Zentrum für Molekularbiologie der Pflanzen (ZMBP)

Research Group Ragni
Periderm Development and Wood Formation

Secondary growth

Secondary growth, the increase in girth of plant organs contributed to the large success of seed plants and shaped the earth’s biosphere as we know it today. In both perennial dicots and gymnosperms, wood is the principal site of biomass accumulation, and in addition to its economic value in forestry industry provides a means for the durable sequestration of CO2. Secondary growth is mainly driven by the vascular cambium, which produces daughter cells that inward will differentiate into xylem (wood) and outward into phloem (bast). During secondary growth, the periderm replaces the epidermis as the outermost protective tissue. In stems, branches and roots of most dicots and gymnosperm, the periderm acts as the first line of defense that protects the plant against biotic and abiotic stresses limiting gas exchanges, water/solute loss and pathogen penetration.

Periderm development

The periderm, similar to the vascular system, comprises three tissues: the phellogen/cork cambium (a post-embryonic meristem) that produces inward the phelloderm and outward the phellem/cork. The barrier property of the periderm is conferred by the phellem, which is lignified and suberized. Phellem chemistry has been mainly studied in potato and cork oak due to its economic relevance, impacting potato conservation/production and the quality of cork in its application as wine-stoppers and insulating/building materials. For instance, a variety of potato resistant to common scab displays more periderm layers and increased suberin deposition in the periderm. In spite of the economical and agronomical importance, the molecular network underlying periderm establishment is largely unknown.

Our goal is to shed light on the molecular mechanisms regulating periderm development. Understanding the network underlying cork cambium formation/activity and cork maturation/ differentiation will pave the way for obtaining plants resistant to heat, drought and pathogens. Elucidating how cork cambium activity and vascular cambium activity are interconnected will help breeding programs for biomass/wood improvement.

Dr. Laura Ragni

Center for Plant Molecular Biology - ZMBP

Developmental Genetics
University of Tübingen
Auf der Morgenstelle 32
D - 72076 Tübingen, Germany

Room 5X 18

Phone: +49 (0)7071 - 29 76677

Fax: +49 (0)7071 - 29 5797
Email: laura.ragnispam prevention@zmbp.uni-tuebingen.de