Utjecaj tipa posude na brzinu mikrorazmnožavanja divlje trešnje

Experiments were carried out to investigate the growth response of wild cherry shoots inoculated into two container types (test tubes, 30 X 160 mm and Erlenmeyer flasks, 100 ml), possessing identical quality and quantity of medium (mod. WPM medium supplemented with BA, IBA and GA3) per shoot, the same opening size, glass and closure type and external environment, but different air volume and surface area. The shoot multiplication of all the six genotypes tested was significantly higher (P < 0.01) in Erlenmeyer flasks in comparison with test tubes.Istražen je utjecaj dva tipa posuda za kultiviranje na rast izdanaka divlje trešnje (Prunus avium L.) u kulturi in vitro. Praćena je stopa multiplikacije u epruvetama veličine 30 X 160 mm i tikvicama po Erlen- meyeru od 100 ml na mod. WPM mediju uz dodatak 2,2 pM BA, 2,5 juM IBA i 0,3 iJtM GA3. Sastav i sadržaj medija po eksplantatu te vrsta stakla, promjer otvora i tip zatvaranja bili su identični. Volumen zraka po eksplantatu bio je veći u epruvetama, dok je površina medija po eksplantatu bila veća u tikvicama. Kod svib šest istraženih genotipova uočena je signifikantno veća stopa umnožavanja (P < 0,01) izdanaka uzgajanih u Erlenmeyerovim tikvicama u usporedbi s epruvetama

Differentiation and morphogenetic potential of Allium commutatum Guss. callus tissue

Differentiation and morphogenetic potential of Allium commutatum Guss. callus tissue was investigated in five subcultures. Callus tissue was derived from root tips of in vitro grown seedlings and maintained on MS medium supplemented with 3% sucrose, 0.8% agar, 4.5 μM 2,4-D and 4.6 μM kinetin. Pieces of calli were subcultured on media with different concentrations and combinations of 2,4-D (1.0,2.5 and 5.0 μM) and kinetin (1.0, 5.0 and 25.0 μM), or without them. After six weeks, the relative increase of callus fresh weight, morphological and histological characteristics as well as the induction of adventitious shoots and roots were investigated. Histological analysis of callui from the 1st subculture showed that callus predominantly consisted of parenchymatous cells surrounded with peripheral meristematic regions. Tracheidal elements, individual and arranged in rows, were observed in all calli investigated. The best callus growth was achieved on media containing 2.5 μM 2,4-D alone or in combination with kinetin (1.0 and 5.0 pM). Addition of kinetin to the nutrient medium stimulated adventitious shoot induction. The shoot formation was improved in later subcultures. The highest number of shoots developed on media supplemented with 5.0 μM kinetin alone or in combination with 1.0 μM 2,4-D, as well as on media with 25.0 μM kinetin alone or in combination with 1.0 or 2.5 μM 2,4-D. The induction of adventitious roots was observed during all subcultures on all media tested

Rast i razvitak u kulturi hrastova lužnjaka (Quercus robur) i kitnjaka (Q. petraea) in vitro

Experiments were carried out to establish an initial culture of Quercus robur and Q. petraea. Apical and axillary buds, taken from seedlings and young plants (up to two years), were used as initial explants for the establishment of culture. The buds were satisfactorily disinfected by successive use of chlorine products and mercuric chloride. Three nutrient media were used: mod. De Fossard medium, ACM medium and mod. WPM medium. Various concentrations of hormones BA, KIN, 2iP, NAA, IBA and GA, were added to all media investigated. Elongation of cultured axillary and apical buds and in some cases adventitious bud induction were achieved when ACM and mod. WPM media were used. Age of explants used did not have an inhibitory effect on positive reaction obtained on both media.Istraženi su uvjeti za uspješno uvođenje eksplantata hrasta lužnjaka (Quercus robur) i kitnjaka (Q. petraea) u kulturi in vitro. Kao početni eksplantati korišteni su vršni i aksilarni pupovi klijanaca i mladih biljaka starih od 10 dana do dvije godine. Pupovi su uspješno sterilizirani klornim preparatom Izosan-G (l°/o) i živinim kloridom (1%). Ispitana je reakcija eksplantata na tri osnovne hranidbene podloge: mod. De Fossard, ACM i mod. WPM i nekoliko regulatora rastenja (BA, KIN, 2iP, NAA, IBA i GA,) u različitim koncentracijama i kombinacijama. Najpogodniji medij za produžni rast i normalni razvoj izdanaka bio je mod. WPM s 2,2 pM BA, 2,5 p,M IBA i 0,3 pM GA.,. Međutim, najveći postotak produljenih izdanaka dobiven je na mediju ACM uz dodatak BA (0,4—2,2 pM), KIN (0,4—0,9 pM), 2iP (0,5 pM) i NAA (0,05 pM). U kulturama je opaženo i zametanje adventivnih pupova na proksimalnoj strani eksplantata na sva tri ispitana medija. Kultura hrasta lužnjaka bila je uspješnija u odnosu na kulturu hrasta kitnjaka u većini usporednih pokusa

