Question

In an attempt to find out where a growing plant gets its mass, Van Helmont planted a willow seedling in a pot of soil. After five years, the willow weighed 76.8kg, and the soil had lost 0.06kg of weight. Only water had been added to the pot. Which of the following conclusions should Van helmont have drawn?
A. Plants get their mass from water
B. Plants get their mass from water and air
C. Plants get their mass from water and atmospheric $CO_{2}$
D. Plants get all or almost of their mass from a source other than soil

Answer 1

Hint: We have to remember that the Van Helmont, from the Spanish Netherlands, was a chemist, physiologist, and physician. Just after the emergence of iatrochemistry, he worked throughout the years and is often considered the father of pneumatic chemistry. He was the first to realise that gases are isolated from ambient air in kind.

Complete answer: To see if the theory of ancient Greece was right, Van Helmont performed an experiment. He grew a willow tree with a large amount of soil. He found after five years that the willow tree weighed about 74 kg more than it did at the beginning. As the weight of the soil had scarcely increased, Van Helmont argued that plant growth could not only be due to soil minerals.
He thought it was from the water alone that the extra plant material had come. He deduced that the tree's weight gain came solely from water, because the volume of soil was almost the same as it was when he began his experiment (it lost just 57 grams).
The exact response, therefore, is "Plants receive all or nearly all of their mass from a source other than soil".So, the correct answer is “Option D”.

Note:
We have to know that among the earliest exploratory studies, Helmont's experiment on a willow tree was considered. In the history of biology, it was plant nutrition and development and as a landmark. The experiment was published in Ortus Medicinae (1648) only retroactively and may have been influenced by Nicholas of Cusa, who wrote in The statistics experiments on the same theory. Van Helmont subsequently wrote extensively on the subject of digestion.