Naked Science Forum
Life Sciences => Plant Sciences, Zoology & Evolution => Topic started by: neilep on 14/11/2023 13:34:19
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How do seeds know which way to grow ? Do they reorientate themselves if they have been planted upside down ?
whajafink ?
Thanks
Incognito Sheep !
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Some bulbs reorient themselves. Seeds generally seem to be less polarised, but some, particularly wild oats, actually roll around, propelled by the twisting of the awn, until they fall onto a crevice where they can germinate. "Planting" is of course not a natural process: seeds fall on the bare soil and taking root is a matter of chance unless some friendly bird or mammal has buried them. Once germination has begun, up and down are determined by gravity and light, and things can get very confused in orbit.
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A lot of seeds I've watched seem to germinate out of some predetermined end, which might be the 'down' side. Both stem and root (stem first) seem to emerge from the same end. The stem part curls upward due to gravity, and yes, plants pretty much rely on that.
I've not seen bulbs reorient themselves but do not assert that it doesn't happen. Some bulbs I've planted come with instructions as to which end to point up, but the typical daffydills and crocuses (croci?) seem to do just fine if you just throw em in the hole.
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Quite correct, Halc, about both ends of a sprouting seed arising from the same location. Most of a seed is stored nutrition and the actual embryo is quite small. The embryo uses the stored nutrients to form the first leaves and the initial root.
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Is that the same for spuds I have cut with multiple eyes? Is it the light and chlorophyll that cause the upward facing eyes to become foliage and the lower eyes to become roots growing down and spreading out away from the surface? seems that the position of the eyes matters to a spud...LOL..