Thinking outside the box again

[noviceveggrower]

Hi, My daughter asked the questions about the fish in the sea. Where are they swimming to? How do they sleep when they have no eyelids etc.
Well at school their new topic is about how things grow and change. They are doing the usual broad bean growing in a plastic tube etc.
So yesterday while we were sorting some seeds out she asked " how do seeds know which way to grow?" Her question related to the fact that pea seeds are round so how do you know which way to plant it. Then if you plant say a broad bean upside down how does it know its upside down and knows how to turn round in the soil?.
Then it was how do bulbs know when to wake up. With little boy have speech problems we explained that the bulbs were asleep and were waiting to wake up. So I said it was all to do with the temperature and a chemical reaction in the bulb. I know I was fluffing for an answer. But she then of course she wanted to know what a chemical reaction was.
I know. She isn't in the same room as the box again.
Oh and does anyone know the correct answers to my wrong ones
Thanks

[Capsid]

The chemicals are called giberellins which stimulate the breakdown of starch into sugars required to power growth. The trigger that breaks seed dormancy are many and varied.

The chemicals that makes roots go down and shoots go up are called auxins, the processes are quite complex.

There is a nice explanation on BBC bitesize

[Kristen]

The seeds don't turn around in the soil, they just germinate, but as they grow they then grow "the right way up". This is due to Gravitropism / Geotropism. As the cells divide, causing the plant to grow, (either at the tip of the stem, or the ends of the roots) Gravitropism causes those new cells in the roots to grown down, in the direction of gravity, and the ones on the stems upwards / away from gravity and/or towards light. Lay a plant on its side and the tip will then start to grow upwards (which appears as though it has turned).

There is a Bamboo which grows "kinks" in its stems. This is because it grows so fast that the balance of the Auxins (which control Gravitropism) on each side of the stem sometimes gets out of whack so, on that day, one side grows faster than the other. Tomorrow the new growth is balanced, so the plant resumes growing vertically again - but the result is the crook-stems.



Growing plants in space is difficult because there is no gravity to make the Auxins differentiate Up from Down.

en.wikipedia.org/wiki/Gravitropism

The breakdown of Starch to sugars, including simple Mono- and Di-saccharides, for fuel for germination is also the process of Malting - e.g. malting Barley to then use the Malt for Beer and Whisky - as the simpler sugars can be converted to alcohol (e.g. by Yeast). Malting is just the act of adding water to (usually) Barley to make it germinate, releasing the enzymes for germination and converting part/most/all of the Starch to simple sugars, and then stopping the germination - e.g. by drying, or even roasting (e.g. for Malt used to make Stout). Some enzymes involved in the process of germination have a flavour associated with them, so in addition to Beer the Malt can be used in confectionery for the benefit of those flavours. Maltesers perhaps?

Dunno the age of the young student, but I know I was brewing beer in an air raid shelter at school before I was 15 so you can either go the Alcohol route in the lesson, or the confectionery one

[noviceveggrower]

The seeds don't turn around in the soil, they just germinate, but as they grow they then grow "the right way up". This is due to Gravitropism / Geotropism. As the cells divide, causing the plant to grow, (either at the tip of the stem, or the ends of the roots) Gravitropism causes those new cells in the roots to grown down, in the direction of gravity, and the ones on the stems upwards / away from gravity and/or towards light. Lay a plant on its side and the tip will then start to grow upwards (which appears as though it has turned).

There is a Bamboo which grows "kinks" in its stems. This is because it grows so fast that the balance of the Auxins (which control Gravitropism) on each side of the stem sometimes gets out of whack so, on that day, one side grows faster than the other. Tomorrow the new growth is balanced, so the plant resumes growing vertically again - but the result is the crook-stems.


Growing plants in space is difficult because there is no gravity to make the Auxins differentiate Up from Down.

en.wikipedia.org/wiki/Gravitropism

The breakdown of Starch to sugars, including simple Mono- and Di-saccharides, for fuel for germination is also the process of Malting - e.g. malting Barley to then use the Malt for Beer and Whisky - as the simpler sugars can be converted to alcohol (e.g. by Yeast). Malting is just the act of adding water to (usually) Barley to make it germinate, releasing the enzymes for germination and converting part/most/all of the Starch to simple sugars, and then stopping the germination - e.g. by drying, or even roasting (e.g. for Malt used to make Stout). Some enzymes involved in the process of germination have a flavour associated with them, so in addition to Beer the Malt can be used in confectionery for the benefit of those flavours. Maltesers perhaps?

Dunno the age of the young student, but I know I was brewing beer in an air raid shelter at school before I was 15 so you can either go the Alcohol route in the lesson, or the confectionery one

Thanks for that. She is only 6 so think we'd have to go down the confectionery route

[Florence Fennel]

Oh dear, I would have said they wake up and look for the sunlight and food to grow big and strong, just like you do. Call me old fashioned, they grow up too fast these days

[noviceveggrower]

Tell me about it. Think she is 6 going on 16 sometimes. Don't think they have a childhood now to much pressure put on them now.

[Florence Fennel]

Make the most of her childhood nvg, you'll wake up one morning and wonder where the years went

[Two_Sheds]

" how do seeds know which way to grow?" ... how do bulbs know when to wake up.

It's down to light, and increasing day length. Not much to do with heat