Detection of cytokinins and auxin in plant tissues using histochemistry and immunocytochemistry.

We report a new method for histochemical localization of cytokinins (CKs) in plant tissues based on bromophenol blue/silver nitrate staining. The method was validated by immunohistochemistry using anti-trans-zeatin riboside antibody. Indole-3-acetic acid (auxin, IAA) was localized by anti-IAA antibody in plant tissues as a proof for IAA histolocalization. We used root sections, because they are major sites of CKs synthesis, and insect galls of Piptadenia gonoacantha that accumulate IAA. Immunostaining confirmed the presence of zeatin and sites of accumulation of IAA indicated by histochemistry. The colors developed by histochemical reactions in free-hand sections of plant tissues were similar to those obtained by thin layer chromatography (TLC), which reinforced the reactive sites of zeatin. The histochemical method for detecting CKs is useful for galls and roots, whereas IAA detection is more efficient for gall tissues. Therefore, galls constitute a useful model for validating histochemical techniques due to their rapid cell cycles and relatively high accumulation of plant hormones.

Micropropagation of Agapanthus umbellatus var. minor by using two systems of multiplication / Micropropagação de Agapanthus umbellatus var. minor com dois sistemas de multiplicação

For conventional micropropagation methods, semisolidified medium (SM) is used; the use of this medium requires intense manipulation of the cultures and skilled labor. Systems that use liquid medium show equal or better efficiency of the multiplication process, besides reducing the cost for the elimination of agar. In this study, we evaluated the mass propagation of Agapanthus umbellatus var. minor two in vitro multiplication systems (SM system and temporary immersion system [SIT]). The plant material was grown in MS medium supplemented with 6-benzylaminopurine (6-BA; 0.0, 8.9, 17.8, and 35.6 ?M). The data obtained in this study demonstrate that the two systems used were efficient for the multiplication phase of this species. However, we recommend SIT in view of its reuse in the process of multiplication and rooting. Moreover, simple construction, low cost of the culture medium, and low cost of the bioreactors and the fact that agar is not required qualify this system as an efficient alternative for large-scale micropropagation of Agapanthus umbellatus var. minor. We recommend 17.8 ?M 6-BA for the SM system and 8.9 ?M 6-BA for SIT.

Na metodologia convencional de micropropagação utiliza-se meio nutritivo geleificado, o que acarreta intensa manipulação das culturas e envolve mão-de-obra especializada. Porém, há uma tendência em se utilizar biorreatores em meio líquido com igual ou até melhor eficiência do processo de multiplicação, além de diminuir o custo pela eliminação do ágar. O presente trabalho teve como objetivo comparar a eficiência do uso do meio geleificado (MG) e de biorreator de imersão temporária (BIT), visando a propagação em massa de Agapanthus umbellatus var. minor. O material vegetal cresceu em meio MS suplementado com diferentes concentrações de 6-BAP (0,0; 8,9; 17,8 e 35,6 ?M). As avaliações de crescimento e desenvolvimento aos 60 dias mostraram que ambos os sistemas foram eficientes na fase de multiplicação. No entanto, a imersão temporária pode ser recomendada, com vista à sua reutilização no processo de multiplicação e enraizamento. Além disso, sugere-se este sistema como uma alternativa eficiente para a micropropagação em larga escala desta espécie por sua simplicidade na construção, custo mais baixo do meio de cultura, por não utilizar ágar e pelo baixo custo dos biorreatores. Dentre as concentrações utilizadas nos sistemas, recomenda-se a concentração de 17,8 ?M de 6-BAP para o MG e 8,9 ?M de 6-BAP para o BIT.

Micropropagation of Agapanthus umbellatus var. minor by using two systems of multiplication / Micropropagação de Agapanthus umbellatus var. minor com dois sistemas de multiplicação

For conventional micropropagation methods, semisolidified medium (SM) is used; the use of this medium requires intense manipulation of the cultures and skilled labor. Systems that use liquid medium show equal or better efficiency of the multiplication process, besides reducing the cost for the elimination of agar. In this study, we evaluated the mass propagation of Agapanthus umbellatus var. minor two in vitro multiplication systems (SM system and temporary immersion system [SIT]). The plant material was grown in MS medium supplemented with 6-benzylaminopurine (6-BA; 0.0, 8.9, 17.8, and 35.6 ?M). The data obtained in this study demonstrate that the two systems used were efficient for the multiplication phase of this species. However, we recommend SIT in view of its reuse in the process of multiplication and rooting. Moreover, simple construction, low cost of the culture medium, and low cost of the bioreactors and the fact that agar is not required qualify this system as an efficient alternative for large-scale micropropagation of Agapanthus umbellatus var. minor. We recommend 17.8 ?M 6-BA for the SM system and 8.9 ?M 6-BA for SIT.(AU)

Na metodologia convencional de micropropagação utiliza-se meio nutritivo geleificado, o que acarreta intensa manipulação das culturas e envolve mão-de-obra especializada. Porém, há uma tendência em se utilizar biorreatores em meio líquido com igual ou até melhor eficiência do processo de multiplicação, além de diminuir o custo pela eliminação do ágar. O presente trabalho teve como objetivo comparar a eficiência do uso do meio geleificado (MG) e de biorreator de imersão temporária (BIT), visando a propagação em massa de Agapanthus umbellatus var. minor. O material vegetal cresceu em meio MS suplementado com diferentes concentrações de 6-BAP (0,0; 8,9; 17,8 e 35,6 ?M). As avaliações de crescimento e desenvolvimento aos 60 dias mostraram que ambos os sistemas foram eficientes na fase de multiplicação. No entanto, a imersão temporária pode ser recomendada, com vista à sua reutilização no processo de multiplicação e enraizamento. Além disso, sugere-se este sistema como uma alternativa eficiente para a micropropagação em larga escala desta espécie por sua simplicidade na construção, custo mais baixo do meio de cultura, por não utilizar ágar e pelo baixo custo dos biorreatores. Dentre as concentrações utilizadas nos sistemas, recomenda-se a concentração de 17,8 ?M de 6-BAP para o MG e 8,9 ?M de 6-BAP para o BIT.(AU)

2D autocorrelation modelling of the inhibitory activity of cytokinin-derived cyclin-dependent kinase inhibitors.

The inhibitory activity towards p34(cdc2)/cyclin b kinase (CBK) enzyme of 30 cytokinin-derived compounds has been successfully modelled using 2D spatial autocorrelation vectors. Predictive linear and non-linear models were obtained by forward stepwise multi-linear regression analysis (MRA) and artificial neural network (ANN) approaches respectively. A variable selection routine that selected relevant non-linear information from the data set was employed prior to networks training. The best ANN with three input variables was able to explain about 87% data variance in comparison with 80% by the linear equation using the same number of descriptors. Similarly, the neural network had higher predictive power. The MRA model showed a linear dependence between the inhibitory activities and the spatial distributions of masses, electronegativities and van der Waals volumes on the inhibitors molecules. Meanwhile, ANN model evidenced the occurrence of non-linear relationships between the inhibitory activity and the mass distribution at different topological distance on the cytokinin-derived compounds. Furthermore, inhibitors were well distributed regarding its activity levels in a Kohonen self-organizing map (SOM) built using the input variables of the best neural network.