Pollen Morphology of Some Species of the Genus Sansevieria Petagna (Asparagaceae)

Pollen grains of 15 species of the genus Sansevieria were examined using light and scanning electron microscopy. The pollen grains were single, but dyads were also found. The basic shape of the pollen grains (with chemical treatment) was subprolate, prolate and prolate-spheroidal and the pollen grains were large (> 50 mm). The pollen grains observed in SEM were prolate-spheroidal, subprolate, prolate and perprolate. The aperture occupied nearly the entire distal hemisphere. The surface of non-apertural areas was microreticulate, psilate-perforate, fossulate and verrucate. The surface of the apertural area was psilate-perforate-verrucate, microreticulate-verrucategemmate and psilate-perforate. The tectum was homogeneous, with perforations. Our results suggest that some species cannot be separated based on pollen grain morphology, but only may be categorized into their groups. The present study investigated pollen grain morphology in eleven species for the first time in terms of pollen micromorphology and provided some important new data.

Effect of Fluridone on Some Physiological and Qualitative Features of Ripening Tomato Fruit

In tomato fruits, chlorophyll, lycopene and ß-carotene are mostly responsible for the color. During ripening of tomato fruits, the color of the pericarp changes from green to red as chlorophyll is degraded and carotenoids accumulate. These changes are associated with an increase in respiration and ethylene production. Carotenoid biosynthesis pathway in plants can be disturbed by herbicide fluridone (1-methyl-3-phenyl-5-[3-trifluoromethyl(phenyl)]- 4(1H)-pyridinone), which inhibits the activity of phytoene desaturase, an enzyme responsible for conversion of phytoene to phytofluene. Fluridone is also used as an inhibitor of biosynthesis of abscisic acid (ABA) and strigolactones, and it reduces chlorophyll production in plants. In our research we studied the effect of fluridone on some physiological parameters, such as color, firmness, ethylene production, lycopene and chlorophyll content during ripening of the tomato fruit. Tomato plants cv. Altadena (Syngenta) were cultivated in a greenhouse in controlled temperature and both immature and mature fruits were used for the experiments, performed between August and November 2016. Fluridone at concentrations of 0.1% and 1.0% in lanolin paste was applied as a 2-3 mm stripe from the top to the base of tomato fruits, and as a control a stripe of lanolin was applied in the same way on the opposite side of the fruits. Fluridone at a concentration of 1.0% greatly inhibited lycopene accumulation in the pericarp of tomato fruits from the treated side. The measurements of fruit firmness have shown no significant differences between firmness of the part of the tomato fruits treated with fluridone, and the non-treated ones. Tomato fruits treated with fluridone produced amounts of ethylene similar to those found in control tissues on the opposite side of the same fruit. Fluridone delayed chlorophyll degradation in tomato fruits. The metabolic significance of these findings is discussed with the role of carotenogenesis inhibition in tomato fruit ripening.

Production and Characterization of Tissue Cultures of Four Crocus Species from the Carpathian Basin

We aimed to produce tissue cultures and plant regeneration from endangered Crocus species: C. scepusiensis, C. tommasinianus, C. vittatus (“Verni” series of the genus) and C. banaticus. For initiation of cultures we used a plant growth regulator (PGR) combination used for in vitro culture of saffron and its relatives: 10 mg L-1 α-naphthaleneacetic acid (NAA) and 1 mg L-1 6-benzyladenine (BA). Shoot tips of young seedlings (C. scepusiensis) and corms (for the rest of species) were used as explants. C. scepusiensis explants developed into organogenic calli. On media with decreased NAA and with or without increased BA concentration, calli produced stigma-like structures and/or shoots and whole plants. In the other species, callus initiation medium induced callus formation with abundant somatic embryos. In C. tommasinianus, embryos developed shoots when auxin content of medium was decreased. In C. banaticus, a decrease of auxin with or without an increase in cytokinin content led to shoot or whole plant regeneration, as in C. scepusiensis. In the case of C. vittatus and C. banaticus, initiation and/or maintenance of cultures on indole-3-butyric acid (IBA) and increased sucrose concentration stimulated whole plant regeneration and in vitro cormlet development. C. scepusiensis and the rest of cultures (organogenic vs. embryogenic) differed at the biochemical level: C. scepusiensis cultures had higher (yet still low) enzymatic antioxidant (catalase, peroxidase) activities. With respect to catalase isoenzyme patterns, C. banaticus was different from the rest of cultures, demonstrating its distinct taxonomical position. Besides germplasm preservation use of the present cultures, they have a potential biotechnological value.

