Stomatal penetration by aqueous solutions – an update involving leaf surface particles
Article first published online: 17 SEP 2012
© 2012 The Authors. New Phytologist © 2012 New Phytologist Trust
Volume 196, Issue 3, pages 774–787, November 2012
How to Cite
Burkhardt, J., Basi, S., Pariyar, S. and Hunsche, M. (2012), Stomatal penetration by aqueous solutions – an update involving leaf surface particles. New Phytologist, 196: 774–787. doi: 10.1111/j.1469-8137.2012.04307.x
- Issue published online: 9 OCT 2012
- Article first published online: 17 SEP 2012
- Manuscript Accepted: 29 JUL 2012
- Manuscript Received: 2 MAY 2012
- Theodor-Brinkmann Graduate School of the Agricultural Faculty. Grant Number: BU 1099/7-1
- active ingredients;
- environmental scanning electron microscope (ESEM);
- Hofmeister series;
- hydraulic activation of stomata;
- leaf boundary layer
- The recent visualization of stomatal nanoparticle uptake ended a 40-yr-old paradigm. Assuming clean, hydrophobic leaf surfaces, the paradigm considered stomatal liquid water transport to be impossible as a result of water surface tension. However, real leaves are not clean, and deposited aerosols may change hydrophobicity and water surface tension.
- Droplets containing NaCl, NaClO3, (NH4)2SO4, glyphosate, an organosilicone surfactant or various combinations thereof were evaporated on stomatous abaxial and astomatous adaxial surfaces of apple (Malus domestica) leaves. The effects on photosynthesis, necrosis and biomass were determined. Observed using an environmental scanning electron microscope, NaCl and NaClO3 crystals on hydrophobic tomato (Solanum lycopersicum) cuticles underwent several humidity cycles, causing repeated deliquescence and efflorescence of the salts.
- All physiological parameters were more strongly affected by abaxial than adaxial treatments. Spatial expansion and dendritic crystallization of the salts occurred and cuticular hydrophobicity was decreased more rapidly by NaClO3 than NaCl.
- The results confirmed the stomatal uptake of aqueous solutions. Humidity fluctuations promote the spatial expansion of salts into the stomata. The ion-specific effects point to the Hofmeister series: chaotropic ions reduce surface tension, probably contributing to the defoliant action of NaClO3, whereas the salt spray tolerance of coastal plants is probably linked to the kosmotropic nature of chloride ions.