Micropropagation of Tulip via Somatic Embryogenesis

An effective method of tulip regeneration via somatic embryogenesis (SE) was developed. Explants, flower stem slices excised from cooled bulbs were incubated in darkness on MS modified media containing auxins alone (2,4-dichlorophenoxyacetic acid—2,4-D, 1-naphthalene acetic acid—NAA and 4-amino-3,5,6-trichloro-2-pyridine carboxylic acid—picloram) or combined with thidiazuron (TDZ) at 0.1 and 0.5 mg L−1. Yellowish-white callus with a granular structure was developed in the presence of all auxins on the cut surface from the tissues of the vascular bundles. From this, lines of embryogenic calli were derived. The addition of TDZ to the medium with auxins significantly stimulated somatic embryo formation. Cyclic and the most intensive proliferation of embryogenic callus as well as embryo formation was obtained in the presence of 2,4-D at 0.1 mg L−1 combined with TDZ at 0.5 mg L−1. Addition of proline enhanced either callus proliferation rate or frequency of embryo formation. The best quality embryos with cotyledons longer than 10 mm able to form bulbs were recorded when TDZ was replaced with 6-benzylaminopurine (BAP) at the concentration of 0.1 mg L−1. Histomorphology showed that the development of somatic embryos could have either external or internal origins. Embryos of external origin were initiated by cell division on the edge of embryogenic calli. Embryos of internal origin resulted from the division of parenchyma cells inside the tissue. Embryonic cells were characterized by their small volume, regular shape, dense cytoplasm and large nuclei. The globular embryos were covered by a distinct layer of periderm. Then, the embryos developed into structures having leaf-shaped cotyledons with a procambial strand and a sideward-orientated meristem of the vegetative apex (stolon). Cotyledon embryos did not show vascular connections with the parent tissue, and they did not develop embryonic roots

Phytoplasma detection in rose shoots propagated in vitro

The results of PCR examination indicated that during two years of tissue culture at standard conditions, on the medium with BAP 1 mg l-1 and continuous temperature of 20oC, phytoplasma could be detected in diseased plants of rose cv Sacha and Jazz. In the second year of micropropagation phytoplasma detection rate in tissues of infected roses increased and was relatively higher than in the first one. To test whether phytoplasmas are sensitive to temperature and light intensity, phytoplasma-affected micropropagated rose plants were grown on medium with BAP 1.0 or 0.5 mg l-1 and at the temperature of 4, 15, 20 or 25oC in darkness or in the light. PCR analysis indicated that phytoplasma detection was not effected by these conditions during 4 weeks of culturing. However, phytoplasma was not detectable in rose plants after 8 weeks culturing on the same medium without transplanting. Micropropagated rose shoots maintained on medium with Gentamycin or Baytril at the concentration of 25.0 or 50.0 mg l-1 had reduced growth and were chlorotic. However, no direct effect of applied antibiotics on phytoplasma detection was evidenced

Effect of growth retardants, cytokinins and auxins on the multiplication and rooting in vitro of Alstroemeria × hybrida "Juanita"

Rhizome cultures of “Jiianita” Polish cultivar of Alstroemeria × hybrida were used to enhance an effectiveness of micropropagation method of new cultivars and selections. The effect of cytokinins (BAP, kinetin and 2iP), auxins (IAA, IBA and NAA), growth retardants (paclobutrazol and flurprimidol alone or in combination were studied in relation to rhizome branching. aerial shoot production and rooting of rhizome. The greatest number of aerial shoots as well as the shortest shoots were observed at the highest BAP concentration (6 mg l-1). However, the rhizonies had the poorest rooting ability. BAP at low concentrations combined with kinetin or 2iP also strongly stimulated aerial shoot formation and rhizome branching. Unfortunately. those shoots were of poor qualily. Application of BAP at low concentration with paclobutrazol (0,1–0,5 mg l-1) or flurprimidol (0,01–1 mg l-1) in presence of 1 mg l-1 NAA resulted in high number of aerial shoots (5–6), reduction of their length and higher rooting ability of the rhizomes. Growth retardants applied with NAA strongly stimulated formation of the roots but suppressed their elongation

