I am currently studying biology in Grade 11 at High School. I grew Brassica rapa from seed with a control of just tap water and two treatments with different sugar solutions under 24 hour light.
The control plants (no sugar) flourished and grew to a height of 10.5 cm over 4 weeks. However, the plants receiving sugar solution perished before reaching 1 cm in height.
I was aware that the plants would not be able to utilize the sugar solution as energy, but I was not expecting them to die.
Can anyone who reads my Mum’s blog tell me what affect the sugar might have had on these plants?
Thankyou, Caroline Marohasy
Jennifer Marohasy BSc PhD is a critical thinker with expertise in the scientific method.
Maybe fungal attack due to the fungus being stimulated by the sugar. Did the seedlings fall over from an apparent weakness near ground level?
Hi Caroline,
You did not mention the media used to germinate the seeds, or the concentration of the sugar water. The type of media is important.
In a garden or field situation a sugar water mix can stimulate some microbiological activity
Perhaps there was too much sugar in the water. Possibly the sugar water acted on plant material (nitrogen) and produced a yeast substance. Did the dead plants and/or the media smell? You could check the pH of each media to see if there has been a difference in acidity.
Maybe you could run another test with a sterile control and differing concentrations of sugar water checking and recording the pH levels throughout.
Osmotic pressure would be one component, a high concentration of sugar will tend to draw water from the plant tissues stopping cellular activity,
Salt can act in much the same way.
Too much pressure for the little roots to bear I suspect …
i think it likely that your plant did not possess the necessary enzymes to process the sucrose which is not one of its usual foods, into glucose, which is the fundamental form of sugar which most plants and animals use.
To understand this, you need to know that glucose molecules can get joined up in lots of ways, and depending on exactly how the joinings are arranged, different sugars are produced. In your own digestive system, enzymes, which are very like tiny machines, take complex sugars to pieces, and so produce glucose, which goes into the bloodstream.
But there are some sugars in the natural world for which your body does not have the necessary enzymes to metabolise. These sugars are called glycosides, and are poisonous to us, because although they are made up of glucose units so that the body starts trying to deal with them as though it could cope, the body’s systems cannot finish the process, which ends up causing microantomical systems to become jammed.
I think that the same thing probably happened to your plants.
Sugar is used in canned fruit and vegetables as preservative.
Preservatives inhibit bacterial activity, and like salted meat, food immersed in sugar rich fluids tend not to decompose.
Those of us who eat food rich in sugar should find that regulartity is an issue, (high sugar content kills the gut bacteria, hence resulting in constipation).
Like water, sugar in small quantities is useful, in large amounts problematical.
Thankyou so much to everyone who has posted… All of the possibilities have been thought provoking and i am writing up the assignment now.
Sugar is not a food. Sugar is a drug.
And just like any drug,…you can take it, but it will kill you over time.
Nothing that eat(have sugar in it) sugar stays alive for long. Many things(people, animals) do take sugar products and live for a little time.
Over the ages, is has come to be known that sugar kills. But people like it.
When people like something, even if it kills, they will take it and make all type of excuse to use it.
Don’t believe me…
Try going without it for a few days.
No fruits, no rice, no potatos, no honey, no sugar.
Welcome to the drug world.
cool!!
i’m kinda doing a science project like this too
except mine is trying on different types of water
and sugar water was one of mine
^ ^
Very interesting, my projevt is most likely this exact thing. This is a good resours and will help me alot.
Thats really interesting, i did a report similar, but i used gatorade and my plant flourished. Anyone know why that is?