No abstract

ResumoA fotossíntese é um processo complexo que envolve a realização de várias reações que, muitas vezes, tornam este conteúdo de difícil compreensão para os alunos. Neste trabalho, objetivou-se investigar se um modelo didático interativo, confeccionado com materiais simples, poderia facilitar a compreensão e aprendizado dos alunos referente ao tema fotossíntese. Para tanto, inicialmente foi solicitado aos alunos de uma turma do 1º ano do Ensino Médio de um colégio público estadual do oeste do Paraná que esquematizassem o que sabiam sobre fotossíntese e respondessem a um questionário. Verificou-se que muitas das concepções prévias dos alunos traziam conceitos generalistas ou errôneos, como a ideia de que a fotossíntese é o processo de respiração das plantas, e que o O2 é oriundo do CO2, e não da foto-oxidação da água. Estas concepções foram importantes para planejar a abordagem do tema, que foi realizada de forma expositiva e dialogada, utilizando um modelo didático interativo para evidenciar as explicações, e em seguida, um novo questionário foi respondido pelos alunos. Concluiu-se que o uso do modelo didático interativo foi eficiente, pois ajudou a consolidar conceitos corretos, ao mesmo tempo em que introduziu novos conceitos e abalou as relações equivocadas.Palavras-chave: Ensino de Ciências e Biologia, Energia Solar, Clorofila. AbstractPhotosynthesis is a complex process that involves the implementation of several reactions which, many times, makes this content difficult for students to understand. The objective of this study was to investigate if an interactive didactic model, crafted with simple materials, could facilitate the understanding and learning of students on photosynthesis. Initially students of first year high school class from a public school Western of Paraná were asked to diagram what they knew about photosynthesis and respond to a questionnaire. It was concluded that many of the students' prior concepts were general or inaccurate, such as the idea of photosynthesis being the process of respiration in plants, and O2 coming from the CO2, not from the photooxidation of water. These prior conceptions were important for planning the approach to the subject. The process of photosynthesis was then covered in lecture and dialogued, using the interactive didactic model to highlight the explanations. A new questionnaire was completed by the students, and concluded that the use of the interactive didactic model was efficient, since it helped to consolidate correct concepts and simultaneously, introduced new ones as well it shook the equivocal relations.

Asteraceae is the largest family of angiosperms and occurs predominantly in grassland areas. This study aimed to identify and characterize the foliar trichomes of 34 Asteraceae species from Sand-fields of the Pampa biome, by means of epidermal analyzes (front and transverse view) under light and scanning electron microscopy. Eleven types of trichomes were identified and characterized: three glandular (recurved on the epidermis, erect-capitate and uniseriate to multiseriate vesicular-capitate) and eight non-glandular (simple conical, flagellate-filiform, aseptate-flagellate, whip-like, oblique-flagellate, branched with one arm, branched with two T-shaped arms, branched with three or more arms). The most representative glandular type was the uniseriate to multiseriate vesicular-capitate (58%) and the non-glandular type was the simple conical (35%). A large number of trichomes is an adaptive strategy to the adverse conditions of the Pampa biome and its morphological diversity can be useful in the family systematics.

Cyperaceae is the third largest family among the monocotyledons and is highly represented in grassland environments. The aim of the present study was to conduct a floristic inventory of Cyperaceae in the grasslands of Guartelá State Park (GSP) and to elaborate keys to identify the species, the first for this family in this vegetation type in Paraná state. The GSP is home to relictual vegetation in Paraná, where grassland phytophysiognomies predominate, especially in open areas and rocky outcrops. The inventory was based on field collections and database searches. The family Cyperaceae is represented in the GSP by 32 taxa belonging to seven genera, with Rhynchospora (11 spp.), Bulbostylis (8 spp.), and Cyperus (7 spp.) being the genera with the greatest richness. It should be noted that all the species are native and two are endemic to Brazil. Species occurrence was recorded both in drylands and wetlands environments, emphasizing the importance of microenvironmental conservation in the park. The main literature sources for each genus, as well as information regarding distribution and habitat, are here provided.

In Brazil, grassland ecosystems of the Pampa are restricted to Rio Grande do Sul State (RS) and constitute the largest temperate natural grassland in the world. There are no recent data to indicate how much of these fields was lost in the state, but excursions made in recent years have pointed to a high conversion of native fields into crops. This situation has alerted to the intensification of biodiversity loss and the biological impoverishment of these fields. In view of the above, this study characterizes plant diversity in fields of the southern and western portion of RS. The study was based on publications of recent years that indicate the problems that effectively threaten this diversity. Pampa fields are natural and have a great diversity, constituting a considerable genetic heritage, ensuring the provision of ecosystem services to human populations. The few bioprospecting studies on species from these fields suggest that much remains to be discovered and that actions need to be taken to inhibit field destruction. These fields have never been treated as priority areas for conservation, but it is our commitment to reverse this transformation and destruction.