Whatever you do, do not call kelp a “plant." For those who are not in the know: kelp (“sea kale”) is a genus of brown seaweed that is actively consumed in food and is a source of a substance called “agar-agar”, which is a vegetable substitute for gelatin. In terms of evolution, it separated from the kingdom of the plant about 1.7 billion years ago. Despite the fact that both of them are photosynthetics, in fact they are separated from each other even further than people and mushrooms.
However, a new study shows that kelp and plants have many similarities in growth systems. Like plants, the body of kelp consists of three parts: root, stem and leaf. However, the bulk (80%) falls on the leaves, while everything else is distributed between the root and the stem system. In contrast, such a shift is not observed in plants and the mass is distributed more or less evenly. The older the plant becomes, the larger its roots and stem. This is not surprising: in order to nourish the foliage carrying out photosynthesis (without which there will be no metabolism), a larger organism (for example, huge sequoias) needs very long roots and a very strong frame.
Noting the same feature in algae, scientists were very surprised: kelp does not need long roots to deliver water to the foliage, but, nevertheless, with age, the mass balance shifts to an increase in the root and stem parts. Researchers believe that this is primarily due to the fact that the roots of kelp play primarily the role of anchors that attach the algae to the substrate. Accordingly, the larger the kelp itself, the greater the load on the roots and the stronger they grow. According to botanists, in the future this discovery may be of great importance in understanding how the structure of large plants and algae will change under the influence of global climate change.