Morfoanatomia e ontogênese do pericarpo de Manihot caerulescens Pohl e M. tripartita Müll. Arg. (Euphorbiaceae)

Abstract

-(Morphology, anatomy and ontogeny of the pericarp of Manihot caerulescens Pohl and M. tripartita Müll. Arg. (Euphorbiaceae)). Manihot caerulescens and M. tripartita are shrub species of cerrado, known as "mandioca-brava". Works on structure of pericarp of Euphorbiaceae are rare and many of the found morphologic descriptions present dubious interpretations, especially on the dehiscence. The present work aimed to describe the morphology, anatomy and ontogeny of pericarp of the two species of Manihot, comparing themselves and relating structural aspects of pericarp to the dehiscence. We verified that the pericarp follow four developmental periods, as typical of dry fruits. Two meristems are formed: a subadaxial, that produces the inner mesocarp; and another adaxial, that forms the endocarp, homogeneous and collenchymatous in M. caerulescens, and heterogeneous in M. tripartita, with outer gelatinous fiber-sclereids and an collenchymatous inner portion. We observed the formation of separation tissue, composed of loose parenchyma, in direction to the dorsal bundle of the three carpels and to the septa, which are more evident in M. tripartita. Finally, we verified variation in the sclerenchymatous stratum: in M. caerulescens, there is a layer of fiber-sclereids and one of stone cells, both of the mesocarp; in M. tripartita, these two mesocarpic layers occur, with bigger thickness, increased of the outer endocarp, also composed of fiber-sclereids. The fruits of both species are capsules which type depends on the development of separation tissue and of the dimension of sclerenchymatous stratum. Thus M. caerulescens presents indehiscent capsules, while M. tripartita forms septi-loculicidal capsules, since the dehiscence, even so passive, occurs in the dorsal regions and in the direction to septa.Key words -anatomy, development, Manihot, morphology, pericarp RESUMO -(Morfoanatomia e ontogênese do pericarpo de Manihot caerulescens Pohl e M. tripartita Müll. Arg. (Euphorbiaceae)).Manihot caerulescens e M. tripartita são espécies arbustivas de cerrado, conhecidas como mandiocabrava. Não são encontrados muitos trabalhos sobre estrutura do pericarpo de Euphorbiaceae e muitas das descrições morfológicas existentes apresentam interpretações dúbias, especialmente sobre a deiscência. O presente trabalho objetivou descrever a morfologia, anatomia e ontogênese do pericarpo das duas espécies de Manihot, comparando-as entre si e relacionando aspectos estruturais do pericarpo à deiscência. Verificou-se que o desenvolvimento do pericarpo enquadra-se em quatro estágios, típicos de frutos secos. Dois meristemas são formados: um subadaxial, que produz o mesocarpo interno; outro adaxial, que forma o endocarpo, homogêneo e colenquimatoso em M. caerulescens, e heterogêneo em M. tripartita, com fibroesclereídes gelatinosas externas e uma porção colenquimatosa interna. Observou-se a formação de tecido de separação, composto por parênquima laxo, em direção aos feixes dorsais dos três carpelos e aos septos, o qual é mais evidente em M. t...

Caracterização morfoanatomica e fisiológica de sementes e plântulas de Jatropha curcas L. (Euphorbiaceae)

“…São albuminosas, elípticas e anátropas. Oliveira (2007), em seu estudo com duas espécies da família Euphorbiaceae, gênero Manihot, M. caerulescens Pohl. e M. tripartita Mull.…”

“…(AÑEZ et al, 2005), Manihot caerulescens Pohl, Manihot tripartita Mull Arg. (OLIVEIRA, 2007) e Cnidosculus juercifolius Paxe K. Hoffm. (SILVA et al, 2007), que podem ser utilizados como base para comparação dos estudos realizados com a espécie em questão.…”

Pericarp ontogeny and histochemistry of the exotesta and pseudocaruncle of Euphorbia milii (Euphorbiaceae)

“…There are many anatomical studies on the Euphorbiaceae seeds, but few studies on the structure of the fruits have been carried out (Sablon 1884;Lavialle & Delacroix 1922 a,b,c;Oliveira & Oliveira 2009), and only Lavialle & Delacroix (1922a) have studied the ontogeny of the fruits in Euphorbia L. species. The researches are usually restricted to the analysis of the seeds, of which size, shape, ornamentation, seed coat anatomy, development of the endosperm and configuration of the embryo are taxonomically important characteristics, specially to the generic and specific levels (Jordan & Hayden 1992;Simon et al 1992;Webster 1994).…”

“…Secretory structures are rare in Euphorbiaceae fruits and little to no emphasis is given to them in the few anatomic studies already made. The data contained in literature basically refer to the presence of the caruncle (elaiosome), secretory exotesta and sarcotesta in some few species (Jordan & Hayden 1992;Webster 1994;Lisci et al 1996;Tokuoka & Tobe 2002), and there are few studies reporting the presence of laticifers and secretory idioblasts at the pericarp (Lavialle & Delacroix 1922a,b,c;Jimenez & Morales 1978;Oliveira & Oliveira 2009). …”

“…Arg. (Oliveira & Oliveira 2009) and Euphorbia (Subils 1977;Jimenez & Morales 1978), except for a few cases, such as Mercurialis annua L., whose fruit is a capsule with two lobes separated by a septum (Lisci & Pacini 1997).…”