Trichomes related to an unusual method of water retention and protection of the stem apex in an arid zone perennial species

Autor(es)

Lusa, Makeli Garibotti ^{[1, 2]} ; Cardoso, Elaine Cristina ^[1] ; Machado, Silvia Rodrigues ^[3] ; Appezzato-da-Gloria, Beatriz ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Escola Super Agr Luiz de Queiroz, Dept Ciencias Biol, BR-13418900 Piracicaba, SP - Brazil

^[2] Univ Estadual Campinas, Inst Biol, Programa Posgrad Biol Vegetal, BR-13083970 Campinas, SP - Brazil

^[3] Univ Estadual Paulista, Inst Biociencias, Dept Bot, BR-18618000 Botucatu, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: AOB PLANTS; v. 7, 2015.
• Citações Web of Science: 10

Resumo

It is well known that trichomes protect plant organs, and several studies have investigated their role in the adaptation of plants to harsh environments. Recent studies have shown that the production of hydrophilic substances by glandular trichomes and the deposition of this secretion on young organs may facilitate water retention, thus preventing desiccation and favouring organ growth until the plant develops other protective mechanisms. Lychnophora diamantinana is a species endemic to the Brazilian `campos rupestres' (rocky fields), a region characterized by intense solar radiation and water deficits. This study sought to investigate trichomes and the origin of the substances observed on the stem apices of L. diamantinana. Samples of stem apices, young and expanded leaves were studied using standard techniques, including light microscopy and scanning and transmission electron microscopy. Histochemical tests were used to identify the major groups of metabolites present in the trichomes and the hyaline material deposited on the apices. Non-glandular trichomes and glandular trichomes were observed. The material deposited on the stem apices was hyaline, highly hydrophilic and viscous. This hyaline material primarily consists of carbohydrates that result from the partial degradation of the cell wall of uniseriate trichomes. This degradation occurs at the same time that glandular trichomes secrete terpenoids, phenolic compounds and proteins. These results suggest that the non-glandular trichomes on the leaves of L. diamantinana help protect the young organ, particularly against desiccation, by deposition of highly hydrated substances on the apices. Furthermore, the secretion of glandular trichomes probably repels herbivore and pathogen attacks. (AU)

• Processo FAPESP: 10/51454-3 - Estudos morfoanatômicos, metabolômicos e moleculares como subsídios à sistemática de espécies de Asteraceae e acesso ao seu potencial farmacológico
• Beneficiário: Beatriz Appezzato da Glória
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 10/02085-5 - Morfoanatomia e fitoquímica de espécies da subtribo Lychnophorinae (Asteraceae: Vernonieae) como subsídios para a análise filogenética do grupo
• Beneficiário: Makeli Garibotti Lusa
• Modalidade de apoio: Bolsas no Brasil - Doutorado