meristemas

Hoehnea 36(4): 525-549, 3 fig., 2009

525

Meristemas: fontes de juventude e plasticidade no desenvolvimento vegetal
Maria Aurineide Rodrigues1 e Gilberto Barbante Kerbauy1,2
Recebido: 30.07.2009; aceito: 06.11.2009

ABSTRACT - (Meristems: Sources of youth and plasticity in plant development). Plants are sessile organisms which are able to overcome environmental adversities due to their exceptional developmental plasticity, an attribute mainly conferred by the meristems. In these specialized tissues are found the self-renewing stem cells that maintain the meristematic identity, as well as the derived cellular progenies involved in the formation of several tissues and new organs. The diversity of cellular identities in both apical meristems and surrounding tissues is tightly controlled by positional exchange of intercellular signals such as transcription factors and plant hormones. The various cues acting on meristematic activity regulation are integrated in signaling networks that have been discovered in plant models, thereby, improving our understanding in this field of research. Currently, increasing interest has been observed in comparative analyses regarding the conservation of the developmental mechanisms controlling the meristematic activity among different plant species.
Key words: hormones, plant growth, stem cells, transcription factors
RESUMO - (Meristemas: Fontes de juventude e plasticidade no desenvolvimento vegetal). As plantas são organismos sésseis capazes de adequarem-se às diferentes condições ambientais por apresentarem uma considerável plasticidade de desenvolvimento, conferida, principalmente, pelos meristemas. Nestes tecidos encontram-se as células-tronco capazes de se auto-perpetuarem, mantendo a identidade meristemática, bem como as células derivadas de sua atividade, estas comprometidas com a formação dos diferentes tecidos e órgãos. As identidades das populações celulares nos meristemas apicais e tecidos