Nuclear DNA Content, Selected Morphological and Anatomical Traits of <i>Narcissus</i> Cultivars and Breeding Clones

The genus Narcissus belongs to the family Amaryllidaceae. This genus has been the subject of numerous cytological and cytometric studies and have shown enormous variation in terms of genome size, ploidy level, and even the basic chromosome number. The basic chromosome numbers are 5 or 7, but 10, 11, and 12 have been recorded as well. Most narcissus cultivars are euploid tetraploids. There are also numerous triploids. Some cultivars are aneuploid such as tetraploids or triploids, with missing chromosomes or possessing additional chromosomes. Due to their very complex parentage, cultivars have various numbers of chromosomes not found in the species. In this publication, we present a study on the genome size and assessment of the likely ploidy level of 38 cultivars and breeding clones of Narcissus in relation to their selected morphological traits and information on their parental forms. For the first time, 12 Polish cultivars and breeding clones of narcissus were the subject of such an evaluation. Perianth diameter, leaf length, and width were evaluated and rated with notes according to the descriptor of the International Union for the Protection of New Varieties of Plants. Stomatal density and stomata length were measured using light microscopy. Analysis of genome size was carried out using flow cytometry. For three selected genotypes, the chromosome number was counted. Our results lead to the general conclusion that the morphological traits studied and nuclear DNA content can be useful for determining the possible ploidy level of narcissi. The information on the origin and parental forms of narcissi can be helpful in determining the ploidy level of narcissi. However, clear confirmation of ploidy level requires verification of chromosome number and preferably karyotyping. The results obtained are a prelude to further studies

Pomological Characteristics and Ploidy Levels of Japanese Plum (Prunus salicina Lindl.) Cultivars Preserved in Poland

Research on the resistance to frost, susceptibility to sharka, flowering biology, fruit setting, yield, and ploidy levels of 36 Japanese plum cultivars (mostly hybrids of Prunus salicina with Prunus cerasifera) were carried out in 2015–2020 at the Experimental Orchard located in Dąbrowice near Skierniewice. Relatively mild winters with sporadic temperature drops to nearly −21 °C in January of 2017 and 2018 caused slight damage to several cultivars of Japanese plum insufficiently resistant to frost. The trees of most cultivars remained healthy, with no signs of damage. ‘Barkhatnaya’ and ‘Tatyana’ cultivars turned out to be very susceptible to sharka. ‘Herkules’ trees were the most vigorous. ‘Barkhatnaja’, ‘Blue Gigant’, ‘Shater’, and ‘Tatyana’ trees were characterized by weak growth. The trees of Japanese plum started flowering early, usually in the first or second decade of April. Most of the cultivars belonged to early season cultivars, the fruits of which ripened in July. Based on the assessment of tree productivity, ‘Barkhatnaya’, ‘Inese’, ‘Shater’, ‘Tatyana’, and ‘Vanier’ are the best for growing in the climate of Central Europe. ‘Tsernushka’, ‘Chuk’, ‘Dofi Sandra’, ‘Early Golden’, ‘Ewierch Rannyj’, ‘Yevraziya’, ‘Gek’, ‘General’, ‘Kometa’, ‘Kometa Late’, ‘Maschenka’, and ‘Naidyona’ trees also yielded well. ‘Blue Gigant’, ‘Black Amber’, and ‘Herkules’ had the largest fruits, and ‘Chuk’ and ‘Inese’ cultivars produced the smallest fruits. Among the assessed Japanese plum cultivars, those with round fruit, dark skin with various shades of purple, yellow flesh, and A cytometric analysis showed that almost all cultivars are diploid, except for ‘Herkules’ (possibly pentaploid) and ‘Yevraziya’ (possibly hexaploid or aneuploid)

Study on usability of Fusarium oxysporum Schlecht.f.sp. tulipae Apt. metabolites for screening for basal rot resistance in tulip