Effects of osmotic stress on antioxidative system of duckweed (Lemna minor L)

Background and Purpose: It is known that osmotic stress may cause damage to cells by inducing active oxygen species production or by disrupting detoxification mechanisms. We hypothesize that increased activity of antioxidant enzymes in duckweed (Lemna minor L.) provides a mechanism of tolerance to osmotic stress. Material and Methods: Plants were subjected to NaCl- (50 mM), mannitol- (50 and 100 mM) and polyethylene glycol-mediated osmotic stress (PEG, 50 mM) for a period of 15 days. The responses of antioxidative system including also changes in growth, proline content and the extent of oxidative damage in terms of malondialdehyde, H2O2 and chlorophyll a to chlorophyll b (chl a/b) and chlorophyll a+b to carotenoids (chl a+b/car) ratios were studied. Results and Conclusion: Iso-osmolar concentrations of salt and mannitol significantly reduced relative growth rate compared to control plants while osmotic shockmediated by PEG caused complete cessation of growth. Proline content increased with the severity of osmotic stress showing the highest values in PEG-treated plants. The proline accumulation upon PEG stress was paralleled by equal increase of ascorbic acid pool. Catalase, ascorbate peroxidase and non-specific peroxidase activities showed considerable increase under all osmotic agents, especially PEG. The increased enzyme activities coincided with unchanged H2O2 levels, chl a/b and chl a+b/car under mannitol and salt stress. Despite the highest induction of antioxidative defense, a marked increase in lipid peroxidation and H2O2 level as well as decrease of chl a/b and chl a+b/car accompanied PEG treatment. These results suggested that induction of antioxidant defences is at least one component of the tolerance mechanism of plants to long-term osmotic stress

Cytogenetical investigations of Croatian stenoendemic species Fibigia triquetra (Brassicaceae)

This paper concerns the cytogenetic investigation of the Croatian endemic species Fibigia triquetra (DC.) Boiss. (Brassicaceae). The number of chromosomes in all investigated cells from three populations of Fibigia triquetra was 2n=2x=!6. Chromosomes were small and ranged from submetacentrics to acrocentrics. One chromosome pair had a relatively small satellite. Although meiosis was not completely regular, irregularities were not very frequent. Low pollen germination rate was probably due to these irregularities. As the species is perennial, weakness of seed germination seems not to be important for its survival

Cytogenetical investigations of Croatian stenoendemic species Fibigia triquetra (Brassicaceae)

This paper concerns the cytogenetic investigation of the Croatian endemic species Fibigia triquetra (DC.) Boiss. (Brassicaceae). The number of chromosomes in all investigated cells from three populations of Fibigia triquetra was 2n=2x=!6. Chromosomes were small and ranged from submetacentrics to acrocentrics. One chromosome pair had a relatively small satellite. Although meiosis was not completely regular, irregularities were not very frequent. Low pollen germination rate was probably due to these irregularities. As the species is perennial, weakness of seed germination seems not to be important for its survival

Differentiation and morphogenetic potential of Allium commutatum Guss. callus tissue

Differentiation and morphogenetic potential of Allium commutatum Guss. callus tissue was investigated in five subcultures. Callus tissue was derived from root tips of in vitro grown seedlings and maintained on MS medium supplemented with 3% sucrose, 0.8% agar, 4.5 μM 2,4-D and 4.6 μM kinetin. Pieces of calli were subcultured on media with different concentrations and combinations of 2,4-D (1.0,2.5 and 5.0 μM) and kinetin (1.0, 5.0 and 25.0 μM), or without them. After six weeks, the relative increase of callus fresh weight, morphological and histological characteristics as well as the induction of adventitious shoots and roots were investigated. Histological analysis of callui from the 1st subculture showed that callus predominantly consisted of parenchymatous cells surrounded with peripheral meristematic regions. Tracheidal elements, individual and arranged in rows, were observed in all calli investigated. The best callus growth was achieved on media containing 2.5 μM 2,4-D alone or in combination with kinetin (1.0 and 5.0 pM). Addition of kinetin to the nutrient medium stimulated adventitious shoot induction. The shoot formation was improved in later subcultures. The highest number of shoots developed on media supplemented with 5.0 μM kinetin alone or in combination with 1.0 μM 2,4-D, as well as on media with 25.0 μM kinetin alone or in combination with 1.0 or 2.5 μM 2,4-D. The induction of adventitious roots was observed during all subcultures on all media tested

Differential esterase activity in leaves and roots of Centaurea ragusina L. as a consequence of salinity

