Zeaxanthin is well suited to function as a molecular photosensor in stomatal movements

 

Photo credit: Google

Extensively Cultivated Broad Bean Vicia Faba – 

Guard cell zeaxanthin tracks photosynthetically active radiation and stomatal aperture in Vicia faba leaves.

by Srivastava A., Zeiger E. (1995b)

A. Srivastava

Eduardo Zeiger

Department of Biology, University of California, Los Angeles, CA 90024, USA

in Plant, Cell and Environment 18, 813817 – DOI: 10.1111/j.1365-3040.1995.tb00586.x –

Wiley Online Library |-

http://onlinelibrary.wiley.com/doi/10.1111/j.1365-3040.1995.tb00586.x/full

ABSTRACT

Zeaxanthin, antheraxanthin and violaxanthin concentrations in guard cells from sonicated abaxial epidermal peels of Vicia faba were measured from dawn to dusk, and compared with concentrations in mesophyll tissue of the same leaves.

Measured changes in guard cell zeaxanthin and violaxanthin concentrations indicate that guard cells operate the xanthophyll cycle throughout the day. Mesophyll tissue had no detectable zeaxanthin at dawn, whereas guard cells had 30–50 mmol mol−1chlorophyll a+b.

On a chlorophyll basis, maximal zeaxanthin levels were 3–4 fold higher in guard cells than in mesophyll cells. Zeaxanthin concentrations tracked levels of photosynthetically active radiation (PAR) in both mesophyll and guard cells.

In the mesophyll, most of the zeaxanthin changes occurred in mid-morning and mid-afternoon. In guard cells, zeaxanthin concentrations changed nearly linearly with PAR in the early morning and late afternoon, and closely tracked PAR levels throughout the day.

Guard cell zeaxanthin concentrations were also closely correlated with stomatal apertures. The close relationship between zeaxanthin concentrations and PAR levels in guard cells indicates that zeaxanthin is well suited to function as a molecular photosensor in stomatal movements.

Advertisements

Published by

Willem Van Cotthem

Honorary Professor of Botany, University of Ghent (Belgium). Scientific Consultant for Desertification and Sustainable Development.

Leave a Reply

Please log in using one of these methods to post your comment:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s