Data/hora: 23/09/2024 21:53:03

Biblioteca(s): 	Embrapa Semiárido.	
Data corrente: 	26/08/2014	
Data da última atualização: 	26/08/2014	
Autoria: 	AIDAR, S. de T.; MEIRELLES, S. T.; OLIVEIRA, R. F.; CHAVES, A. R. de M.; FERNANDES JUNIOR, P. I.	
Afiliação: 	SAULO DE TARSO AIDAR, CPATSA; S. T. MEIRELLES, Instituto de Biociências, Universidade de São Paulo; R. F. OLIVEIRA, Escola Superior de Agricultura Luiz de Queiroz; AGNALDO RODRIGUES DE MELO CHAVES, CPATSA; PAULO IVAN FERNANDES JUNIOR, CPATSA.	
Título: 	Photosynthetic response of poikilochlorophyllous desiccation-tolerant Pleurostima purpurea (Velloziaceae) to dehydration and rehydration.	
Ano de publicação: 	2014	
Fonte/Imprenta: 	Photosynthetica, v. 52, n. 1, p. 124-133, 2014.	
DOI: 	10.1007/s11099-014-0014-0	
Idioma: 	Inglês	
Conteúdo: 	The poikilochorophyllous, desiccation-tolerant (PDT) angiosperm, Pleurostima purpurea, normally occurs in less exposed rock faces and slightly shady sites. Our aim was to evaluate the light susceptibility of the photosynthetic apparatus during dehydration-rehydration cycle in P. purpurea. In a controlled environment, the potted plants were subjected to water deficit under two different photosynthetic photon flux densities [PPFD, 100 and 400 &#956;mol(photon) m?2 s?1]. In the higher PPFD, net photosynthetic rate (PN) become undetectable after stomata closure but photochemical efficiency of photosystem II, electron transport rate, and photochemical quenching coefficient were maintained relatively high, despite a partial decrease. The photochemical activity was inhibited only after the complete loss of chlorophylls, when leaf relative water content dropped below 72% and total carotenoids reached maximal accumulation. Nonphotochemical energy dissipation increased earlier in response to dehydration under higher PPFD. PN and photochemical activity were fully recovered after rehydration under both light treatments. Our results suggested that the natural occurrence of P. purpurea should not be restricted by the light intensity during the complete desiccation-rehydration cycles. Additional key words: chlorophyll fluorescence; gas exchange; photoprotective mechanisms; vegetative desiccation tolerance	
Palavras-Chave: 	Chlorophyll fluorescence; Fluorescência da clorofila; Photoprotective mechanisms; Planta nativa; Planta tolerante a seca; Pleurostima purpurea; Poikilochorophyllous; Troca de gás.	
Thesagro: 	Caatinga; Planta.	
Thesaurus Nal: 	Gas exchange; Velloziaceae.	
Categoria do assunto: 	P Recursos Naturais, Ciências Ambientais e da Terra	
URL: 	http://ainfo.cnptia.embrapa.br/digital/bitstream/item/107278/1/Agnaldo-1.pdf	
Registro original: 	Embrapa Semiárido (CPATSA)	
Exemplares: 	CPATSA - (53277-1) - UPC - AP - DD -  -  -  - DIS