I have not yet found a plant that, when an insect eats a hole in one of its leaves, it can regenerate the lost tissue. Many plants will grow a new stem if the old one is cut, but it is not a perfect regeneration, and has no likeness in form to the previous stem. Are there any plants that can, even to a degree, regenerate missing tissue?
$\begingroup$
$\endgroup$
8
-
$\begingroup$ Essentially the answer is yes, except that your qualification "but it is not a perfect regeneration, and has no likeness in form to the previous stem." is confusing me - I would consider all stems from a single plant to share a likeness in form. No, they won't be identical, but neither is a regenerated limb identical to a lost limb. $\endgroup$– David LeBauerMar 21, 2012 at 23:18
-
$\begingroup$ How about the leaves? $\endgroup$– J. MusserMar 22, 2012 at 1:48
-
$\begingroup$ same for leaves, I used stem as an example $\endgroup$– David LeBauerMar 22, 2012 at 1:49
-
1$\begingroup$ So if I punch a hole in a leaf, it can regenerate the missing tissue? $\endgroup$– J. MusserMar 22, 2012 at 13:07
-
$\begingroup$ it will generate a new leaf $\endgroup$– David LeBauerMar 23, 2012 at 5:01
|
Show 3 more comments
1 Answer
$\begingroup$
$\endgroup$
1
In general, plant cells only undergo differentiation at special regions in the plant known as meristems. Two of the primary types of meristem are the root apical meristem (at the tips of roots) and the shoot apical meristem (at shoot tips)^. Within the shoot apical meristem the plant cells divide and begin to differentiate into different cell types (such as different cells of the leaf, or vascular cells). Later growth (of, say, a leaf) is largely a result of cell expansion (although cell division does still occur, but drops off as the leaf expands). Therefore, if you punch a hole in a leaf, it probably won't be filled in because the cells in that leaf have finished growing and dividing.
However, as a shoot grows, more meristems are created. These are found in the axillary buds, just above where the leaf meets the stem. The meristems in the axillary buds can grow to form branches. Different plants obviously make different numbers of branches, but there is a common control mechanism known as apical dominance, where the meristem at the tip of the shoot suppresses the growth of the lower axillary buds. This is why a shoot with no branches can be made to grow branches by cutting off the tip (gardeners often do this to make "leggy" plants more bushy).
All of that was a long explanation to say, no, a plant doesn't normally^^ regenerate in the sense of filling in cells that have gone missing. However, if you cut off a shoot, the next remaining bud might begin to grow and, in a sense, replace the part that was lost. In that case, an existing bud is recruited to form a new branch and replace lost functionality, but I wouldn't say that qualifies as regenerating missing tissue.
^There are other types of meristem as well.
^^If you torture plant cells enough you can force them to become "stem cells" and thereby make an entirely new plant, but this is rare in nature.
-
$\begingroup$ One can tear the bark off a woody plant around the entire circumference of the stem/bole. If covered by a moisture barrier until the residual cambium cells form and epiderm, the phloem and bark will be regenerated. Furthermore, at the top of this girdling of a stem, enough auxin will accumulate to make cambium cells become stem cells and the form root initials. If surrounded with a moist medium, roots will grow (layering) - in a sense, regenerating roots, Rooting cuttings would be a more literal example of tissue regeneration analogous to a salamander regenerating a limb. $\endgroup$– user24965Jul 9, 2018 at 20:49