Background and Purpose: Centaurea ragusina L. is an endemic Croatian plant species adapted to life in arid and salt-affected environments. Esterase activity (EST) and isoesterase patterns of C. ragusina plants cultured in vitro under saline and osmotic conditions were determined with an aim to evaluate the potential value of esterase activity as a biomarker of salt/osmotic stress as well as physiological significance of EST variations. Material and Methods: Rooted plantlets grown on MS ½ nutrient media supplemented with 150, 300, 450 or 600 mM NaCl or 300 mM mannitolwere investigated after 5, 10 and 15 days. Esterase activity was determined using either 1- or 2-naphthylacetate as substrates. Results and Conclusion: Esterase activities in shoots increased under low saline and mannitol treatments and decreased in response to increased saline treatments. The highest salt and concentration and mannitol stimulated EST activity in roots. In total, twelve and fourteen esterase isoenzymes were resolved in C. ragusina leaves and roots, respectively. Both salt and mannitol induced new esterase isoenzyme (EST11) while mannitol specifically induced two more (EST4-5); otherwise some bands were weakly expressed or even disappeared as a result of salinity in C. ragusina leaves. Two new isosterases (EST10-11) were resolved in mannitol- and salt-treated roots and four (EST2, EST12-14) only in salt-treated roots. Presented results demonstrate that esterase activities and their isoenzymic patterns could serve as useful bioindicators of salinity

Effects of osmotic stress on antioxidative system of duckweed (Lemna minor L)

Background and Purpose: It is known that osmotic stress may cause damage to cells by inducing active oxygen species production or by disrupting detoxification mechanisms. We hypothesize that increased activity of antioxidant enzymes in duckweed (Lemna minor L.) provides a mechanism of tolerance to osmotic stress. Material and Methods: Plants were subjected to NaCl- (50 mM), mannitol- (50 and 100 mM) and polyethylene glycol-mediated osmotic stress (PEG, 50 mM) for a period of 15 days. The responses of antioxidative system including also changes in growth, proline content and the extent of oxidative damage in terms of malondialdehyde, H2O2 and chlorophyll a to chlorophyll b (chl a/b) and chlorophyll a+b to carotenoids (chl a+b/car) ratios were studied. Results and Conclusion: Iso-osmolar concentrations of salt and mannitol significantly reduced relative growth rate compared to control plants while osmotic shockmediated by PEG caused complete cessation of growth. Proline content increased with the severity of osmotic stress showing the highest values in PEG-treated plants. The proline accumulation upon PEG stress was paralleled by equal increase of ascorbic acid pool. Catalase, ascorbate peroxidase and non-specific peroxidase activities showed considerable increase under all osmotic agents, especially PEG. The increased enzyme activities coincided with unchanged H2O2 levels, chl a/b and chl a+b/car under mannitol and salt stress. Despite the highest induction of antioxidative defense, a marked increase in lipid peroxidation and H2O2 level as well as decrease of chl a/b and chl a+b/car accompanied PEG treatment. These results suggested that induction of antioxidant defences is at least one component of the tolerance mechanism of plants to long-term osmotic stress

Rast i razvitak u kulturi hrastova lužnjaka (Quercus robur) i kitnjaka (Q. petraea) in vitro

Experiments were carried out to establish an initial culture of Quercus robur and Q. petraea. Apical and axillary buds, taken from seedlings and young plants (up to two years), were used as initial explants for the establishment of culture. The buds were satisfactorily disinfected by successive use of chlorine products and mercuric chloride. Three nutrient media were used: mod. De Fossard medium, ACM medium and mod. WPM medium. Various concentrations of hormones BA, KIN, 2iP, NAA, IBA and GA, were added to all media investigated. Elongation of cultured axillary and apical buds and in some cases adventitious bud induction were achieved when ACM and mod. WPM media were used. Age of explants used did not have an inhibitory effect on positive reaction obtained on both media.Istraženi su uvjeti za uspješno uvođenje eksplantata hrasta lužnjaka (Quercus robur) i kitnjaka (Q. petraea) u kulturi in vitro. Kao početni eksplantati korišteni su vršni i aksilarni pupovi klijanaca i mladih biljaka starih od 10 dana do dvije godine. Pupovi su uspješno sterilizirani klornim preparatom Izosan-G (l°/o) i živinim kloridom (1%). Ispitana je reakcija eksplantata na tri osnovne hranidbene podloge: mod. De Fossard, ACM i mod. WPM i nekoliko regulatora rastenja (BA, KIN, 2iP, NAA, IBA i GA,) u različitim koncentracijama i kombinacijama. Najpogodniji medij za produžni rast i normalni razvoj izdanaka bio je mod. WPM s 2,2 pM BA, 2,5 p,M IBA i 0,3 pM GA.,. Međutim, najveći postotak produljenih izdanaka dobiven je na mediju ACM uz dodatak BA (0,4—2,2 pM), KIN (0,4—0,9 pM), 2iP (0,5 pM) i NAA (0,05 pM). U kulturama je opaženo i zametanje adventivnih pupova na proksimalnoj strani eksplantata na sva tri ispitana medija. Kultura hrasta lužnjaka bila je uspješnija u odnosu na kulturu hrasta kitnjaka u većini usporednih pokusa