| Registro completo |
| Provedor de dados: |
Braz. J. Plant Physiol.
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| País: |
Brazil
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| Título: |
Effects of changes in the photosynthetic photon flux density on net gas exchange of Citrus limon and Nicotiana tabacum
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| Autores: |
Pimentel,Carlos
Ribeiro,Rafael Vasconcelos
Santos,Mauro Guida dos
Oliveira,Ricardo Ferraz de
Machado,Eduardo Caruso
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| Data: |
2004-08-01
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| Ano: |
2004
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| Palavras-chave: |
CO2 assimilation rate
Gas exchange
Stomata
Intrinsic water use efficiency
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| Resumo: |
The objective of this study was to evaluate the effects of changes in the photosynthetic photon flux density (PPFD) on net gas exchange of Citrus limon, a woody species, and Nicotiana tabacum, an herbaceous species. When PPFD was increased from 50 to 350 mumol.m-2.s-1 and returned to 50 mumol.m-2.s-1 after 60 min, the CO2 assimilation rate (A) increased and stabilized after 15 min in both species. Stomatal conductance (g s), however, continued to increase. After returning to low PPFD, A immediately diminished to a low value for both lemon and tobacco. Stomatal conductance of lemon diminished slowly over 60 min, whereas g s for tobacco took only 15 min to decrease. This difference in behavior is probably due to over-sensitivity of stomata of woody species, such as Citrus, when exposed to high light, retarding stomatal closure on return to low PPFD. Furthermore, when lemon, growing at a PPFD of 300 mumol.m-2.s-1, was submitted to a step increase of 600 mumol.m-2.s-1, there was an oscillatory behavior of A and g s requiring 150 min to stabilize. The causes of this behavior are discussed with respect to improved intrinsic water use efficiency by stomatal closure.
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| Tipo: |
Info:eu-repo/semantics/article
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| Idioma: |
Inglês
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| Identificador: |
http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1677-04202004000200002
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| Editor: |
Brazilian Journal of Plant Physiology
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| Relação: |
10.1590/S1677-04202004000200002
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| Formato: |
text/html
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| Fonte: |
Brazilian Journal of Plant Physiology v.16 n.2 2004
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| Direitos: |
info:eu-repo/semantics/openAccess
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