Root and Shoot Growth: Length vs. Width

Root and shoot growth in vascular plants happens in two main ways: primary growth and secondary growth. Primary growth makes roots and shoots longer. Secondary growth makes them thicker. Many woody plants show both kinds of growth, and the two can happen at the same time.

Primary growth happens i...

As plants grow, their roots and shoots increase in length through primary growth. In woody plants, they also increase in thickness through secondary growth.

In shoots, primary growth begins at the shoot apical meristem. Here, undifferentiated cells divide continuously. Some of these cells then differentiate into three primary meristems: th...