Chapter 13: Photosynthesis in Higher Plants

Any part of the plant which has green in colour can photosynthesize. So the statement is wrong. Examples include Chlorophyll roots of Trap and Timisoara and photosynthesis. The stem is changed into a fleshy green structure in Opuntia and the leaves are altered in spines to reduce transpiration. Photosynthesis occurs in the stem of these plants. Opuntia’s modified stem is named phylloclade. In most of the plants, sepals are green and they do perform photosynthesis.

(a) Outer side of thylakoid membrane

(b) Inner side of thylakoid membrane

(c) Stroma of chloroplast

(d) Chloroplast

(e) Chloroplast

The most abundant pigment in plants is chlorophyll a. This pigment demonstrates the optimal efficiency between blue and red-light wavelengths. Pigments are capable of absorbing light with a certain wavelength so they absorb various colours of light. Pigments show optimal efficiency between the blue and red light. This is due to the chlorophyll and also can be due to the accessory pigments. This means that in the range of red and blue light the rate of photosynthesis is higher.

In the blue and region there is maximum absorption by the chlorophyll and also shows a higher rate of photosynthesis. Thus we can say that the chief pigment associated with photosynthesis is chlorophyll a.

The diagram peak is of 400nm wavelength which is equal to blue and peaks again between 600 and 700nm which is of red. Therefore shows that the spectrum of action and absorption overlaps. The black line shows the photosynthesis action spectrum, while the blue line displays the spectrum of absorption.

C4 plants are superior to C3 due to the following conditions

a) They have a characteristic leaf anatomy

b) They withstand higher temperatures.

c) They show response to high light intensities

d) They have greater productivity of biomass

a. The action spectrum indicates the rate of photosynthesis. The measurement is oxygen release the oxygen releases on the y-axis and the wavelength on the x-axis can be compared to the action spectrum.

b) The absorption of various wavelengths for a particular pigment can be done by the processing, such as chlorophyll-a, or chlorophyll b, or any other pigment.

Water division: sunlight energy is used to divide the water molecule into hydrogen ion and

NADP⁺ to NADPH is used for the extra electron released after the split.

Oxygen release: after the division of the water molecule oxygen discharges into the stomach.

High-energy intermediate formation (ATP and NADPH): two energy-rich combinations ATP and NADPH are formed at the end of an electricity reaction.

cyclic photophosphorylation is possible here. Photophosphorylation is the synthesis of ATP from ADP and inorganic phosphate in the presence of light.

It acts as both carboxylase and oxygenase, so it is referred to as RUBP carboxylase–Oxygenase.

Rubisco binds CO₂ to 3PGA in C3 plants. In C3 plants, Rubisco is binding with O₂ in a process known photorespiration to generate phosphoglycerate and phosphoglycerate. Photo vacuum reduces carbon attachment in C3 plants.

The vascular bundles in leaves contain a sheath of large cells. In particular, chloroplast impregnates several layers of cells around the bundle cell. These cell thick walls cannot be exchanged for gasses. The sheath is without intercellular space. C4 plants over C4 plants are securely fastened with the bundle sheath. It helps to increase the level of carbon dioxide in the leaves. We know that it is competitive to bind Rubisco to CO₂ and oxygen. C4 plants lack photorespiration. C4 plants are superior to C3 due to the following conditions

a) They have a characteristic leaf anatomy

b) They withstand high temperatures.

c) They show response to high light intensities