Holly Bushes and Epigenetics

Discussion in 'Plants: Science and Cultivation' started by 1Down5Up, Dec 10, 2022.

  1. 1Down5Up

    1Down5Up New Member

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    I was reading about the idea that Holly will drop its round leaves and grow spiked defensive ones in their place after animals have fed from the plant. I just read a post on this forum from someone wondering why the leaves were falling off her holly bush when the birds were foraging (don’t think they were eating the leaves but the physical contact could mimic that of a deers), could be a related thing.

    My question is if anybody has observed this and also, does anybody know for a fact what type of leaves grow after the spiky variant are shed?
  2. Margot

    Margot Generous Contributor 10 Years

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    Nanoose Bay, BC Canada
    This came up today on another group so I've been trying to find out if it is true or not.

    "Did you know that if holly (Ilex aquifolium) finds its leaves are being nibbled by deer, it switches genes on to make them spiky when they regrow? So on taller holly trees, the upper leaves (which are out of reach) have smooth edges, while the lower leaves are prickly." americanforests.org

    From National Geographic: "Carlos Herrera .......... and his team investigated the European holly tree, Ilex aquifolium. Hollies, like other plants, can make different types of leaves at the same time. This is called heterophylly. Out of the 40 holly trees they studied, 39 trees displayed different kinds of leaves, both prickly and smooth." Hollies Get Prickly for a Reason

    I didn't read thoroughly yet so don't know what type of leaves grow after the spiky variant are shed. I don't remember ever seeing smooth-edged leaves on a holly tree the deer bothered from time to time. (I took it down after realizing hollies are on the invasive plant list for my area.)

    Since my holly tree has been gone, literally hundreds of seedlings have been germinating all over the garden . . . it's almost like they know mama needs replacing. Each and every one of the seedlings I have pulled has prickly leaves right from the get go, ie. no browsing to cause them to be defensive.
    wcutler likes this.
  3. Ron B

    Ron B Paragon of Plants 10 Years

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    WA USA (Z8)
    I just read a post on this forum from someone wondering why the leaves were falling off her holly bush

    Holly (Ilex spp.)-Phytophthora Leaf and Twig Blight | Pacific Northwest Pest Management Handbooks (pnwhandbooks.org)

    Spiny down low and non spiny up high is typical behavior for non-variant Ilex aquifolium anyway.

    Ordinary seed-raised young trees have very wavy leaves with large, triangular, outstanding teeth 1⁄2 in. long; but as they increase in height the leaves of the upper branches become less spiny, until finally the tops of good-sized trees will be found almost wholly furnished with quite entire leaves

    Ilex aquifolium - Trees and Shrubs Online
    Last edited: Dec 10, 2022
  4. togata57

    togata57 Generous Contributor 10 Years

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    Columbus, Ohio
    ...But it’s actually the fact that plants are fixed that makes them so interesting. They can’t run from predators or chase after prey, so they’ve evolved all kinds of clever tactics to survive. “Plants are way more complicated than people give them credit for,” said Elizabeth Haswell, a professor and plant biologist at Washington University in St. Louis.

    The mystery of the mimic plant
  5. davidrt28

    davidrt28 Member

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    Maryland, USA
    Osmanthus can do the same thing, especially Osmanthus heterophyllus, as the name implies! But I wonder if some popular cultivars have permanently juvenile foliage.
  6. Daniel Mosquin

    Daniel Mosquin Paragon of Plants UBC Botanical Garden Forums Administrator Forums Moderator 10 Years

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    Vancouver, British Columbia, Canada
    Does it have to involve epigenetics? It could be ramping up of a hormone due to a wound response which then pushes leaf development into a particular mode -- no genetic change, though it is within the genetic capacity to have different leaf morphs.

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