Answer:
One of the earliest experiments to determine the answer to this question was performed by van Helmont in the 1600s. He planted a 2 kg willow tree in a sealed pot that contained 90 kg of dried soil. He watered the pot with rainwater. After five years, he found that the willow weighed 77 kg while only 60 grams of soil were missing. He concluded that the added weight of the plant arose out of the water. [1]
In light of our knowledge of photosynthesis, we know that the weight added is due to both atmospheric carbon dioxide and water. What's interesting is that John Woodward discovered that more than water contributed to the mass of the plant in 1699.[2] About 100 years later, in 1796, Senbier showed that carbon dioxide was utilized by plants in photosynthesis. In 1797, de Saussure demonstrated that both carbon dioxide and water, along with light, are required for plants to gain mass. [3], [4]
So in the end, we (mostly) add mass via
nCO2+nH2O+light→(CH2O)n+nO2
(CH2O)n can be utilized in many forms. For example, cellulose is a polysaccharide formed from many units of glucose C6H12O6 linked together.
Photosynthesis does account for most of the mass that is added within a plant. Of course, there are other important nutrients that plants need. One of the most important is magnesium, which is at the centre of the chlorophyll molecule. These other nutrients come from the soil.
Step-by-step explanation:
≤hope it helps≥