Isane Vera Karsburg

Identification of chromosomal deficiency by flow cytometry and cytogenetics in mutant tomato (Solanum lycopersicum, Solanaceae) plants

Structural chromosomal aberrations can occur spontaneously in plant karyotypes as a result of both intrinsic and extrinsic factors. These aberrations may affect sporophyte fitness because fundamental genes involved with distinct morphogenic process may be lost. Inadequate development of flowers and anomalous fruits without seeds has been observed in plants of Solanum lycopersicum L. (Solanaceae) ‘BHG 160’ of the tomato germplasm bank (Universidade Federal de Vicosa, Brazil). The nuclear DNA content, quantified by flow cytometry, showed that mutant ‘BHG 160’ possesses 0.09 pg (4.59%) less nuclear DNA content than does the wild-type ‘BGH 160’. Improved cytogenetical preparations evidenced that this difference was due to a spontaneous terminal deficiency in the short arm of the mutant ‘BGH 160’ Chromosome 1. These results suggest that the genes encoded in the short arm of Chromosome 1 may be involved in the development of flowers and fruits in the tomato.

Cytogenetic and identification of the nucleolus organizer region in Heliconia bihai (L.) L.

The genus Heliconia is not much studied and the number of existing species in this genus is still uncertain. It is known that this number relies between 150 to 250 species. In Brazil, about 40 species are native and known by many different names. The objective of this paper was to characterize morphometrically and to identify the NOR (active nucleolus organizer regions) by Ag-NOR banding of chromosomes of Heliconia bihai (L) L. Root meristems were submitted to blocking treatment in an amiprofos-methyl (APM) solution, fixed in methanol-acetic acid solution for 24 hours, at least. The meristems were washed in distilled water and submitted to enzymatic digestion with pectinase enzyme. The slides were prepared by dissociation of the root meristem, dried in the air and also on hot plate at 50°C. Subsequently, some slides were submitted to 5% Giemsa stain for karyotype construction and to a solution of silver nitrate (AgNO 3 ) 50% for Ag-NOR banding. The species H. bihai has 2n = 22 chromosomes, 4 pairs of submetacentric chromosomes and 7 pairs of metacentric chromosomes, and graded medium to short (3.96 to 0.67 μM), with the presence of active NOR in pairs 1 and 2 and interphase cells with 2 nucleoli. These are the features of a diploid species.

USO DO LICOR PIROLENHOSO NA PRODUÇÃO DE MUDAS IN VITRO E EX VITRO DE Oeceoclades maculata (Lindl). Lindl.

Pyroligneous fraction from wood carbonization can be used for several purposes. In this sense, this study aimed to test a pyroligneous liquor extracted during carbonization of forest residues for the vegetative development of the orchid Oeceoclades maculata. The concentrations of pyroligneous liquor used in the treatments were T1 = 0 mL L, T2 = 1 mL L, T3 = 2 mL L, T4 = 3 mL L, T5 = 4 mL L, and T6 = 5 mL L. These treatments were tested together with and without activated charcoal for in vitro and ex vitro propagation. In vitro developed protocorms were assessed according to development or not, the presence of fungus, leaves, and roots. For ex vitro evaluations, leaf size, size, the number of roots, total plant height, and the number of buds were assessed. Possible differences between treatments were tested by means of analysis of variance (ANOVA) and Tukey’s test at 5% significance. The use of pyroligneous liquor at low doses was significant in vegetative tissue development as well as for root and leaf formations in O. maculata seedlings since it presents all the essential mineral elements to the structural development of these plants.

INDUÇÃO E IDENTIFICACAO DE POLIPLOIDIA EM Hymenaea courbaril L. var.stilbocarpa(Hayne) Lee et Lang

The Hymenaea courbaril var. stilbocarpa wood has a high density being employed in construction, carpentry and laminate. The stem exudes a rich terpene resin which can be used in the varnish industry. The endocarp of the fruit is edible and can be eaten raw. The chromosomal duplication of forest species aims to maximize economic interest features, such as those related to the development and forest gain. This study aimed to induce and verify polyploidy in root meristem cells of Hymenaea courbaril through morphological and cytological features. To induce polyploidy, the root meristems were exposed to the trifluralin herbicide at a concentration of 3 mM at 4 oC for 14 (control), 24, 48, 72 and 96 h. Then, the rootlets were stored for 24 h in a closed flask and refrigerated in methanol: acetic acid solution (high purity) in the ratio 3:1, at -4 oC. Root meristems were digested in pectinase enzyme (Sigma TM ). Mitotic cells were obtained by cell dissociation, air drying and hotplate. 30 cells in metaphase were colored with Giemsa 5% and analyzed. The stomata were obtained from young plantlets of each treatment under the same physical and chemical conditions. For stomata analysis, was used epidermal print of adaxial leaf, with universal instant adhesive (Super Bonder TM ). 200 stomata were analyzed of each treatment. Among the four treatments evaluated, the exposure of root meristem for 96 h in 3 mM trifluralin, at 4 oC, induced genome duplication in Hymenaea courbaril L. var. stilbocarpa with 2n = 4x = 48 chromosomes and stomata average size of 0.215 mm, being superior to the other treatments.

Cytogenetic characterization of Encyclia caximboensis cultivated in vitro (Orchidaceae).

Encyclia caximboensis is an Amazonian species endemic to the Serra do Cachimbo, which is located between the northern of the Mato Grosso state and the southern part of Para state. Studies reporting in vitro cultivation and cytogenetic characterization of this species are still scarce. Therefore, the objective of this work was to determine the cytogenetic characteristics and to identify the nucleolar organizer regions (NORs) of the species E. Caximboensis, cultivated in vitro. Seeds of E. caximboensis were disinfected using a syringe and subsequently cultivated in MS medium without growth regulators. The germination started after 20 days of culture, with the development of protocorm and 40,500 seedlings were obtained after 90 days of culture. To perform the cytogenetic solution, 3:1 (v/v) and the slides were stained using 5% Giemsa solution. Ag-NOR banding was carried out on 20-day-old slides by incubation in 50% silver nitrate solution (AgNO3 ) for 19 hours. The results indicated that E. caximboensis has 2n=2x=24 with all metacentric type chromosomes, ranging from 1.88 to 0.66 µm in length, with simple NORs in small blocks localized in the proximal region of the third chromosome pair