Factors that Affect the Growth in Duckweed
For healthy growth plants need several substances. Three important
mineral ions that can only be obtained from the soil through their
roots are nitrates, phosphates and potassium. Nitrates are essential
for making amino acids and for the 'synthesis' of proteins. Phosphates
are essential as they have an important role in reactions involved in
photosynthesis and respiration. Potassium is also important as it
helps the enzymes involved in photosynthesis and respiration to work.
The three main minerals are needed in fairly large amounts, but other
elements are required in much smaller amounts. Iron and magnesium are
the most important as they are needed to make chlorophyll.
Without photosynthesis, along with minerals, plant growth wouldn't
take place. Photosynthesis produces glucose for 'food' and takes place
in the leaves of all green plants. Glucose is combined with nitrates
(collected from the soil) to make amino acids, which are then made
into proteins. Protein amino acid contains carbon, hydrogen, oxygen
and nitrogen. Along with potassium, phosphorus and sulphur make up the
important substances that travel through the roots and up the stem.
Photosynthesis needs carbon dioxide, water, light and chlorophyll to
continue the process. Without iron and magnesium chlorophyll couldn't
be made and therefore the plant would die.
Diffusion takes place in the leaves, through the stomata. The
membranes allow substances in and out as particles from an area of
high concentration move to an area of low concentration. This takes
place in the example of NO4. There are excess amounts in the leaf and
so it diffuses into the air, as there is less of it in the air
The more nitrogen present in the soil means that there is more protein
for the plant, which therefore makes the plant grow bigger, along with
photosynthesis. I am going to investigate whether Baby Bio, a
fertiliser containing NPK, helps the duckweed increase in growth. I am
using the type Lemma minor, which will absorb the NPK through its
To investigate the effect of Baby Bio on plant growth.
Once duckweed reaches a certain size it divides. The products of
photosynthesis, such as glucose, can be joined with amino acids to
make proteins such as NPK. The phosphorus in NPK enables plants to
make ATP (adensosine tri phosphate). If there is no phosphorus then
ATP will not be present and therefore the plant will die. These
chemicals are transported through the xylem vessels to wherever it is
needed. The duckweed absorbs nitrates (NO3) and phosphates (PO4)
through its roots, as they cannot take them from the air. They are
both soluble in water.
Too much protein also kills...