How does tree grafting work?

497 views

How does tree grafting work?

In: Biology

Anonymous 0 Comments

First, why does plant grafting work? (I’m going to try to answer your question as it stands, thus not addressing ‘how does it work,’ or ‘how do you do it.’) The why of the whole thing is rooted in the ability of plants to adjust the chemistry of their cells to allow them to accommodate to changing environments from which they don’t have the ability to escape; also, in the complex interaction of their chemical systems, an interaction that we are only just beginning to understand.

Broadly speaking, it works because some kinds of living tissues have the ability to grow into/form bonds with/intermingle with other tissues of the correct type. In some kinds of trees, the vascular tissues of two individuals have the ability to grow together if they are placed in close contact – this is called inosculation.

In plants, the vascular tissue – that’s the tubes or vessels that transport fluids (water and minerals) throughout the plant – is contained in a layer called the cambium, which is the green area just below the skin, or bark, of the tree.

If a plant’s surface is cut, so that the vascular tubes are broken, those tissues have the ability not only regrow, but also to sort of “search” out other broken ends of their own type, and knit together with them, thus repairing the breach in the tube.

Grafting takes advantage of this natural ability of plants. People cut two plants, or pieces of plants, in a certain way, then bind them together so that the cambium layers are touching. As long as one of the cut parts is connected to viable roots, the plant’s natural abilities take over, knitting together the tubes from one plant with the tubes from the other. Then the bark grows over the wound, and voila – a grafted plant.

Interestingly, you can’t do exactly the same thing with animal tissue – you can’t cut an arm off one person, and graft in onto the leg of another, for instance – but inosculation is the process operating in skin grafting, some treatments for myocardial infarction, and probably some other medical processes as well.