A construção do habitus institucional: história do Instituto de Química da UNESP/Araraquara.

Apresentamos neste texto as principais fases de desenvolvimento do Instituto de Química da UNESP/Araraquara, cuja trajetória tem início com a proposta de atendimento à demanda por formação de professores de química. Ao longo de 50 anos de história a Instituição enfrentou diversos desafios por meio de estratégias que revelam seu habitus. Eles contribuíram para a institucionalização e consolidação de um grande centro de pesquisa, ensino e extensão, embora a formação de professores e a pesquisa em Ensino de Ciências nem sempre tenha encontrado espaço para se desenvolver plenamente. Além de analisar em detalhes o desenvolvimento de uma grande Instituição nossa pesquisa aponta para possibilidades futuras.

A light in the shadow: the use of Lucifer Yellow technique to demonstrate nectar reabsorption

Abstract Background Nectar reabsorption is a widely known phenomenon, related to the strategy of resource-recovery and also to maintain the nectar homeostasis at the nectary. The method currently performed to demonstrate nectar being reabsorbed involves the use of radioactive tracers applied to the nectary. Although this method works perfectly, it is complex and requires specific supplies and equipment. Therefore, here we propose an efficient method to obtain a visual demonstration of nectar reabsorption, adapting the use of Lucifer Yellow CH (LYCH), a fluorescent membrane-impermeable dye that can enter the vacuole by endocytosis. Results We applied a LYCH solution to the floral nectary (FN) of Cucurbita pepo L., which is a species known for its ability of nectar reabsorption, and to the extrafloral nectary (EFN) of Passiflora edulis Sims which does not reabsorb the secreted nectar. In all tests performed, we observed that LYCH stained the nectary tissues differentially according to the reabsorption ability of the nectary. The treated FN of C. pepo presented a concentrated fluorescence at the epidermis that decreased at the deeper nectary parenchyma, until reaching the vascular bundles, indicating nectar reabsorption in the flowers of the species. In contrast, treated EFN of P. edulis presented fluorescence only at the cuticle surface, indicating that nectar is not reabsorbed by that particular tissue. Conclusion LYCH is an efficient marker to demonstrate nectar reabsorption.