Skip Navigation

This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Alert me to new issues of the journal
Right arrow Add to My Personal Archive
Right arrow Download to citation manager
Right arrowRequest Permissions
Google Scholar
Right arrow Articles by ROSA, L. M.
Right arrow Articles by FORSETH, I. N.
Right arrow Search for Related Content
PubMed
Right arrow Articles by ROSA, L. M.
Right arrow Articles by FORSETH, I. N.
Agricola
Right arrow Articles by ROSA, L. M.
Right arrow Articles by FORSETH, I. N.
Social Bookmarking
Add to CiteULike   Add to Connotea   Add to Del.icio.us  
What's this?

Annals of Botany 67: 51-58, 1991
© 1991 Annals of Botany Company

RESEARCH-ARTICLE

Responses of Soybean Leaf Angle, Photosynthesis and Stomatal Conductance to Leaf and Soil Water Potential

LUIS M. ROSA, LUCIA R. DILLENBURG and IRWIN N. FORSETH*

Department of Botany, University of Maryland College Park, Maryland 20742, USA

*For Correspondence

Accepted: 29 June 1990   

The hypothesis that soil water potential ({Psi}s) is better correlated to heliotropic leaf orientation, photosaturated photosynthetic CO2 assimilation and stomatal conductance during periods of limited water availability than is bulk leaf water potential ({Psi}1) was examined in greenhouse-grown soybean (Glycine max) plants, submitted to a progressive drought. Paired plants were exposed to either 1000 or 100 µmol m–2 s–1 photon flux densities (PFD) for 45–60 mins. The higher irradiance induced short-term decreases in {Psi}1, due to increased transpiration, while {Psi}l in the plant exposed to low PFD did not decrease. These changes in {Psi}1 occurred independently of changes in soil water status. Concurrent to the light treatments, a single attached leaf from each of the two plants was isolated from the rest of the plant by shading, and the pulvinus of its terminal leaflet was exposed to a perpendicular PFD of 500 µmol m–2 S–1. Leaf movement of this leaflet was recorded in response to this light, until a stable leaflet angle was achieved. Values of {Psi}s and {Psi}l (before and after light treatment), and photosaturated rates of photosynthesis and stomatal conductance, were then measured on these leaves. Leaflet angle and gas exchange were better correlated with {Psi}s (r2 = 0.50, 0.50 and 0.57 for angle, photosynthesis and conductance, respectively) than with {Psi}l especially when {Psi}l was the result of short-term, high-light induced changes in leaf water status (r2 = 0.36, 0.32 and 0.49, for the same parameters). Leaflet angle was also correlated with stomatal conductance (r2 = 0.61) and photosynthetic rate (r2 = 0.60), suggesting a close association between leaf orientation, leaf metabolism and soil water availability.

Glycine max (L.) Merr. cv. Essex, soybean, heliotropism, water potential, photosynthesis, stomatal conductance, solar tracking


Add to CiteULike CiteULike   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us    What's this?




Disclaimer:
Please note that abstracts for content published before 1996 were created through digital scanning and may therefore not exactly replicate the text of the original print issues. All efforts have been made to ensure accuracy, but the Publisher will not be held responsible for any remaining inaccuracies. If you require any further clarification, please contact our Customer Services Department.