Chromosome Numbers in Hieracium (Asteraceae) from Central and Southeastern Europe III

Chromosome numbers for 13 species of Hieracium L. s.str. from Bulgaria, Macedonia, Poland and Romania are given and their metaphase plates are illustrated. Chromosome numbers are published for the first time for H. djimilense s.lat. 2n=3x=27, H. fiekii R. Uechtr. 2n=3x=27, H. glabrescens (F. W. Schultz) Murr 2n=3x=27, H. juranomorphum Zahn 2n=3x=27, H. sparsiflorum subsp. sparsiceps Zahn 2n=3x=27 and H. sparsum subsp. naegelianiforme Behr & Zahn 2n=3x=27.

Cloning, Expression and Genetic Transformation of Sucrose Phosphate Synthase (Sps) Gene in Saccharum Spontaneum L.

Sucrose phosphate synthase (SPS) is a key enzyme catalyzing sucrose metabolism in plants. In this study, we isolated the SPS cDNA from Saccharum spontaneum and designated as SsSPS (GenBank accession no. MF398541). The full-length of SsSPS cDNA was 4153-bp with an opening reading frame (ORF) of 3132 nucleotides, which encoded a 1043-amino acid protein. The nucleotide sequences alignment showed that it had 98%, 97% and 87% homology with S. officinarum, Setaria italica and Lolium perenne, respectively. Moreover, the SsSPS was detected to express in leaf and stem tissues of S. spontaneum and exhibited a predominant expression in the stem tissue. However, there was no significant difference in the expression level of SsSPS between young leaves and mature ones. Additionally, we generated transgenic S. spontaneum using Agrobacterium-mediated transformation. Our data will provide a valuable foundation for further study of the potential role of SPS in plants.

The Ability of Spontaneous Autogamy in Four Orchid Species: Cephalanthera Rubra, Neottia Ovata, Gymnadenia Conopsea, and Platanthera Bifolia

The breeding system in Orchidaceae generates many questions about the selfing potential of its representatives. We investigated the ability of spontaneous autogamy of four orchid species: Cephalanthera rubra and Neottia ovata of the Neottieae tribe and Gymnadenia conopsea and Platanthera bifolia of the Orchideae tribe. These species represent diverse specializations of the gynostemium architecture. The self-compatibility and properties of autogamous seeds were determined in a bagging experiment and seed development analysis. After induced autogamy, a high level of fruiting (80-100%) was noted in all of the four study species. C. rubra, N. ovata, and G. conopsea are completely self-compatible, and P. bifolia is suggested to be partially self-compatible. If autogamy occurred, inbreeding depression and resource limitation on seed development appeared only in the two Orchideae species. Independent of flower specialization, both Neottieae species and P. bifolia were completely allogamous, whereas G. conopsea could be facultatively autogamous.

A Low Ratio of Red/Far-Red in the Light Spectrum Accelerates Senescence in Nest Leaves of Platycerium Bifurcatum

The fern Platycerium bifurcatum is a valuable component of the flora of tropical forests, where degradation of local ecosystems and changes in lighting conditions occur due to the increasing anthropogenic pressure. In ferns, phytochrome mechanism responsible for the response to changes in the value of R/FR differs from the mechanism observed in spermatophytes. This study analyzed the course of ontogenesis of nest leaves in P. bifurcatum at two values of the R/FR ratio, corresponding to shadow conditions (low R/FR) and intense insolation (high R/FR). The work used only non-destructive research analysis, such as measurements of reflectance of radiation from the leaves, their blue-green and red fluorescence, and the chlorophyll a fluorescence kinetics. This allowed tracing the development and aging processes in the same leaves. Nest leaves are characterized by short, intense growth and rapid senescence. The study identified four stages of development of the studied leaves related to morphological and anatomical structure and changing photochemical efficiency of PSII. Under the high R/FR ratio, the rate of ontogenesis of the leaf lamina was much slower than under the low R/FR value. As shown, the rapid aging of the leaves was correlated with faster decline of the chlorophyll content. It was shown that leaf senescence was accompanied by accumulation of polyphenols, anthocyanins and carotenoids on the basis of reflectance and fluorescence measurements in the blue-green range.

