News Release

South African 'living stone' plant adapts to extreme conditions in new ways

'Living stone' employs new way to improve underground photosynthesis, minimize water loss in dry conditions

Peer-Reviewed Publication

PLOS

Anatomy of <I>Lithops aucampiae</I>

image: This image depicts the longitudinal leaf transect showing epidermis under UV light. view more 

Credit: Matthew P. Davey

A unique plant that lives underground uses multiple mechanisms to boost photosynthesis and offers new insights into how plants adapt to extreme conditions, according to new research published October 23 in the open-access journal PLOS ONE, by Katie Field and colleagues at the University of Sheffield and other institutions.

Lithops are a type of South African "living stone," a mostly underground plant that lives in extremely dry conditions. This underground life makes it difficult to get enough sun to photosynthesize while still conserving as much water as possible. Lithops has many adaptations to help it do just this, including a top surface with "windows" of translucent pockets that allows light penetration to photosynthetic tissues deep within the subterranean leaf. Cleverly, these windows also have sunscreen properties to block out harmful UV light.

But too much light can also be a problem, resulting in excess energy that cannot be used effectively for photosynthesis. To offset this excess energy and protect themselves against damage, plants with above-ground photosynthetic organs use a process known as non-photochemical quenching (NPQ).

The authors here use a combination of techniques to show that individual leaves of a Lithops species have adaptations for both high light and shade tolerance, revealing for the first time the physiological mechanisms employed to optimize above-ground and subterranean photosynthesis while minimizing water loss within its extremely dry environment. Specifically, they found local differences in surface adaptations (windows) combined with regional physiological differences in the outer cell shape and chemistry and photosynthetic mechanisms, which are dependent on whether the leaf is deep underground or just above ground. This is the first time such physiological flexibility has been observed in Lithops, and offers new insight into how plants respond and adapt to extreme conditions.

###

Citation: Field KJ, George R, Fearn B, Quick WP, Davey MP (2013) Best of Both Worlds: Simultaneous High-Light and Shade-Tolerance Adaptations within Individual Leaves of the Living Stone Lithops aucampiae. PLoS ONE 8(10): e75671. doi:10.1371/journal.pone.0075671

Financial Disclosure: This research was funded by the Natural Environment Research Council – Post-Genomics and Proteomics programme (NE/C507837/1) who financed MPD and the chlorophyll fluorescence imager equipment. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Competing Interest Statement: BF is the owner of the Abbey Brook Cactus Nursery, Derbyshire, United Kingdom (http://www.abbeybrookcacti.com). This does not alter the authors' adherence to all the PLOS ONE policies on sharing data and materials.

PLEASE LINK TO THE SCIENTIFIC ARTICLE IN ONLINE VERSIONS OF YOUR REPORT (URL goes live after the embargo ends): http://dx.plos.org/10.1371/journal.pone.0075671

Disclaimer: This press release refers to upcoming articles in PLOS ONE. The releases have been provided by the article authors and/or journal staff. Any opinions expressed in these are the personal views of the contributors, and do not necessarily represent the views or policies of PLOS. PLOS expressly disclaims any and all warranties and liability in connection with the information found in the release and article and your use of such information.

About PLOS ONE: PLOS ONE is the first journal of primary research from all areas of science to employ a combination of peer review and post-publication rating and commenting, to maximize the impact of every report it publishes. PLOS ONE is published by the Public Library of Science (PLOS), the open-access publisher whose goal is to make the world's scientific and medical literature a public resource.

All works published in PLOS ONE are Open Access. Everything is immediately available—to read, download, redistribute, include in databases and otherwise use—without cost to anyone, anywhere, subject only to the condition that the original authors and source are properly attributed. For more information about PLOS ONE relevant to journalists, bloggers and press officers, including details of our press release process and our embargo policy, see the everyONE blog at http://everyone.plos.org/media.


Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.