Page 3 - LN-PHOTOSYNTHESIS IN PLANTS

those bubbles did not take place.
He did this by placing the experimental set-up once in the dark and once in the
sunlight. The bubbles that he observed were of oxygen and showed that only green
parts of plants could release oxygen.
Conclusion
He thus, concluded that sunlight is essential for the plant that purifies the foul air
produced by burning candles or by breathing of animals.
Julius Von Sachs
He with his experiments in 1854 provided evidence that glucose is produced when
plants grow, which is usually stored as starch. He later showed that a green
substance, i. e., chlorophyll is found to be located in special bodies called chloroplast
in plant cells.
Conclusion
He came to the conclusion that green parts are the place in the plants where
production of glucose takes place and the same is stored in the form of starch.
The Engelmann (1843-1909)
He determined the action spectrum of photosynthesis by performing the interesting
experiment with the help of a green alga, Cladophora. He splits light into its spectral
components by using prism. He then illuminated the alga placed in a suspension of
aerobic bacteria.
The bacteria were used to detect the sites of O 2 evolution. On doing so, he noticed
that the accumulation of bacteria was mainly in the region of the blue and red light of
the split spectrum.
Conclusion
By the work done by him at first, action spectrum of photosynthesis was thus
described, which roughly resembles the absorption spectra of chlorophyll-a and b.
Therefore, the key features of the process of photosynthesis were known by the
middle of the nineteenth century, which detailed that plants acquire light energy
harvested from sunlight for the formation of carbohydrates (food) from CO 2 and
water.
The empirical equation thus, determined the totalprocess of photosynthesisfor
organisms that evolves oxygen is understood as

Cornelius Van Neil (1897-1985)
He was a microbiologist, who made a significant contribution on the basis of his
studies of purple and green bacteria (photosynthetic bacteria) in understanding the
photosynthesis. He demonstrated that during the process of photosynthesis, the
hydrogen from a suitable oxidisable compound transferred, which reduces CO 2 to
carbohydrates in the presence of sunlight.

With the help of this, he reaches to the conclusion that, photosynthesis is a light
dependent phenomenon.
Further, he states that in photosynthetic bacteriaH2S acts as a hydrogen donor,
which gets oxidised to sulphur, i.e., they do not evolve O 2 during the process of
photosynthesis. While in case of green plants H 2O acts as a hydrogen donor, which