Raírys Cravo Herrera

Micropropagation of Maclura tinctoria L.: an endangered woody species

Algumas especies nativas produzem sementes com baixa porcentagem de germinacao e, na maioria dos casos, dormencia que pode dificultar o aparecimento de novos individuos, por meio da propagacao sexuada. A Maclura tinctoria tem sido considerada como ameacada de extincao devido ao uso indiscriminado de sua madeira e a baixa taxa de germinacao de suas sementes. Nesse contexto, o objetivo deste estudo foi estabelecer uma metodologia de propagacao in vitro para a especie. Combinacoes de ANA + BAP, diferentes concentracoes de GA3 e combinacoes de AIB + carvao ativado foram avaliadas na inducao de brotacoes, alongamento caulinar e inducao de enraizamento, respectivamente. Os resultados indicaram que a maxima formacao de brotacoes foi obtida quando 5,37 mM NAA + 4,45 mM BAP foram utilizados. O crescimento das brotacoes foi observado com 5,48 mM GA3. Para a formacao de raizes, foi indicado o uso do meio WPM, com pH ajustado para 7,0, suplementado com 23,62 mM AIB e 4,7 g L-1 de carvao ativado. O uso de sombrite 70% por sete dias, seguido da utilizacao de sombrite 50 e 30%, tambem por sete dias cada, promoveu 97% de sobrevivencia de plantas.

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.

Indução, análises morfológicas e ultraestruturais de calos de maracujazeiro nativo

Analysis of calluses with embryogenic characteristics is important for subsequent in vitro regeneration of species with desirable agronomic traits such as the Passiflora gibertii native passion fruit. In this context, the present study aimed to analyze the induction of calluses from leaf explants of Passiflora gibertii N. E. Brown, as well as their morphologic and ultra-structural characterization. Cotyledonary leaves were inoculated in culture medium containing 2,4-D and picloram in association with kinetin. After 30 days of cultivation in the dark, the obtained calluses were prepared for the visualization in electron microscope (transmission and scanning) and light microscope. The results allowed to infer that the addition of picloram and kinetin to the culture medium promotes higher callus formation in cotyledonary leaf explants of P. gibertii than 2,4-D and kinetin. The growth regulator 2,4-D provides the formation of calluses with small isodiametric cells and small intercellular spaces, an organized cellular system and the predominance of round shaped mitochondria. Predominance of large and elongated cells with intercellular spaces, a non-organized cellular system and predominance of elongated mitochondria was observed when picloram was used.