Key Difference – Cork vs Bark
The main difference between cork and bark is, the bark is the protective outer layer of the tree while the cork is an outer tissue of the bark. Secondary growth enhances the size of plants resulting in woody stems and roots. This process is mainly governed by the activity of vascular cambium and cork cambium. Woody plants contain both primary and secondary tissues. Primary growth increases the length of a plant while secondary growth increases its girth. As a result of secondary growth, the plant stem and root, gain an entirely different type of organization, which includes the newly formed secondary tissues such as cork and bark. This article outlines the difference between cork and bark.
What is Cork?
Cork is a part of bark arising through the division of cork cambium cells. Cork cambium generates cuboidal cells to its outer surface that are quickly filled with suberin and replaces the epidermis of the plant. Due to the impregnation with suberin, the cork cells die, but the dead cells remain as a protective outer layer. Cork cambium and the cork, together form the periderm; the outer portion of the bark. The thickness of the cork varies among species.
Cork acts as a barrier that protects the underneath tissues from mechanical damage and prevents water loss and pathogen ingress. However, the gas exchange through the bark is quite possible to a certain extent with the presence of pores on the bark, known as lenticels. Moreover, the hollow suberized structure of the cork cells acts as an excellent barrier to polar liquids, heat, and sound. Because of this reason, the plant cork is used widely to make stoppers and insulation products.
What is Bark?
The bark is physiologically and functionally a very complex plant part. It is composed of three tissues, namely; the cork, cork cambium and secondary phloem. The bark forms the outermost layers of the trunk. The secondary phloem (the inner bark) is formed by the vascular cambium. The cork cambium is composed of cuboidal cells, which divide to form cork cells. Cork cambium has a short lifetime, unlike the vascular cambium. The main roles of the bark include wound healing, translocation and storage of organic materials and water, and protecting the inner tissues from mechanical damages and pathogens. Two regions can be distinguished within the bark of woody plants; namely, (a) inner bark, which is alive with some meristematic cells, and (b) outer bark, which consists of dead cork cells.
What is the difference between Cork and Bark?
Definition of Cork and Bark
Cork: Cork is a part of bark arising through the division of cork cambium cells.
Bark: Brak is the protective, outer layer of a woody tree.
Characteristics of Cork and Bark
Formation
Cork: Cork is formed through cork cambium.
Bark: Bark is formed through both cork and vascular cambium. Bark consists of the cork, cork cambium, and the secondary phloem.
Tissues
Cork: Cork consists of dead cells, which are filled with suberin.
Bark: Bark contains live tissues like cork cambium and secondary phloem.
Image Courtesy:
“Tree secondary components diagram” by Brer Lappin – Own work.(Public Domain) via Commons
“Cork”. Licensed under (CC BY-SA 2.5) via Wikimedia Commons
“White Oak Quercus alba Tree Bark 3264px” by Photo by and (c)2006 Derek Ramsey (Ram-Man) – Self-photographed. (CC BY-SA 2.5) via Commons
