Advanced search
Start date
Betweenand
Related content
(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Leaf paraheliotropism in Styrax camporum confers increased light use efficiency and advantageous photosynthetic responses rather than photoprotection

Full text
Author(s):
Habermann, Gustavo [1] ; Ellsworth, Patricia F. V. [2] ; Cazoto, Juliana L. [3] ; Feistler, Aline M. [1] ; da Silva, Leandro [4] ; Donatti, Dario A. [5] ; Machado, Silvia R. [6]
Total Authors: 7
Affiliation:
[1] Univ Estadual Paulista, UNESP, Dept Bot, IB, BR-13506900 Rio Claro, SP - Brazil
[2] Univ Miami, Dept Biol, Coral Gables, FL 33124 - USA
[3] Univ Estadual Campinas, UNICAMP, Dept Biol Vegetal, IB, BR-13083970 Campinas, SP - Brazil
[4] Inst Agron Campinas, Ctr Ecofisiol & Biofis, BR-13001970 Campinas, SP - Brazil
[5] Univ Estadual Paulista, UNESP, Dept Fis, IGCE, BR-13506900 Rio Carlo, SP - Brazil
[6] Univ Estadual Paulista, UNESP, Dept Bot, IB, BR-18618000 Botucatu, SP - Brazil
Total Affiliations: 6
Document type: Journal article
Source: ENVIRONMENTAL AND EXPERIMENTAL BOTANY; v. 71, n. 1, p. 10-17, APR 2011.
Web of Science Citations: 11
Abstract

Styrax caporum is a native shrub from the Brazilian savanna. Most of its leaves are diaheliotropic, whereas some are paraheliotropic, mainly at noon. A previous study of this species revealed higher stomatal conductance (gs) and transpiration rates (E) in para- compared to diaheliotropic leaves, and a rise in CO(2) assimilation rates (A) with an increase of irradiance for paraheliotropic leaves. We hypothesized that this species exploits the paraheliotropism to enhance the light use efficiency, and that it is detected only if gas exchange is measured with light interception by both leaf surfaces. Gas exchange was measured with devices that enabled light interception on only one of the leaf surfaces and with devices that enabled light interception by both leaf surfaces. Water relations, relative reflected light intensity, leaf temperature (T(l)), and leaf anatomical analyses were also performed. When both leaf surfaces were illuminated, a higher A. E, and gs were observed in para- compared to diaheliotropic leaves; however, A did not depend on gs, which did not influence CO(2) accumulation in the stomatal cavity (Ci). When only the adaxial leaf surface was illuminated, a greater A was detected for para- than for diaheliotropic leaves only at 11:00 h; no differences in T(l) were observed between leaf types. Light curves revealed that under non-saturating light the adaxial side of paraheliotropic leaves had higher A than the abaxial side, but they showed similar values under saturating light. Although the abaxial leaf side was highly reflective, both surfaces presented the same response pattern for green light reflection, which can be explained by the compact spongy parenchyma observed in the leaves, increasing light use efficiency in terms of CO(2) consumption for paraheliotropic leaves. We propose that paraheliotropism in S. camporum is not related to leaf heat avoidance or photoprotection. (C) 2010 Elsevier B.V. All rights reserved. (AU)

FAPESP's process: 09/04007-4 - Chlorophyll A gas exchange and fluorescence measurements in paraheliotropic leaves of Styrax camporum Pohl. under water stress
Grantee:Aline Mariani Feistler
Support Opportunities: Scholarships in Brazil - Master