Home News About Us Contact Contributors Disclaimer Privacy Policy Help FAQ

Quick Search
My eDoc
Session History
Support Wiki
Direct access to
document ID:

          Institute: MPI für Meteorologie     Collection: Atmosphere in the Earth System     Display Documents

ID: 474937.0, MPI für Meteorologie / Atmosphere in the Earth System
Optics of sunlit water drops on leaves: Conditions under which sunburn is possible
Authors:Egri, Á.; Horváth, Á.; Kriska, G.; Horváth, G.
Date of Publication (YYYY-MM-DD):2010-03
Title of Journal:New Phytologist
Start Page:979
End Page:987
Review Status:not specified
Audience:Not Specified
Abstract / Description:It is a widespread belief that plants must not be watered in the midday sunshine, because water drops adhering to leaves can cause leaf burn as a result of the intense focused sunlight. The problem of light focusing by water drops on plants has never been thoroughly investigated. Here, we conducted both computational and experimental studies of this phyto-optical phenomenon in order to clarify the specific environmental conditions under which sunlit water drops can cause leaf burn. We found that a spheroid drop at solar elevation angle θ ≈ 23°, corresponding to early morning or late afternoon, produces a maximum intensity of focused sunlight on the leaf outside the drop's imprint. Our experiments demonstrated that sunlit glass spheres placed on horizontal smooth Acer platanoides (maple) leaves can cause serious leaf burn on sunny summer days. By contrast, sunlit water drops, ranging from spheroid to flat lens-shaped, on horizontal hairless leaves of Ginkgo biloba and Acer platanoides did not cause burn damage. However, we showed that highly refractive spheroid water drops held 'in focus' by hydrophobic wax hairs on leaves of Salvinia natans (floating fern) can indeed cause sunburn because of the extremely high light intensity in the focal regions, and the loss of water cooling as a result of the lack of intimate contact between drops and the leaf tissue. © The Authors (2010)
Free Keywords:Environmental optics; Leaf burn; Phyto-optics; Plant leaf; Ray tracing; Solar radiation; Sunburn; Water drop
External Publication Status:published
Document Type:Article
Communicated by:Carola Kauhs
Affiliations:MPI für Meteorologie/Atmosphere in the Earth System
URL:http://www3.interscience.wiley.com/journal/1232363... [Verlagsseite]
Full Text:
Sorry, no privileges
The scope and number of records on eDoc is subject to the collection policies defined by each institute - see "info" button in the collection browse view.