the deciduous Azalea mollis cv. Glowing Embers (Rhododendron japonicum), micropropagated in vitro. Sterile microcuttings, planted on a sterilized turf substrate, were inoculated with Hymenoschiphus ericae, seven different strains of Oidiodendron maius, and some unidentified sterile mycelia, by superimposing the rooting medium on a pure fungal culture in agar. Rooting time and percentage was checked. Plant height and rosette diameter, leaf and shoot number of each plant were measured one year after transferring to ex vitro conditions. All tested strains were able to infect the roots of the azalea, but different effects were shown on microcutting rooting time and percentage. Oidiodendron strains were generally more effective than Hymenoschiphus on growth of established plantlets

Experimental approaches on in vitro grafting in Prunus armeniaca and P. spinosa

An in vitro grafting protocol was established with micropropagated shoots of the apricot cultivars \u2018Caldesi\u2019 and \u2018Alb 3\u2019, (apricot selection from \u2018Cricot\u2019 x \u2018NAJ 53\u2019 cross) and the P. spinosa seedling \u2018PS123\u2019(open pollination from a wild tree). Compatible combinations (homografts) were ascertained by considering vascular continuity between scion and stock, as determined by fast toluidine blue staining procedure, and by restoration of phloem connections as determined by application of 5(6)-carboxyfluorescein (CF) to the scion. 15 days after graft establishment, the differentiation of new xylematic tissue resulting in unification of the vascular elements between stock and scion was observed in all the genotypes which, moreover, showed restoration of active phloem. High correlation between the differentiation of new xylem and the differentiation of new phloem at the graft point was found. Graft-take, however, did not correlate with the scion-stock compatibility, in that heterograft-take was high but did not reflect xylematic continuity or phloematic transport, which were not established in any of the tested scion-stock combination. The use of rooted shoots as rootstock resulted in unsuccessful graft technique

Micropropagation of service tree (Sorbus domestica L.) : role of some factors on in vitro proliferation and rooting, and extra vitro acclimatization

The use of in vitro culture, as a tool of vegetative propagation, contributes to both large scale multiplications of interesting genotypes. Regards explant establishment 100% of both sterile and proliferating explants were obtained cutting the explants from two years old micropropagated donor plants. Two selected lines out of three were stimulated in proliferation from the highest (5.0 ?M) BA concentration. 1000 g l-1 IBA and 2.5 ?M BA enhanced rooting in two selected lines out of three. Regarding extra vitro acclimatization the importance of growing media is often overlooked in scientific reports. Different types of growing media were tested, and the relationships among their chemical and physical properties and plant responses were investigated

Phyllometry and carpometry, chemical and functional characterization of fruits of Sorbus domestica L. (service tree) selections

Service tree (Sorbus domestica L.) belongs to a large genus of plants, that in the past characterized the agricultural landscape of large areas of Europe. In the light of recent acquisitions regarding nutraceutical and functional properties of service fruits in allied Sorbus species, our work aimed at the morphological description, evaluation of fruit quality and functionalnutraceutical properties of the same accessions selected for timber, in order to identify double aptitude plants. Morphological and chemical differences among plant selections were found particularly for titratable acidity and red colour of the skin: bletting contributed to mitigate such differences. Chromatograms obtained by reversed-phase HPLC analysis indicated that the phenolic compounds present in the matrix may be assimilated to three main classes of compounds: gallic acid, its derivative and polymeric tannins. Acids and flavonols were present in much lower quantities this indicating that the main phenolic compounds nature of our service fruit selections were hydrolysable tannins. A linear and positive correlation was found between the two methods, DPPH\u2013EPR and CAB, used to assay antioxidant capacity this indicating that easy to manage DPPH-EPR assay may be used for substrates that are high in phenols as the case of service fruits. Our original hypothesis of wide variability among trees was finally confirmed by discriminant analysis which admitted most of the recorded variables, and showed each plant selection as a case in itself

A PRELIMINARY APPROACH TO ASSESS PEACH FRUIT TEXTURE BY TIME-RESOLVED SPECTROSCOPY (TRS)

Most fruits can be modeled for their internal composition as a diffusive medium at visible and near-infrared wavelengths. The low absorption in this spectral range allows exploiting VIS/NIR spectroscopic techniques to probe non-destructively the internal food properties. Time-resolved reflectance spectroscopy (TRS), in particular, allows the separate, but simultaneous estimation of absorption and scattering coefficients. Absorption and scattering properties give very different information about the medium investigated. The possibility of applying TRS to assess the texture type of peach fruit was tested. To this purpose, an instrument for TRS developed at Politecnico di Milano-Department of Physics, was exploited. At least two cultivars for each peach flesh phenotype (melting, non-melting, stony hard and slow melting) and a total of 30 fruits for each cultivar were analyzed over the spectral range 540-940 nm. The absorption spectra exhibit high values around 550 nm due to the anthocyanins' absorption features. Furthermore, an absorption peak is visible at 670 nm, linked to the chlorophyll a content and then gives an idea about the fruit ripeness (a high chlorophyll content corresponds to a less ripe fruit). With the exception of the cultivar 'Iride', particularly rich in anthocyanins, and 'Ghiaccio', anthocyaninless, the absorption spectra of all of the samples were similar. Concerning the scattering properties of peaches, by considering the equivalent density and the scatter power Mie parameters, it was possible to discriminate between three out of four texture types (melting, slow melting and stony hard). Further improvements may lead to a full discrimination in the future

Peach

The peach is the third most produced temperate tree fruit species behind apple and pear. This diploid species, Prunus persica, is naturally self-pollinating unlike most of the other cultivated Prunus species. Its center of diversity is in China, where it was domesticated. Starting about 3,000 years ago, the peach was moved from China to all temperate and subtropical climates within the Asian continent and then, more than 2,000 years ago, spread to Persia (present day Iran) via the Silk Road and from there throughout Europe. From Europe it was taken by the Spanish and Portuguese explorers to the Americas. It has an extensive history of breeding that has resulted in scion cultivars with adaptability from cold temperate to tropical zones, a ripening season extending for 6\u20138 months, and a wide range of fruit and tree characteristics. Peach has also been crossed with species in the Amygdalus and Prunophora subgenera to produce interspecific rootstocks tolerant to soil and disease problems to which P. persica has limited or no resistance. It is the best known temperate fruit species from a genetics perspective and as a model plant has a large array of genomics tools that are beginning to have an impact on the development of new cultivars

Organogenesi e aspetti della coltura in vitro di cultivar di ciliegio dolce

Sweet cherry cv\u201cHedelfinger\u201d e \u201cBurlat C1\u201d showed different responses to \u2018in vitro\u2019 culture conditions. Shoot regeneration of \u201cHedelfinger\u201doccurred, after several months, from wounded leaflets cultured on TDZ and IAA. Red light enhanced elongation of \u201cHedelfinger\u201d and somaclon \u201cHS\u201d shoots and affected proliferation of somaclon \u201cHS\u201d