Abstract Detail

Developmental and Structural Section

C. Vitarelli, Narah [4], Riina, Ricarda [1], Rossi Caruzo, Maria Beatriz [2], Cordeiro, Ines [3], Fuertes Aguilar, Javier [1], STROZI ALVES MEIRA , RENATA MARIA [4].

Diversity of leaf secretory structures in Croton sect. Cleodora and Lamprocroton and allied genera.

The genus Croton stands out for its diversity of chemical compounds and wide use in folk medicine. Although several compounds have already been identified, there are few anatomical studies describing the structures responsible for the secretion of such compounds and the sites where they are produced.  The aim of this study was to identify and examine the diversity of secretory structures in Croton and its close allies in the light of recent phylogenetic studies. Twenty-four species of Croton (12 sect. Cleodora and 12 sect. Lamprocroton), Astraea lobata and Brasiliocroton mamoninha were studied by means of standard anatomical techniques. Five types of secretory structures were identified: laticifers, colleters, extrafloral nectaries, secretory idioblasts and secretory trichomes. Laticifers occur in all species studied but C. alabamensis which presents secretory parenchyma cells instead. The standard type of colleter appears to be a common structure in Croton as they occur in all species of sect. Cleodora and almost all species of sect. Lamprocroton. Colleters were also found in the close allies Astraea lobata and Brasiliocroton mamoninha. Extrafloral nectaries are diagnostic structures for sect. Cleodora and Brasiliocroton mamoninha while their absence is characteristic for sect. Lamprocroton and Astraea lobata. Secretory idioblasts are spread among the palisade and/or spongy parenchyma in all species but C. alabamensis, C. pygmaeus and C. splendidus. Single-celled secretory trichomes are restricted to sect. Lamprocroton except for C. imbricatus. The type of secretory structure, their position and distribution among the taxa are relevant for taxonomy.  The diversity of secretory structures is an important source of data that may contribute to our understanding of species relationships within tribe Crotoneae, shedding light on its evolutionary history and morphological diversification.   The authors wish to thank CPNq, CAPES, FAPEMIG and Floresta Escola for research grants and/or financial support and curators of the herbaria for allowing material samplings.

1 - Real Jardín Botánico, RJB-CSIC, Plaza de Murillo 2,, Madrid , 28036, Spain
2 - Universidade Federal de São Paulo, Departamento de Ciências Exatas e da Terra, Setor de Educação em Ciências. , Rua Prof. Arthur Riedel, 275 Eldorado, Diadema, São Paulo, 09972-270, Brazil
3 - Instituto de Botânica, Divisão de Fitotaxonomia, Seção de Curadoria do Herbário, Av. Miguel Stefano, 3687, São Paulo, São Paulo, 04301-012, Brazil
4 - UNIVERSIDADE FEDERAL DE VIÇOSA, Av. P. H. Rolfs, S/n, Centro, Campus UFV, Viçosa/Minas Gerais, N/A, 36570-000, Brazil

Keywords:
colleters
Euphorbiaceae
extrafloral nectaries
laticifers
secretory idioblasts
secretory trichomes.

Presentation Type: Oral Paper:Papers for Sections
Session: 20
Location: Pines North/Boise Centre
Date: Tuesday, July 29th, 2014
Time: 9:00 AM
Number: 20004
Abstract ID:302
Candidate for Awards:None