SMZ1500 Fluorescence Image Gallery

Cambium Layer

Almost all vascular plants, from cedar tree to tulip, have a cambium layer. The cambium layer contains tissue that plays an important role in the growth of the plant as well as the ensuing increase in the diameter of its trunk or stem.

During growth cycles, the cambium layer contains cells that actively divide and differentiate into new conducting and supporting tissues, namely the wood (xylem) and bark or stem (phloem). Throughout its life and into maturity, a vascular plant produces certain cells -- often referred to as initials -- which begin in a state of undifferentiation; at an appropriate time, these cells demonstrate their embryonic-like capability to divide and develop into specialized tissues such as wood or bark.

Cambium tissue that contains the initial cells is also known as the lateral meristem, which exercises its greatest amount of activity during the growing season. Evidence of these growth spurts can be seen, for example, in the concentric circles found in cross sections of tree trunks (termed annual rings). In many cases, the age of a tree can be estimated by inspecting the annual rings, noting that usually the larger cell formations denote spring and the smaller formations denote the summer months. Weather and environmental conditions during certain periods of time can also be estimated from studying growth patterns recorded in annual rings.