During the daytime plants need light to live, in order to be able to produce sugars and carbohydrates as well as oxygen. However at night they can't produce these. In order to survive this period without light, they breathe, in a way similar to human beings--by using oxygen and carbohydrates. This is called respiration. It is the opposite of photosynthesis.
The term "breath" is improper, instead of this term you could use the right term "respiration".
As every living organism, plants, during the process of respiration, take in the oxygen and release carbon dioxide.
Also, during photosynthesis, plants absorb carbon dioxide and emit oxygen,photosynthesis being the process used to form the nutritious substances necessary for growth and development of plants, and it took place in the chloroplast only in the presence of light. Chloroplasts contain a green pigment called chlorophyll, which absorbs light energy from the sun.
From water and minerals (crude sap arrived in leaf ) in the presence of carbon dioxide in leaf, organic substances (sap drawn) and oxygen are formed. Starch is the organic matter from the sap drawn, resulting from photosynthesis.
Oxygen is removed from the leaf through stoma.
Knowing all the above, the conclusion is that during the night, the process of photosynthesis, which changes CO2 into O2 to feed themselves, cannot be held, because of the lack of light, so the plants have to use O2 for carrying the electrons.
this is a proces of equlibrium status of the nature ,during day times plants excrete carbon di oxide and human beings respire oxygen .during night plants not getting light and they change their action and take oxygen for respiration .this is a interrelated process of nature
During the daytime the plants need light to live,in order to be able to produce sugars and carbohydrates as well as oxygen. However at night they cant produce these.In order to survive this period with out light,they breath, in a way similar to human beings-by using oxygen and carbohydrates. This is called rspiration.It is the opposite of photosynthesis which occur in plants.