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Live Births in Plants: The Strange Science of Vivipary · Hydroponics Daily

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  Hello there, welcome back to
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  Hydroponics Daily, your go-to podcast for everything soilless cultivation.
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  I'm your host, Dr. Russell Sharp, and today we're talking about a form of plant
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  propagation that is 100% natural, even though it doesn't look it,
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  but is extremely rare in most plants.
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  There are a few plants that do undertake this form, and it's called vivipari.
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  Vivipari. okay and it's the
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  production of plantlets on the plant before the
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  before normal so the seeds the
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  seeds germinate on the plant so instead
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  of producing fruit with dormant seeds these plants under certain conditions
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  can allow the seeds to germinate while they're still attached the miniature
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  plants are called plantlets or pups and they achieve a larger size being before
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  being thrown out to the environment to survive on their own.
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  So it's a bit like giving birth to live young as opposed to eggs in animals,
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  which is the exception rather than the rule in plants.
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  These small plantlets normally drop onto the ground to begin their life as their own independent plant.
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  Obviously, the advantage of that is that they get a
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  head start on plants that are forming from seed the
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  disadvantage is that they can't go dormant if
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  the conditions aren't correct for them and also
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  they can't be dispersed far from the mother plant whereas a seed let's think
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  about something like a dandelion seed or a maple seed it can travel in the wind
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  for a long distance the plant that doesn't fall far from the plant could be a really rubbish phrase.
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  So, vivipari can currently only be induced in those species where it's known to occur in nature.
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  However, more and more plants are being found to be able to germinate viviparously,
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  and many of them are hydroponic, because that's why I'm talking about it today,
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  and there are some notable examples.
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  There is also false vivipari, and we'll talk about that.
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  So, normally this doesn't happen because the seeds and the fruit tissue particularly
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  contains high levels of the hormone ABA or abscisic acid.
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  But plant scientists normally like to just refer to ABA because it's not just
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  involved in the process of abscission.
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  So ABA is a small molecule that inhibits growth and particularly inhibits germination.
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  And normally this is why the seeds don't germinate when they're in the fruit.
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  That's why when you have, well let's take an example, a pear,
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  the pear seeds that don't germinate inside the fruit, you have to wash them,
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  remove the ABA and dry them and then soak them in water again and that's why they germinate.
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  So scientists have actually been able to produce mutant plants with reduced
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  synthesis of ABA and these mutants often exhibit vivipari. So that's one of the,
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  findings from these low ABA or no ABA plants.
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  These low ABA plants will also be extremely sensitive to stress because ABA is the stress hormone.
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  While it's quite uncommon in flowering plants, the normal fruit and vegetite
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  plants, it is quite common in conifers.
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  So a number of conifer species you'll find that the seeds will germinate inside the cones,
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  especially if they've been exposed to water or laid
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  on the floor for a long time before the seeds have been
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  allowed to be released from the cone
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  and when you find this in a plant that's not particularly
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  common to it it's normally because they've been grown outside in
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  high moisture conditions so we'll
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  talk about one particular example the house plant calanchoe and
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  that's like it's like a really succulent house plant
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  with bright flowers they will produce
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  little plantlets on their leaves as well that's a
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  type of asexual cloning vivipary
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  that's extremely rare and you'll only
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  get it in certain plant species you won't find it on other
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  plants producing these little plantlets onions anything
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  in the onion family you might find little bulbils where
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  there should be flowers i think that's clustered as false vivipary but you'll
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  find it on chives and there's actually a variety called char char chive and
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  on char char chive you get it's very common and that's what you actually purchase
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  it for is the little ornamental baubles and little plantlets on the top it looks
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  cool it looks ornamental.
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  Mangroves are particularly prone to vivipari and you can imagine a mangrove
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  swamp is one of the harshest environments for a plant to grow because of that
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  salt water and the tides and things like this and getting established into the,
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  into the, what's the word, the mud, really, I won't really call it soil,
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  is really difficult for a plant.
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  So to get going on the plant, the mother plant, for some time and then actually
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  be released is actually a big evolutionary advantage in mangroves.
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  There's a couple of other succulents that have got scientific names.
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  Frucaria fetida, doesn't sound nice because it's got fetida in the name,
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  that means it's normally got a horrible smell.
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  We talked about the alliums, what else can we say venous flytrap
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  lots of carnivorous plants produce and viviparous
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  seeds and it's very common so imagine these
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  plants live in again harsh environments and bogs
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  where there's not much nutrients and so to just
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  feed off that mother plant for a number of months is
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  actually quite useful and if
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  you google vivipary there are a number
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  of examples and one of the
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  particular examples is tomatoes
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  seeds that are germinating from the inside the
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  tomato these are normally this will be a a low
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  aba mutant normally that's occurring there you'll also
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  find legal cannabis seeds germinating
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  on mother plants viviparously and this
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  where this has happened i saw one example it
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  was in western sorry eastern australia
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  and up in the northeast of
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  australia we think of australia as being this dry desert-like environment but
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  up in the northeast it's actually a rainforest a jungle and so it's extremely
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  wet and this legal cannabis plant had it's been so wet and moist in in the rainforest
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  the seeds germinated in the flower and so the roots are appearing.
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  Don't know if that's a good thing or a bad thing there might be situations where that is a good thing.
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  If you can think of them, let me know. But certainly, it looks like a very,
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  very strange flower, one of the strangest flowers I've seen.
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  So yeah, the northeast of Australia, one of the places I'd love to go.
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  When I was a child, I used to have the CD-ROM.
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  Can you imagine that CD-ROM of Bushtucker Man, who was a ethnobotanist.
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  And he had these short little video clips. He had a TV program as well.
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  And he'd teach you all about the plants of northeastern Australia in the bush.
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  He was a special force, ex-special forces, or probably was special forces,
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  an SAS, and he would teach all special forces people how to survive in the jungle
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  on the food and things like that. So I found that really interesting.
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  And I always remember this one plant who's like saying, the aborigines used
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  this to induce an abortion when they had an unwanted pregnancy.
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  The women would take the seeds and they'd put it in a bowl of water and the ones that float it,
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  were safe to use. And the ones that sank were poisonous and the ones that floated were safe to use.
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  And then at the end, he said, and this would abort the fetus,
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  but more often than not, you'd end up aborting yourself.
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  I was like, it's like a 12 year old. I was like, what the hell?
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  Yeah. So it was pretty hardcore, this XSAS guy.
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  But yeah, back to the subject at hand, vivipari occurs
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  in northeastern australia because it's
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  so humid and hot so that the illegal cannabis
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  plants love the conditions but if they're not getting mildew because of the
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  high humidity the seeds will germinate another reason to control your humidity
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  if you're growing legal cannabis you might induce unwanted vivipari it's the
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  word of the day it's been hydroponics daily subject,
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  word today if you've had viviparous plants in anything that i have not mentioned
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  then please get in contact with me and i'm more than happy to do a follow-up
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  and shout out in a future episode if you know somebody's had viviparous crops
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  share this episode with them and until tomorrow thank you very much for listening goodbye.