Chromosome Numbers in 11 Species of Taraxacum Section Erythrosperma Dt. from Poland

Karyology of eleven species of Taraxacum sect. Erythrosperma from Poland has been studied. Somatic chromosome numbers are given for the following species: T. bellicum, T. brachyglossum, T. cristatum, T. disseminatum, T. dissimile, T. lacistophyllum, T. parnassicum, T. plumbeum, T. proximum, T. scanicum, and T. tenuilobum. Although the hypertriploid chromosome number was previously reported in Poland for T. lacistophyllum, T. parnassicum, T. scanicum, and T. tenuilobum, we proved the triploid chromosome number 2n = 24 in all the species investigated, which is consistent with the data reported from other regions of Europe. The chromosome numbers of T. bellicum, T. cristatum, T. disseminatum, T. dissimile, T. plumbeum, and T. proximum growing in Poland are published for the first time.

Polyamine Plays a Role in Subculture Growth of in Vitro Callus of Indica Rice

In vitroembryogenic callus is a critical factor for genetic transformation of rice, especially for indica varieties. In this study, we investigated the relationship between polyamines, including putrescine (Put), spermidine (Spd) and spermine (Spm), and callus browning, and we studied the effect of exogenous Put on callus regeneration and on the content of endogenous polyamines. In addition, the expression levels of arginine decarboxylase gene (Adc1) and S-adenosylmethionine decarboxylase gene (Samdc) in embryogenic callus were studied by quantitative Real-time PCR analysis. The results showed that the contents of endogenous Put and Spd in the browning callus were significantly lower than those in normal callus. Exogenous Put could effectively improve the growing state of callus of indica rice and enhance the development of embryogenic callus. The content of endogenous polyamines in embryogenic callus, especially Spd and Spm, was increased after addition of exogenous Put. Additionally, exogenous Put also had an obvious impact on the expression levels ofAdc1but partial effect on the expression levels ofSamdcgene. This study could increase the knowledge of both embryogenic callus induction and polyamine catabolism in callus in indica rice.

Salinity Has no Effect on Polysomatic Pattern in Seedlings of Trifolium pratense and T. repens

Endopolyploidy is a condition of a cell containing reduplicated genetic material in its nucleus. Cells with the nuclei of different ploidy levels are often present within a single polysomatic organism. Endoreduplication is thus a modified cell cycle that omits cytokinesis and leads to chromatin replication in the endopolyploid cells. This study aimed to research the effect of salinity on endopolyploidy ofTrifolium pratenseandT. repens. Both species are important pasture legumes and belong to the genusFabaceaewith the well documented endopolyploidy occurence. Endopolyploidy levels in the seedlings treated with 0, 30, 60, 90 and 120 mM NaCl were investigated by flow cytometry. The seedling organs were evaluated during three ontogeny stages. The cytometric data plotted on a histogram showed the presence of 2C-16C nuclei inT. pratenseand 2C-8C inT. repens. The hypothesis that salinity induces additional endocycles was not confirmed. Our results show that the distribution of nuclei among ploidy levels does not differ markedly between the treatment groups and the control ones. Additionally, only minor changes were observed among the endoreduplication indexes (EI) of plant organs after exposure to various salt concentrations. Endopolyploidy patterns within the salt-treated seedlings during ontogeny are similar to the controls. We suggest that endopolyploidy inTrifoliumspecies is a conserved genetic trait, rather than an adaptation to salinity stress. The analyses of the roots ofT. pratenseat stage III show that with the increased concentrations of NaCl the length of roots decreased, but no evident changes in endopolyploidy occured.