Jorge Marcelo Padovani Porto

Qualidade de luz no cultivo in vitro de Dendranthema grandiflorum cv. Rage: características morfofisiológicas

In micropropagation, the maintenance of the growth rooms is labor-consuming and expensive, which increases the necessity of studies involving the manipulation and control of the culture conditions to optimize the in vitro growth. The quality of light may modify the morphogenesis of the plants through many processes mediated by receivers, which absorb the light in the blue and red region of the spectrum, being therefore, a viable way to increase the quality of the micropopagated plants. This work aimed at evaluating the effect of the spectral alteration under conditions of natural light on the morphophysiology of micropropagated chrysanthemum [Dendranthema grandiflorum (Ramat.) Kitam] plants. Nodal segments with one bud cultivated in vitro were used as explants. The medium used was MS with half of its salts concentration supplemented with 15g.L-1 sucrose. The incubation conditions were growth room (GR), this being the control treatment, greenhouse (GH) without shadow protection and greenhouse with 50% shadow in the colors black, blue, and red. The evaluation was done 60 days after the implantation of the assay. For the leaf number, GR showed to be the most effective incubation form, with a higher number of leafs. The same occurred with the number of roots and shoots and the average length of roots. For the aerial part length, GR and GH with shadow protection in all three colors were more efficient. Considering the anatomical aspects for stomatal density, a greater number of stomatal/mm2 was observed in GH without shadow protection and in GH with red shadow protection. For the polar and equatorial diameters of the stomata, GR without shadow protection, followed by GR with shadow protection in the colors blue and red, presented a bigger stomatal diameter. With the presented results, it is possible to recommend the use of natural light for the in vitro cultivation of chrysanthemum, however, the manipulation of the spectral quality is not recommended.

Induction and Morpho-Ultrastructural Analysis of Organogenic Calli of a Wild Passionfruit

This work studied a new protocol for organogenic ca lli induction and characterization of the morpholog y and ultrastructure of callogenesis in leaf explants of Passiflora gibertii N. E. Brown , a native passion fruit species from Brazil. Calli induction was performed in different growth conditions (light and dark), different MS me dium salt concentrations (MS and MS half strength) and the pr esence or absence of coconut water. The leaf explan ts maintained in the dark were more responsive to bud formation. In order to reduce spending on in vitro culture, the most suitable induction medium for P. gibertii organogenesis could, therefore be the MS half stre ngth salt concentration medium maintained in the dark. The ad dition of coconut water to the culture medium was e ssential for both calli induction and bud formation. The mor phological and ultrastructural features of the orga nogenic calli were isodiametric cells, characterized by an organi zed cellular system, nucleus with prominent nucleol i, presence of starch grains and dense cytoplasm rich in endoplasm ic reticulum. The scanning electron microscopy demo nstrated that buds were present on these calli.

In vitro Plantlets Regeneration from Nodal Segments of Murici (Byrsonima gardneriana)

This study aimed to develop efficient protocols for the in vitro micropropagation of Byrsonima gardneriana . Nodal segments were obtained from seedlings germinated in vitro with 60 days of life. These were inoculated in MS/2 supplemented with 87.64 µM of sucrose and solidified with 0.7% of agar, supplemented with different concentrations of cytokinin 6-benzylaminopurine (0.0; 2.0; 4.0 and 8.0 µM) associated with different concentrations of auxin, indole acetic acid (0.0; 0.5 and 1.0 µM) and naphthaleneacetic acid (0.0; 0.5 and 1.0 µM). The sprouting were individualized and transferred to MS/2 cultures with different concentrations of indole butyric acid (0.0; 1.0; 2.0 and 3.0 µM), and presence and absence of activated charcoal (1.0 g L -1 ). The use of concentrations from 2.0 to 4.0 µM 6-benzylaminopurine was efficient in the multiplication of B. gardneriana , given that, using concentrations above these, a decrease in this efficiency occurs. The use of auxin interfered negatively with the results. In vitro rooting occurs even in medium free of auxin. The activated charcoal was insufficient for rooting. The use of growth regulators 6-benzylaminopurine and indole butyric acid are efficient in micropropagation of B. gardneriana , however, further studies should be performed to optimize this protocol.

Pre-germination Treatments, Quality of Light and Temperature on Syagrus coronata (Mart.) Becc. Seeds Germination

Studies show that most species of palm trees present seed dormancy. This characteristic hinders the production of seedlings, due to the long period for germination and the unevenness of the seedlings. The specie Syagrus coronata , despite being widely used as food and economic resources, presents also seed dormancy, which hinders its propagation. Thus, this work aimed at evaluating the germination of S. coronata seeds using different methods of dormancy breaking and also, under different qualities of light and temperature. To do so, the seed endocarps were scarified by friction, puncture and complete removal of the endocarp, and the pre-soaking of seeds at different concentrations (50, 100, 200 and 400 mg L -1 ) of gibberellic acid (GA 3 ) and indolebutyric acid (IBA). We also evaluated the effect of germination in seeds exposed to different conditions of light (white, red, far red, blue and dark) and to different temperatures (25, 30, 35 and 20-30 °C). The data show that the act of rubbing the endocarp optimizes the seed germination process. Solutions containing growth regulators in the pre-soaking of seeds have a negative impact on germination. And the absence of light and the constant temperature of 25 °C are the most suitable for germination. The results indicate that S. coronata seeds have physical dormancy, and, despite obtaining greater germination in the dark, they are neutral photoblastic.