A tomato from our garden got a crack and stitched itself...
Geege Schuman stashed this in Botany
How cool! Can all plants do that?
Let’s clarify a few points first. Gil, living tissue in the form of ray parenchyma penetrates the heartwood of trees and is connected to the other living tissues you mentioned. So the heartwood is not “dead,” though the xylem elements in it are. The material that “bleeds and forms a scab like structure” includes callose (a specialized sugar) and various sticky compounds found in resin ducts and elsewhere. Often these include antibiotic chemicals to kill insects or microbes. Scabs that form over animal wounds are chemically dissimilar. And scabs form over the top of the wound, period, while resin, etc. flow and cover whatever surface they meet. They may have some similar properties, but they are not the same thing.
Further, plant physiologists do not consider plants to have an immune system in the same sense that animals do. Plants do not have T cells or B cells or lymph nodes. They do have defensive responses, however, including hypersensitive responses (their reaction to foliar fungi, for example) and systemic acquired resistance.All that being said, it’s the difference between healing (actual replacement of damaged tissues with the same type of tissue) and sealing (isolating and covering wounds with a different type of tissue) that I’m curious about. Are the tissues that form in a graft the same as those that were damaged? I would assume yes – but I don’t know. Which is why I’m hoping some other GP type familiar with grafting can weigh in here.
Again, it’s more than a semantic argument. The danger is when people think that plants have the same physiological responses to stresses that animals do, they tend to make plant care decisions not necessarily in the best interest of the plant.
Plant damage is so common we have learned to live with it.
Thanks! Plant damage is so common I never really thought about it till now.