Okay so we've only just touched the surface when it comes to finding out all we want to know about DNA, but hey so far I'm in the dark just as much as you are, but I'm hell bent to find out as much as I can about this invisible fascinating subject. Right I think we ought set out the various influences that go to make up the growth of stem, leaf, flower, petal, early or lateness of that flower, etc etc etc.
Sorry for that - we watched The King & I on a DVD just after Christmas.
As the most important part of the plant is perhaps the flower we'll start there - although of course a flower isn't worth a jot unless it has a good stem to support it.
DNA WITHIN A FLOWER:
It wasn't by chance I picked yellow for the first heading because it's the colour of pollen, and every pollen grain has half of the formula needed to produce the next generation. Even if that generation is totally mixed up by ol' Bumble, but come on we've passed that stage, and we're talking hand pollinating here - aren't we? So what do we know of pollen apart from it being the sperm from the male part of the flower? We know of course that the pollen if placed onto the female reproductive organs through either wind, insects, or in our case by us placing it there, it is enough to form a union. The combination of both male, and female chromosomes eventually form the seeds that produce the next generation of plants.
Now so far I've found out there are eight sets of chromosomes in species dahlias, and possibly twice as many in hybrid dahlias - probably why we see such diverse results in the crosses we make. These chromosomes are responsible for every alteration in each generation. Some we hardly notice - like the shape of the leaves, but others like the shape the petals and hence the shape of the flowers is more noticeable. Even the height of the next generation is adjusted by these scholars the Chromosomes. So far all this has been found out by reading books, and using the Internet. Although I've endeavoured to put my own peculiar slant on it keep you interested.
So it's consult the books time again to find out if I'm right in what I think about chromosomes - just in case I start talking a load of tosh.
According to the author Ethel R Hanauer M.A. who wrote Biology Made Simple which is the reference book I'm using to fathom out the things I don't know about DNA - the chromosomes are thread like bodies within the nucleus. Their function is very important because they pass on the characteristics of one generation to the next. I suppose we should also find out what the nucleus is while we're at it - especially as this vital part holds the chromosomes. There is a nucleus inside every cell, and its job is to tell every thing what to do - it is indeed the governor. Now as we are dealing with two sets of these nucleus - given we are using two varieties - this is where the combined struggle of what the next generation looks like starts, and because we are dealing with the flower this means not only the shape, size, and colour of the petal, but how they in turn sit on the stem to form the flower. What a can of worms we have opened already? So far we are only talking about the colourful part of he plant - its flower, but there is exactly the same process going on in every other part of the plant with cells dividing and expanding at ever stage.
Let's recap - each cell has within it - the nucleus which hold the DNA which governs how the chromosomes react. Fair enough I guess that sentence is pretty clear - but on the chromosomes are molecules of protein called genes, and these are actually responsible for identifying the characteristics of each species. You see although I'm trying to put this information down in its simplest form we are dealing with quite a complex subject, and because we can't see them with the naked eye it makes matters worse. Perhaps a diagram similar to the illustrations in Biology Made Simple would be helpful, by the way it is available on Amazon .
Time to take out my box of paints.
This will give you a good idea of what the various parts of the cell that we're interested in look like. Believe me there is far more to plant cells than their ability to reproduce, but we'll look at those points later. First let's go through the parts we can see.
Starting at the top is the Cell Membrane which is a thin layer that surrounds the cell. It is protected by a rigid layer called the Cell Wall which is I believe responsible for giving the various parts of the plant their shape and rigidity.
The Cytoplast is a jelly like substance inside each cell where all the action takes place.
Next is the Nucleus, and the most important part of the cell - without it nothing else would function. This is the control centre, and contains the very thing we are studying DNA.
Last, but by all means least is the Chloroplast where photosynthesis takes place to make the chlorophyll which the plant can use. During photosynthesis the chlorophyll in the leaves and stem of the plant take in the energy from sunlight in the form of a minute particles called a photons - take my word for it - it's in the book. The photons react by splitting the water in the chlorophyll molecules into hydrogen and oxygen. The hydrogen mixes with carbon dioxide which the plant has absorbed from the air, and makes the sugars, and glucose that the plants needs. We all know the oxygen is released to keep the air we breath sweet. Pretty fantastic eh?
Should anyone who's studying this subject like to correct anything I've written, or indeed add anything please don't hesitate to email me. I'd be more than grateful for your assistance.
Now lets take a look at the whole picture, and the mass of instructions that a dahlia, or any plant will have hidden away in each cell, and they do it all without a computer in sight.