The contribution of weak CAM to the photosynthetic metabolic activities of a bromeliad species under water deficit.

Autor: Pikart FC; Departamento de Biologia Vegetal, Instituto de Biologia, Universidade Estadual de Campinas, CP 6109, CEP 13083-970, Campinas, Brazil; Departamento de Botânica, Instituto de Biociências, Universidade de São Paulo, Rua do Matão, nº277, CEP 05508-090, São Paulo, Brazil. Electronic address: pikart@usp.br., Marabesi MA; Núcleo de Pesquisa em Fisiologia e Bioquímica, Instituto de Botânica, CP 3005, CEP 01061-970, São Paulo, Brazil., Mioto PT; Departamento de Botânica, Instituto de Biociências, Universidade de São Paulo, Rua do Matão, nº277, CEP 05508-090, São Paulo, Brazil; Departamento de Botânica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Campus Reitor João David Ferreira Lima, s/n, 88040-900, Florianópolis, Brazil., Gonçalves AZ; Departamento de Botânica, Instituto de Biociências, Universidade de São Paulo, Rua do Matão, nº277, CEP 05508-090, São Paulo, Brazil., Matiz A; Departamento de Botânica, Instituto de Biociências, Universidade de São Paulo, Rua do Matão, nº277, CEP 05508-090, São Paulo, Brazil., Alves FRR; Departamento de Botânica, Instituto de Biociências, Universidade de São Paulo, Rua do Matão, nº277, CEP 05508-090, São Paulo, Brazil; Laboratório de Fisiologia Vegetal, Departamento de Botânica, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Avenida Esperança, s/n, Campus Samambaia, 74690-900, Goiânia, Brazil., Mercier H; Departamento de Botânica, Instituto de Biociências, Universidade de São Paulo, Rua do Matão, nº277, CEP 05508-090, São Paulo, Brazil., Aidar MPM; Núcleo de Pesquisa em Fisiologia e Bioquímica, Instituto de Botânica, CP 3005, CEP 01061-970, São Paulo, Brazil.
Jazyk: angličtina
Zdroj: Plant physiology and biochemistry : PPB [Plant Physiol Biochem] 2018 Feb; Vol. 123, pp. 297-303. Date of Electronic Publication: 2017 Dec 19.
DOI: 10.1016/j.plaphy.2017.12.030
Abstrakt: The Crassulacean acid metabolism (CAM) can be a transitory strategy for saving water during unfavourable conditions, like a dry season. In some cases, CAM can also contribute to the maintenance of photosynthetic integrity, even if carbon gain and growth are impaired. CAM occurs in different intensities, being stronger or weaker depending on the degree of nocturnal malic acid accumulation. For example, Guzmania monostachia is an epiphytic tank bromeliad that shows an increase in its nocturnal organic acid accumulation and a variable CAM behaviour when exposed to water deficit. In this context, this study aimed at investigating whether the weak CAM displayed by this species may mitigate the harmful effects of water limitation on its photosynthetic activity. To this, bromeliads were submitted to well-watered and water deficit conditions. Guzmania monostachia plants under water deficiency conditions showed a reduction on atmospheric carbon assimilation without exhibiting changes in PSII integrity and carbohydrate production while showed an increase in nocturnal malic acid accumulation. Additionally, spots with high PSII efficiency in the leaf portion with a greater nocturnal malic acid accumulation were observed in plants exposed to water shortage conditions. These high-efficiency spots might be associated with a greater malate decarboxylation capacity. Also, the malic acid contributed to approximately 50% of the total carbon assimilated under water deficit. These results suggest that weak CAM may participate in photo-protection and it appears to meaningfully contribute to the overall carbon balance, being an important metabolic strategy to maintain plant fitness during water deficit periods.
(Copyright © 2017 Elsevier Masson SAS. All rights reserved.)
Databáze: MEDLINE
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