Meristematic activity of the Endodermis and the Pericycle in the primary thickening in monocotyledons: considerations on the "PTM"

Anais da Academia Brasileira de Ciências

Nanuza L. De Menezes²  Delmira C. Silva¹  Rosani C.o. Arruda¹  Gladys F. Melo-de-pinna²  Vanessa A. Cardoso²  Neuza M. Castro¹  Vera L. Scatena¹  Edna Scremin-dias¹ 

[1] ,Universidade de São Paulo Instituto de Biociências São Paulo SP ,Brasil

关键词: Cephalostemon;    Cyperus;    Echinodorus;    Lagenocarpus;    Zingiber;    meristematic endodermis;    pericycle;    primary thickening;    Cephalostemon;    Cyperus;    Echinodorus;    Lagenocarpus;    Zingiber;    endoderme meristemática;    periciclo;    espessamento primário;   

DOI  :  10.1590/S0001-37652005000200006

来源: SciELO

【 摘 要 】

This paper proposes a new interpretation for primary thickening in monocotyledons. The anatomy of the vegetative organs of the following species was examined: Cephalostemon riedelianus (Rapataceae), Cyperus papyrus (Cyperaceae), Lagenocarpus rigidus, L. junciformis (Cyperaceae), Echinodorus paniculatus (Alismataceae) and Zingiber officinale (Zingiberaceae). The endodermis with meristematic activity was observed in the root of all the species, in the stem of Cyperus, Cephalostemum and Lagenocarpus rigidus, and in the leaf trace of Cyperus and leaf of Echinodorus. Considering the continuity of tissues through the root, stem and leaf, the authors conclude that in the stem the pericycle remains active throughout the life of the plant as the generator of the vascular tissue. The "Primary Thickening Meristem" is in fact the pericycle plus the endodermis and its derivatives (or only the pericycle). Close to the stem apex, the assemblage of seems to be a unique meristem, giving rise to the inner cortex and vascular tissues.

【 授权许可】

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