Why does bamboo have knots?

Nodes are the middle meristem of bamboo. Bamboo is a monocotyledonous plant, and the apical meristem lasts for a short time. Usually, when bamboo shoots are unearthed, the apical meristem has stopped moving and the nodes and internodes have differentiated. The future growth is mainly the result of mesenchymal tissue, which is the activity of nodes.

Although bamboo grows very tall, it is a gramineous plant. The biggest feature of Gramineae plants is that the stems are segmented, and there are solid nodes between nodes, where branches and leaves can grow.

Generally, plants only have growth tissues at the top, while every node of bamboo has growth tissues, and new cells are constantly produced, so bamboo will grow quickly. If bamboo has 30 knots, its growth rate is 30 times that of other plants. Therefore, the fastest growing plant in the world is bamboo. In rainy season, when bamboo grows fastest, it can reach 150-200 cm every day and night, and when it grows slowest, it can reach 20-30 cm every day and night. Of course, different kinds of bamboo grow at different speeds. For example, Phyllostachys pubescens can grow15-18m in 30-40 days, and Phyllostachys pubescens 100- 120 days can grow 30-35m.

According to the theory of plant evolution, ancient bamboo should be solid. In the process of evolution, the "pith" in the center of the stem gradually shrank and disappeared, becoming a hollow tubular structure. Such a structure can reduce the weight of plant stems, improve the lodging resistance of plants, and enhance the supporting ability in varieties with the same thickness and height. Bamboo was born without secondary tissue. When the stem grows to a certain thickness, it is no longer thick. From the mechanical point of view, the material with the same composition produces a hollow and thick column, which has stronger supporting force than the solid and thin column in the middle and becomes a tubular structure.