This document explores how photosynthesis products contribute to the formation of reserves in plants and their mobilization for various functions, highlighting the chemical nature of these reserves in different plant organs.
Extract
[...] The experiment therefore shows a certain diversity in the tested organs. We will perform 3 tests to distinguish the chemical nature of the reserves and whose characteristics are presented below: Tests performed Expected result Specific to? Iodized water The coloration changes from yellow to brown-violet ? starch (complex sugar" Rouge Soudan" Red 'droplets' appear." ? of lipids (fatty substances) Biuret Reagent A blue violet coloration appears ? of proteins" Table comparing the characteristics of tests performed" Question Communicate the results in your preferred format The photos of the results obtained for the different positive results are shown below: Thus, we can deduce from these results: - a brown-violet staining (iodine water test) appears in the potato. [...]
[...] Fats, or lipids, are gathered in droplets stored in oleoplasts, which are specialized plastids for storing lipids. Oleoplasts can be found in the fruits of plants as lipids are a very good source of energy. They can also be found in other parts of the plants such as flowers or certain leaves (from which essential oils and perfumes can be made). Proteins are mainly present within the vacuole of plant cells. If there are many, they gather and crystallize in the form of grains called aleurone grains. They are found in seeds, particularly protein-rich seeds. [...]
[...] - droplets appear with a light red staining (sudan red test). We deduce that the walnut kernel contains lipids. The other tests are . negative/positive to be completed. In conclusion, we note that the plant reserves have a different nature depending on the organs studied, and that all families of nutrients can be found. Question Specify the location of its reserves Let's recall that the fruit is an organ resulting from the transformation of a flower and contains a seed, the organ that protects and contains the plant embryo, and that the tuber is an underground reserve organ. [...]
