Why do some plants grow in water

  
  
  What is slowing down the growth of plants?
  
Can trees grow to the sky?
 The cells in plants are constantly dividing. One could assume that plants could keep growing. However, this is prevented by the laws of nature:
The example of the largest trees on earth illustrates the limits of growth:
The largest trees in the world are sequoias. They can reach heights of over 110m and a trunk diameter of up to 8m or more.
The question why the trees don't grow into the sky can be answered if you take a closer look at how the water that the plants absolutely need to grow and live actually works:
The tree absorbs the water from the ground through its roots. The water gets higher and higher via a conductive fabric inside the trunk and ends up in the leaves. Here it can then be used for photosynthesis and evaporates. How does the water manage to come up so high?
The water that the roots absorb from the ground ensures that water pressure is created. The pressure pushes the water into the ducts of the conductive tissue. The leaves are constantly consuming water. This creates a negative pressure that attracts the water. In addition to this interplay of overpressure and underpressure, there is also the capillary force: the ducts are so thin that the water is restricted and thus receives even more pressure. Through these three processes, the water can be transported upwards against the gravitational force (force of attraction) of the earth.
This process works until the root pressure and the capillary forces are no longer sufficient to transport the water even higher.
And that it doesn't go any higher is the reason why the trees don't grow into the sky!

The stability of a stem or tree trunk is also not unlimited. The stem or tree trunk would snap off or collapse if a certain mass was exceeded. After reaching a certain height, growth is only possible in width.
   
Plants need "food" to grow
 Plants need water and nutrients from the soil and nitrogen from the air in order to grow and live. Water as a vital component must be available or made available in sufficient quantities. The more and faster plants grow, the more water and nutrients they need. If these substances are missing, a plant cannot grow. It withers and dies.
  
  Do plants die or do they keep living?
  
 Too many plants in one place and rapid growth deprive the soil of available water and nutrients. Larger plants need more than smaller ones. The plants compete with each other and "fight" for food and light. They deprive the smaller plants of their needs. Smaller plants die and thereby disappear. If the nutrients and the water are reduced, deficiency symptoms also occur in larger plants. If not enough fertilizer and water are added to the soil, the large plants also die as a result of the shortage. Plants therefore need a balanced supply of water and nutrients. With a great diversity of species, however, many different plant species find their niche.
   
Causes of plant death
 Many influences by nature and by humans can mean the end of life for plants. Causes are storms, earthquakes, landslides, mudslides, glaciers, avalanches, fires and other natural disasters. Human causes include harvesting, deforestation, clearing and the use of pesticides.
  
   Plants grow under different conditions on our earth
  
The growth of plants in different regions of the world
 Many plants on our earth grow under favorable, others under very extreme conditions. You can adapt. There are even plants that cannot reproduce until they have been exposed to a fire. There are plants in almost all regions of the world.
A series of experiments with plants, e.g. beans in different containers (flower boxes) and the documentation of the measurements in tables provide information about the conditions under which plants thrive particularly well or poorly.
   
The importance of light for plant growth
 

Light is the basic requirement for photosynthesis. It supplies the energy that is essential for the creation of organic matter.

Explanation of photosynthesis:
The plants are made up of cells.
There are chloroplasts in these cells. These are cells that can produce oxygen and grape sugar from sunlight, water and CO2.
So the plant absorbs the energy of the sun, the water and CO2.
Photosynthesis then takes place in the cells. This creates oxygen and glucose.
Plants need glucose in order to grow.
For them, oxygen is for the most part just a "waste material". But since plants also have mitochondria in their cells, which can only survive with oxygen, they also need a little bit of oxygen for themselves.
They release the rest of the oxygen (O2) into the atmosphere, where we can breathe it.

   
© Pedagogical Institute for the German Language Group Bozen 2000 -. Last change: 02.09.2009