Some herbaceous plants develop tubers and bulbs at some stage in their development. These unique pantries contain nutrients and help plants resume their growth after the winter period. But not everyone knows how a tuber differs from a bulb. Let's try to figure it out.
Definition
Tuber is a rounded fleshy thickening that usually forms on the underground part of a number of plants, a modified shoot.
Bulb is a multi-layered, modified shoot, usually formed in plants in their underground part.
Comparison
Thus, we are talking about modified shoots, the function of which is the same - to accumulate and preserve nutrients... The main difference between a tuber and a bulb is in their development and structure.
Consider how the tuber develops. Its formation occurs at the end of an elongated horizontal shoot - a stolon. Organic matter is transported to the stolon from the leaves. The stem is their guide. The stolon gradually thickens in its apical part, the nutrients entering there are converted into starch. After a certain time, a full-fledged tuber grows in this place.
Let's analyze the structure of a ripe tuber. To do this, let us turn to the most common representative of tuberous plants - potatoes:
A tuber has a top (free side) and a base (part with a branching stolon). The surface of the tuber is uneven. On it you can see the buds (eyes), from which sprouts subsequently develop, as well as scars from leaves and internodes. The structure of the tuber proves that it is a modified shoot.
What is the difference between a tuber and a bulb? It lies in the fact that the tuber is homogeneous inside. The bulb, on the other hand, consists of densely packed layers, which are nothing more than leaves. Under the dry and thin outer leaves-scales, juicy and thick enough are hidden.
During the formation of the bulb, the newly formed leaves from the inside seem to be embedded in the existing ones. The base for the leaves is the bottom, which also gradually expands with the growth of the bulb. The bottom is a short, like a flattened stem. On it, in addition to leaves, buds arise, and roots develop from below:
The bulb also has all the signs of a shoot, but certain structural features determine the difference between it and the tuber.
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