Undeveloped 'seed'

Discussion in 'Plants: Science and Cultivation' started by Gwen Miller, Mar 6, 2020.

  1. Gwen Miller

    Gwen Miller Member

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    Please help me understand seed and fruit formation.
    At a good Fraser Valley nursery last fall the owner showed our good-sized group a seed pod. I recall it looked like one of those lumpy reddish magnolia pods. He mentioned to the group "Look, you can see from the pod where unfertilized (undeveloped) seed is." This comment rocked my world! So much so that some of the details are a bit fuzzy. An unfertilized SEED??? A seed is an embryo - how can it be unfertilized? I was so stunned, I didn't ask for clarification. Did the plantsman actually mean unfertilized potential rather than seeds? Am I being too literal and quibbling over terminology?
    That left me pondering about unfertilized ova, and fruit formation, and if/how the plant determines that the fertilization rate is high enough to make a fruit. I found an interesting discussion about attempts to breed infertility into decorative plants, but that's not the same as my question. (What is the defineition of plant sterility (infertile), and what...)

    Thinking about this, I saved what I found after juicing a lemon. There were many infinitesimal 'seeds,' pic attached. What are they? Unfertilized ova? And my partner read that his atrophied young zucchinis, several inches long, are rejected from further development because they're not fertilized. So why did a fruit even begin to develop?

    I'm looking forward to enlightenment; this has been bugging me for 5 months!
     

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  2. Daniel Mosquin

    Daniel Mosquin Esteemed Contributor UBC Botanical Garden Forums Administrator Forums Moderator 10 Years

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    The seed contains the embryo--the seed coat is maternal tissue, whereas what is inside is the product of fertilization (or double fertilization in the case of flowering plants). So you can certainly have "vacant"or even partially-developed seeds.

    Fruits in the botanical sense are also maternal tissue. There is a range of triggers for fruit development, including pollination + fertilization, pollination only, fertilization only, and (I suppose the lack of a trigger) no pollination and no fertilization. Post-fertilization is also a factor, as embryos can have development halted for such reasons as mismatches in chromosomes or mutations... and that itself can also affect the hormonal triggers for completing or aborting fruit development.
     
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  3. Gwen Miller

    Gwen Miller Member

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  4. Gwen Miller

    Gwen Miller Member

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    I've found the precise situation that bewildered me, if you're interested. Demonstrated by Lambert of Free Spirit Nursery in Langley. Stumbled across it on Instagram while I was doing some essential Trillium shopping. (Yay! Trip to Langley on Thursday to pick up three!)
     

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