Browsing by Author "Pasqual, Moacir"

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    Dendrobium nobile in vitro flowering induction
    (2023-05-22) Nadal, Michele Carla; Silva Andrade, Gracielle Vidal; Nunes Flores, José Henrique; dos Reis, Michele Valquíria; Rodrigues, Vantuil Antonio; Pasqual, Moacir
    In vitro flowering is a technique used in genetic improvement that accelerates generations and favors the faster fixation of new traits of agronomic and market interest. The study aimed to establish a protocol for the in vitro flowering of Dendrobium nobile, through the combined temperature and of the growth regulator thidiazuron (TDZ) effects. Experiments was performed in a flask that was kept in a BOD incubator at 18, 21, or 24 °C or in a growth room at 26 °C. The TDZ concentrations were 0.0, 0.5, 1.0, and 2.0 mg L-1. The highest percentage of flowering shoots of 13.7% occurred at a concentration of 2 mg L-1 of TDZ grown at a temperature of 18 °C. Dendrobium nobile in vitro flowering was promoted in plants cultivated in ½ MS supplemented with 30 g L-1 sucrose, 5.5 g L-1 agar, 100 mL L-1 coconut water, pH 6.0, and 2.0 mg L-1 TDZ at a controlled temperature of 18 °C and a photoperiod of 16 h. The in vitro flowering induction protocol of the D. nobile species could be used or improved for future studies.Keywords: flowering, temperature, thidiazuron, Orchidaceae.
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    Impact of monochromatic lights on the in vitro development of Cattleya walkeriana and effects on acclimatization
    (2023-06-03) Nadal, Michele Carla; Bernardes Machado, Natalia; dos Santos, Cyntia Stephânia; Nunes Flores, José Henrique; Dória, Joyce; Pasqual, Moacir
    Light quality is an important factor for the adequacy of plant production through plant tissue culture, as it directly interferes with morphogenesis and photosynthetic capacity of explants. The objective of this study was to analyze the impact of monochromatic lights such as light emitting diode (LED) on the in vitro development of Cattleya walkeriana G. and their effects on acclimatization. The plants were developed in vitro under the colors of green, blue, yellow, red, 2 red:1 blue, and white LED lights. For in vitro cultivation, Knudson medium was used, supplemented with 20 mg L-1 sucrose, 5.5 mg L-1 agar, 2% activated charcoal, 100 mL coconut water, and pH 6.0. For ex vitro cultivation, the plants were acclimatized in styrofoam trays containing sphagnum as a substrate. In general, the supplied light lengths impactedin vitro growth and acclimatization analyses. There was influence on the cuticle thickness of plants in vitro. Chlorophyll and carotenoid contents were not significant. We can conclude that light lengths formed by 2 red:1 blue, red and yellow LEDs can be indicated for better performance in the production of C. walkeriana. The 2 red:1 blue and red LEDs provide superior in vitro development than the others, with gains for the species in acclimatization. The yellow LED provided a possible in vitro hardening, which ensured the greatest success of the seedlings during acclimatization.
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    Protocol for in vitro rooting of Pyrus comunnis rootstocks
    (2023-04-15) Nadal, Michele Carla; Bernardes Machado, Otávio; Araújo, Ronilson Carlos; Rodrigues, Filipe Almendagna; Rufato, Leo; Dória, Joyce; Pasqual, Moacir
    Effective protocols for in vitro rooting for woody fruit trees are still a challenge for in vitro seedling production, especially when there is a need to insert new cultivars or rootstocks. These protocols are essential to accelerate studies in plant breeding programs and for seedling distribution. This study evaluated the use of 6-Benzylaminopurine (IBA) in in vitro rooting of Pyruscomunnis rootstocks, clones ‘OHxF87’ and Pyrodwarf. Explant exposure times (0, 24, 48, 72, and 96 hours) to 20 mg L-1 IBA were tested for in vitro rooting. The exposure to IBA resulted in rooting rates above 80%, surpassing some results reported in the literature. The 24-hour treatment provided 81,81% survival, leading to an average growth of five roots with 19 mm length, for ‘OHxF87’ rootstock. The same exposure time resulted in the highest survival rate (75%) and the highest mean root number, seven roots per plant with 10 mm length, for ‘PDW’ rootstock. Root formation did not occur in the absence of synthetic auxin. Therefore, it can be concluded that a 24-hour exposure at 20 mg L-1 IBA was sufficient to promote in vitro rooting in ‘OHxF87’ and Pyrodwarf rootstocks’.