Plant, disease, defence, bark, thorns, hair, cellulose, metabolites, genetic modification, aspirin.
A plant has evolved to be able to withstand certain diseases, which they have to as a result of the environment they live in. So, how do they survive in all the weather and rush of pathogens and diseases that are in the air?
There are several physical defences that a plant may have, including:
There are several chemical defences a plant has that allows for it to defend itself. Firstly, there are metabolites*1 such as hydrocarbon isoprene, which is a volatile gas that is emitted when photosynthesis occurs. This coats the plant and prevents damage happening. This in turn prevents any pathogens attacking the plants.
Another chemical that plants have are essential oils. These are the smell a flower produces, or that the plant itself produces, and can act as a toxin toward insects. Mint plants (like Mentha viridis - spearmint) and chrysanthemums produce pyrethrins, which acts like neurotoxins for insects, and are also the basis of some insecticides, which effectively kill off insects.
Because blackcurrant plants were banned in the USA due to them increasing risk of passing on disease in the early 1900s, many Americans do not know what the flavour of blackcurrant is like, unless they have bought products from other countries with it in (such as Ribena).
The following still is from a video on transpiration and translocation, with the following details:
Please click on the image to view the video.
Back in the time before modern medicine, medicines were mainly plant based. To relieve a headache nowadays, you would probably use paracetamol or ibuprofen. But back then (around the 1800s), people would use Aspirin.
This was originally made from a plant called White Willow (Salix alba). From the bark in all Salix species, Aspirin is derived from salicin, which is a compound. People used to chew the bark of the tree for pain relief, before being harvested or replicated for use in medicines.
Not only that, there were other uses for the Aspirin. It was used to treat diarrhoea, help reduce inflammation in joints, and for sore throats. It could also stop wounds from bleeding.
Today, Aspirin is still used, but it is synthetically made, and is also not used as often as the likes of paracetamol or ibuprofen.
Test yourself with these exam-style questions. Try not to cheat by opening the anwers first...
Chemical. The toxins produced by the plant are passed on to the animal that attempts to consume it.
