Inventors and Scientific Discoveries

In 1930 C.B Van Niel proved that, sulphur bacteria use $H _{2}S$ and $CO _{2}$ to synthesize carbohydrates as follows:

$6CO _{2}+12H _{2}S\rightarrow C _{6}H _{12}O _{6}+6H _{2}O+12S$

This led Van Niel to the postulation that in green plants, water $(H _{2}O)$ is utilized in place of $H _{2}S$ and $O _{2}$ is evolved in place of sulphur. He indicated that water is electron donor in photosynthesis.

$6CO _{2}+12H _{2}O\rightarrow C _{6}H _{12}O _{6}+6H _{2}O+6O _{2}$

Photosynthesis is a process by which green plants manufacture their food with the help of carbon dioxide and water in the presence of sunlight. It was discovered by Jan Ingenhousz. Through his experiments, he showed that sunlight is essential for the plant process that helps to somehow purify the air fouled by the breathing mouse and the burning candle in Priestley's bell jar experiment. In another experiment with an aquatic plant (Hydrilla), he showed that in bright sunlight, small bubbles were formed around the green parts of the plant while in dark, no bubbles were formed. He identified those bubbles to be of oxygen. Thus, the correct answer is option C.

Photosynthesis is a process by which green plants manufacture their food with the help of carbon dioxide and water in the presence of sunlight. It was discovered by Jan Ingenhousz. Through his experiments, he showed that sunlight is essential for the plant process that helps to somehow purify the air fouled by the breathing mouse and the burning candle in Priestley's bell jar experiment. In another experiment with an aquatic plant (Hydrilla), he showed that in bright sunlight, small bubbles were formed around the green parts of the plant while in dark, no bubbles were formed. Thus, the correct answer is option A.

• Symplast was first given by Eduard Tang in 1879 who discovered plasmodesmata.
• In 1880, Hanstein coined the term symplast.
• But these both terms are given together by Munch in the year 1930.

Melvin Calvin was the professor of chemistry. He was awarded the nobel prize for chemistry for the discovery of various pathways of photosynthesis. 3-phosphoglyceric acid as first $CO _{2}$ fixation product in algal photosynthesis was discovered by Calvin. He used radioactive $^{14}C$ in algal photosynthetic studies. This led to the discovery that the first $CO _{2}$ fixation product was a three-carbon organic acid. He also helped to mark out the complete biosynthetic pathway, hence it is named as Calvin Cycle. The first stable product identified was 3-phosphoglyceric acid (PGA), hence it is named as $C _{3}$ pathway. Calvin cycle occurs in all photosynthetic plants whether they have $C _{3}$ or $C _{4}$ pathway.

Photosynthesis is a process by which green plants manufacture their food with the help of carbon dioxide and water in the presence of sunlight. It was discovered by Jan Ingenhousz. Through his experiments, he showed that sunlight is essential for the plant process that helps to somehow purify the air fouled by the breathing mouse and the burning candle in Priestley's bell jar experiment. In another experiment with an aquatic plant (Hydrilla), he showed that in bright sunlight, small bubbles were formed around the green parts of the plant while in dark, no bubbles were formed. He identified those bubbles to be of oxygen. Thus, the correct answer is option B.

A) Stephen Hales is called the father of plant physiology for his extensive research on photosynthesis.
B) Joseph Priestley showed that animals exhale carbon dioxide (impure air) and plants give out oxygen (pure air).
C) Ingenhousz showed that light is essential for photosynthesis.
D) Von Helmont proved that plants require minerals from the soil for photosynthesis.
So the correct answer is 'Priestley'.

Engelman discovered the action spectrum of photosynthesis in 1833. He found that bacteria accumulated in the region of blue and red light of split spectrum. He thus discovered the effect of the different wavelength of the light on photosynthesis and at that time he discovered the first action spectrum of photosynthesis.
So, the correct option is B.

The process of photophosphorylation was discovered by Arnon. He used the term assimilatory to refer ATP and $NADP$. Photophosphorylation is the process in which light energy is converted into chemical energy through the production of ATP. The process of reduction of $NADP$ into $NADP + H^{+}$ may be denoted as electron transport system (ETS). 

Peter Dennis Mitchell, was a British biochemist who was awarded the 1978 Nobel Prize for Chemistry for his discovery of the chemiosmotic mechanism of ATP synthesis. 

A) Photosynthesis was partially discovered by Jan Baptista van Helmont, a Belgian chemist, physiologist and physician.
B) Stephen Hales proved that plants require light for photosynthesis.
C) Joseph Priestley revealed the essential role of air in the growth of green plants.
So the correct answer is 'Stephen Hales'.

Julius Robert Mayer made his claim in his The Organic Motion in its Relation to Metabolism which was published in 1845. In this publication, he wrote: "The plants take in one form of power, light and produce another power, chemical difference." He used the term ‘power’ for energy and ‘chemical difference’ for chemical energy. He, therefore, made it clear that plants do not only produce organic matter but also provide the energy which sustains life. Consequently, his finding has made further enlightenment on photosynthesis.

Plant physiology is a subdiscipline of botany concerned with the functioning, or physiology, of plants.