Convergence Of A Specialized Root Trait In Plants From Nutrient-impoverished Soils: Phosphorus-acquisition Strategy In A Nonmycorrhizal Cactus.

In old, phosphorus (P)-impoverished habitats, root specializations such as cluster roots efficiently mobilize and acquire P by releasing large amounts of carboxylates in the rhizosphere. These specialized roots are rarely mycorrhizal. We investigated whether Discocactus placentiformis (Cactaceae), a common species in nutrient-poor campos rupestres over white sands, operates in the same way as other root specializations. Discocactus placentiformis showed no mycorrhizal colonization, but exhibited a sand-binding root specialization with rhizosheath formation. We first provide circumstantial evidence for carboxylate exudation in field material, based on its very high shoot manganese (Mn) concentrations, and then firm evidence, based on exudate analysis. We identified predominantly oxalic acid, but also malic, citric, lactic, succinic, fumaric, and malonic acids. When grown in nutrient solution with P concentrations ranging from 0 to 100 μM, we observed an increase in total carboxylate exudation with decreasing P supply, showing that P deficiency stimulated carboxylate release. Additionally, we tested P solubilization by citric, malic and oxalic acids, and found that they solubilized P from the strongly P-sorbing soil in its native habitat, when the acids were added in combination and in relatively low concentrations. We conclude that the sand-binding root specialization in this nonmycorrhizal cactus functions similar to that of cluster roots, which efficiently enhance P acquisition in other habitats with very low P availability.

Comparação entre métodos para mensuração da potência aeróbia em atletas tetraplégicos= : Comparison of methods for aerobic power assessment in athletes with tetraplegia

Universidade Estadual de Campinas . Faculdade de Educação Física

Estrutura de um curso de taxonomia de campo: o modelo aplicado em Ubatuba, São Paulo

The field activities are essential for the education of a good taxonomist. The most common problems found in field activities are: a) large number of students, b) heterogeneous educational background and unlevelled knowledge of the participants, c) repetitions and tendency of collecting the more evidents life-forms. The causes and consequences of such problems are discussed herein. The proposed solution is a methodology, based on many years of experience in field courses for undergraduate and graduate courses. Topics about the ideal number of participants, area of coverage, period of activity, division of work and the necessary material and equipment are discussed. According to the number of species collected at the same place, this methodology may result in a list of local species with precise information about the life-forms, habitat, common names, frequency, uses, phenology and further information in this kind of work. The results of the aplication of this metodology in a field course held in the region of Ubatuba-SP are presented.

História do lazer na natureza no Rio de Janeiro entre 1779 e 1838 : um estudo de caso

Universidade Estadual de Campinas . Faculdade de Educação Física

O brincar no contexto escolar : significados das brincadeiras realizadas em aulas de educação física e no recreio

Universidade Estadual de Campinas . Faculdade de Educação Física

Uma analise das alterações nas variáveis fisiológicas e aptidão física (teste da FIFA) e suas prováveis interferências no desempenho do arbitro durante a partida

Universidade Estadual de Campinas. Faculdade de Educação Física

Lazer e participação em um grupo de praticantes de escalada

Universidade Estadual de Campinas . Faculdade de Educação Física

O corpo que dança : os jovens e suas tribos urbanas

Universidade Estadual de Campinas . Faculdade de Educação Física

Lazer e grupos sociais ; : concepções e metodo

Universidade Estadual de Campinas . Faculdade de Educação Física