4. Nutrition in Plants
We can differentiate several phases in plant nutrition:
a) Absorption:
Plants take water and mineral salts from the soil through their roots. The mixture of these substances is called raw sap.
b) Transport:
Raw sap ascends from roots to leaves through the conductive vessels of the xylem. Once it is transformed in elaborate sap, it is distributed to every cell through the conductive vessels of the phloem.
c) Transpiration:
The excess of water that plants absorb through their roots is expelled into the atmosphere through the stomata, in a process called transpiration. This process helps raw sap to ascend.
d) Photosynthesis:
Plants use the energy from sunlight and inorganic matter (carbon dioxide and water) to produce organic matter (glucose) through this chemical process. All green parts of the plant perform photosynthesis.
This process takes place within the chloroplasts that contain chlorophyll. This pigment can catch the energy of sunlight and transform it in chemical energy. Then this energy is used to produce organic substances from the inorganic ones.
Raw sap provides water for photosynthesis and carbon dioxide is absorbed by the stomas.
During the process, besides glucose, oxygen is produced and plants expel it into the atmosphere.
We can represent the reaction of photosynthesis as:
In this way, raw sap is changed into elaborated sap that is a mixture of water and glucose.
e) Respiration:
As all living beings, plants need energy to carry out vital functions. To obtain it, every cell burns organic matter in their mitochondria. This process is called cellular respiration and produces water and carbon dioxide besides energy. To do it, cell needs oxygen that is absorbed by the stomas.
The reaction of respiration is:
Plants perform respiration during the day and during the night, but only can perform photosynthesis while they have sunlight.
READING ACTIVITIES
After reading the text, copy and answer the following questions into your notebook:
Remember: you must make complete sentences.
4.1. The following pictures represent the gaseous exchange produced
in a leaf in different moments of the day: dawn, noon and night.
Which of them correspond to every one?
a. Do plants perform respiration during the day?
Do they do it during the night?
b. Do they perform photosynthesis during the day?
Do they do it during the night?
4.2. Order the steps of plants nutrition. Copy them in the correct order:
4.3. Indicate the differences between:
a. Raw sap - Elaborate sap
b. Xylem – Phloem
c. Respiration - Photosynthesis
4.4. Listen and indicate what term is described:
a. Photosynthesis
b. Respiration
c. Xylem
d. Phloem
e. Raw sap
f. Elaborated sap
g. Chlorophyll
h. Stomata
Now,
check
your
answers!
LISTENING ACTIVITIES
Download this worksheet
and complete it,
while you listen this audio.
SPEAKING ACTIVITIES
Now, in turns with your partner,
answer the questions in the worksheet.