The usefulness of fungus culture filtrates and fusaric acid as selecting agents for Fusarium resistance breeding in tulip was examined on in vitro cultures of shoots and embryonic calli of seven tulip genotypes differing in resistance to Fusarium oxysporum Schlecht. f. sp. tulipae Apt. (F.o.t.) and four virulent F.o.t. isolates. Fusaric acid influenced the shoot growth of all cultivars tested in a similar way, irrespectively of their greenhouse resistance to basal rot. Also, the sensitivity of calli of the cultivars studied to fusaric acid did not correspond with their resistance to F.o.t. evaluated in the greenhouse screening. The phytotoxity of F.o.t. culture filtrates did not depend on their fusaric acid contents. There was a negative correlation between cultivar's resistance to F.o.t in greenhouse tests and the sensitivity of their shoots to fungus culture filtrates in in vitro tests. This indicates that defence mechanism against F.o.t. in tulip tissue may have a nature of hypersensitive response. Considering the results of our study, it may be concluded that the use of fusaric acid or fungus culture filtrates for the in vitro selection of somaclones resistant to F.o.t. in tulip is not feasible

Development of embryoids by microspore and anther cultures of red beet (Beta vulgaris L. subsp. vulgaris)

So far there is no information about receiving red beet androgenic embryos by androgenesis. Several factors were tested which affected this process: starch accumulation in microspores, correlation between bud length and microsporogenesis course, induction and regeneration medium composition. Ploidy level of obtained regenerants were evaluated. Treating anthers with α-amylase or watering donor plants with gibberellin increased number of obtained androgenic embryos. The highest percentage (80%) of microspores at uninuclear stage appeared in buds with 1.3-1.5 mm. The B5 medium with 100 g·L-1 sucrose and 0.1 mg·L-1 2,4-D (2, 4-dichlorophenoxyacetic acid) proved to be better for inducing androgenesis than MS medium supplemented with 0.2 mg·L-1 BAP (6-benzylaminopurine) and 0.5 mg·L-1 IAA (indole-3-acetic acid). First androgenic embryos were placed on B5 medium without plant growth regulators and then on MS medium containing 0.2 mg·L-1 BAP and 1 mg·L-1 NAA (α-naphthaleneacetic acid). Androgenic embryos died on B5 regeneration medium without plant growth regulators. On MS medium first shoots and callus with and without roots were obtained. Rosettes withered during following passages whereas callus tissue developed further. The quantity of DNA in this tissue equivalent to 4X chromosomes

Influence of Polyamines on Red Beet (<i>Beta vulgaris</i> L. ssp. <i>vulgaris</i>) Gynogenesis

The influence of polyamines (PAs), putrescine (Put) and spermidine (Spd) on the efficiency of gynogenesis in ovule cultures of red beet (syn. beetroot) (Beta vulgaris L. vulgaris) cultivar “Czerwona Kula” and breeding accessions no. 3/2010 and no. 7/2008 was investigated. The effect of Put on the process of plant regeneration from gynogenetic embryos was studied. The response to the applied PAs was strongly dependent on the genotype. In “Czerwona Kula”, an increase in the number of obtained embryos was achieved by using each of the two PAs in the B5 medium. The effect of Spd was stronger. Put added to the regeneration medium at the concentration of 0.5 mg L−1 increased the number of obtained plants. All shoots placed on the rooting medium supplemented with 160 mg L−1 Put formed roots. The distribution of ploidy and homozygosity of gynogenetic plants depended on the genotype. Of the tested genotypes, the highest number of haploid plants, 68%, was obtained in red beet “Czerwona Kula”. The highest percentage of homozygotes, 69% for the glucose phosphate isomerase (GPI, E.C.5.3.1.9) isoenzyme and 100% for the aspartate aminotransferase (AAT, E.C.2.6.1.1) isoenzyme, was obtained in the population of gynogenetic plants of cultivar “Czerwona Kula”