Elizabeth Orika Ono

Application of brassinosteroid to Tabebuia alba (Bignoniaceae) plants

The objective of this study was to observe the effects of brassinosteroid, gibberelin, and auxin application on the development and foliar anatomy of Tabebuia alba (Cham.) Sandw. seedlings. T. alba seedlings were grown in plastic bags with fertilized soil and treated with the following: 1- water (control); 2- brassinolide (BR1) 0.104 mM; 3- BR1 0.208 mM; 4- 3-indoleacetic acid (IAA) 0.2854 mM; 5- IAA 0.5708 mM; 6- GA3 (gibberellin A3) 0.1443 mM; 7- GA3 0.2887 mM; 8- GA3 0.072 mM + IAA 0.1427 mM; 9- GA3 0.1443 mM + IAA 0.2854 mM; 10- GA3 0.072 mM + BR1 0.052 mM; and 11- GA3 0.1443 mM + BR1 0.104 mM. Plant height and petiole length were measured before the treatments and 21 days after application of the growth regulators. These data allowed the calculation of stem and petiole growth rates. The results showed that GA3 + brassinolide produced the highest stem and petiole growth rates and brassinolide application stimulated petiole growth but not stem growth. The anatomical study of leaves showed alterations in blade and petiole thickness, palisade and spongy parenchyma height, and epidermis cells.

Enraizamento de estacas de brotações oriundas de estacas radiculares de amoreira-preta¹

Este trabalho objetivou verificar o efeito do acido indol-3-butirico (IBA) na promocao do enraizamento de brotacoes oriundas de estacas radiculares de amoreira-preta. O experimento foi conduzido de junho a agosto de 2010, na UNESP de Botucatu - SP, sendo o delineamento em blocos casualizados, com seis concentracoes de IBA e seis repeticoes, com a parcela constituida por 12 brotacoes. Os tratamentos constaram de seis concentracoes de IBA, na forma de solucao: T1= 0 mg L-1; T2= 250 mg L-1; T3 = 500 mg L-1; T4= 1.000 mg L-1; T5= 2.000 mg L-1 e T6= 4.000 mg L-1 aplicados na base das brotacoes, durante dez segundos. Apos 60 dias, foram avaliados a: porcentagem de enraizamento, massa fresca de raiz, massa seca de raiz, comprimento da maior raiz e porcentagem de sobrevivencia das brotacoes. A concentracao de 250 mg L-1 de IBA favoreceu a massa fresca e seca de raizes oriundas de estacas radiculares de amoreira-preta. As maiores concentracoes de IBA inibiram o enraizamento das estacas de brotacoes.

Indole Butyric and Boric Acids in the Rooting of Atemoya “Thompson” Stem Cuttings

The current study aimed to evaluate the effect of indole butyric acid (IBA) and boric acid to induce rooting on atemoya “Thompson” cuttings. A randomized block design with 10 treatments and four blocks was laid out. The treatments consisted in the use of different levels of IBA (i.e., 0, 500, 1,000, 2,000 and 4,000 mg/L) with or without boric acid at 150 mg/L. The cuttings were placed to root in expanded polystyrene (EPS) trays with 72 cells and kept in a greenhouse under misting. At 120 d after planting, leaf dry and fresh masses (g), root dry and fresh masses (g), percentage of rooting, live cuttings (LC), live cuttings with callus (LCC), number of roots per cuttings and number of emitted leaves (NEL) were evaluated. Data were submitted to analysis of variance and comparison of means by Tukey test at 5% probability. Results indicated no statistically significant differences in both application methods (separate or associated with boric acid) for all evaluated variables, except for LC, in which boric acid provided higher survival rates. It could be concluded that the propagation method using either separate IBA application or associated with boric acid is unsuitable to induce rooting on atemoya “Thompson” cuttings.

Mensageiros secundários relacionados à ação dos hormônios vegetais

Os conhecimentos atuais sobre os mecanismos de acao dos hormonios vegetais sao ainda fragmentados e incompletos. No entanto, ja se sabe que a acao reguladora e que o potencial de amplificacao de sinais destas moleculas se da atraves de vias de traducao de sinais iniciadas a partir da ligacao dos hormonios aos seus receptores. A formacao de mensageiros secundarios de vida curta ocorre em funcao do inicio de uma cadeia de eventos resultante da ligacao do hormonio vegetal ao seu receptor. Existem varios mensageiros secundarios, mas cada hormonio, atuando num tipo celular especifico, desencadeia o surgimento de mensageiros secundarios tambem especificos. Estes mensageiros secundarios incluem o 1,2-diacilglicerol, o inositol 1, 4,5-trifosfato e os ions calcio, entre outros. Palavras-chave: transducao de sinais; 1,2-diacilglicerol; inositol 1, 4,5-trifosfato, calmodulina, calcio. ABSTRACT The current knowledge about the mechanisms of action of plant hormones is still fragmented and incomplete. However, it’s known that the regulatory action and that the potential of signal amplification of these molecules occurs through the process of translation of signals initiated from the binding of hormones to their receptors. The formation of short life secondary messengers occurs due to the start of a chain of events resulting from the binding of plant hormone to its receptor. There are several secondary messengers, but each hormone, acting in a specific cell type triggers the appearance of secondary messengers, also specific. These second messengers include 1,2-diacylglycerol, inositol 1,4,5-triphosphate and calcium ions, among others. Key words: signal transduction; 1,2-diacylglycerol; inositol 1,4,5-triphosphate, calmodulin, calcium .