Difference Between C3 Plants vs. C4 Plants

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Main Difference

There are various types of plants found in our ecosystem. Here, we are classifying them into two major types C3 and C4 plants.There is more abundance of C3 plants as compared to the C4 plants. About 85% of plants are C3 plants, and 15% of plants are C4 plants. Main or the key difference between C3 and C4 is that C3 are found in all photosynthetic plants and C4 are found usually in tropical plants. C3 plants don’t have an adaptation of reduction in photorespiration, but C4 plants have a tendency to reduce the rate of photorespiration. C3 plants have a higher rate of photorespiration, whereas C4 plants have a lower rate of photorespiration. For the synthesis of glucose, C3 plants require 12 NADPH molecules and 18 ATP molecules while C4 plants require 12 NADPH molecules and 30 ATP molecules. C3 plants have a single carbon dioxide fixation, and C4 plants have double carbon dioxide fixation in them.

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Comparison Chart

C3 PlantsC4 Plants
Type of PlantsC3 plants are photosynthetic plants.C4 are tropical plants
Population in %About 85% of total plants species are C3.Around 15% of the total plant species are C4.
PhotorespirationThey have a higher rate of photorespiration.They have a lower rate of photorespiration.
PhotosynthesisC3 perform photosynthesis only when stomata are open.C4 can perform photosynthesis even when stomata are closed or open.
Glucose SynthesisC3 plants need 12NADPH and 18ATP for glucose synthesis.C4 plants require 12NADPH and 30ATP.

What are C3 plants?

The plants that have C3 pathway are called C3 plants. C3 plants are referred to be cool or temperate plants. The C3 plant is said to be a normal plant that has a normal rate of photorespiration; these plants don’t have the capability of reducing their rate of photorespiration. About 85% of world plants are C3 plants; these are all photosynthetic plants that have a higher rate of photorespiration. They perform photosynthesis when stomata are open. These plants are overall less efficient in the process of photosynthesis as compared to the C4 plants. Photosynthesis is the food making the process of plants, through which food is made by the plants themselves utilizing light energy. These plants have normal structure of leaves. These plants require about 12 NADPH and 18 ATP for the synthesis of glucose. C3 plants usually have a single fixation of CO2. These plants involve the first enzyme RUBISCO and have a compensation point of CO2 of 30-70PPM. Plants that use the cycle are mesophytic, xerophytic and hydrophytic. C3 plants are well adapted to wet, cooler surrounding. They have an optimum temperature of around 65-75 degree F and soil temperature of 40-45 degree F; their growth starts properly at this temperature. They have no separation in CO2 fixation and Calvin cycle. Some of the prominent examples of C3 plants are wheat, rice, and oats, etc.

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What are C4 plants?

The plants that have C4 pathway are called C4 plants. C4 plants are also referred to be hot or warm seasoned plants. C4 plants have a lower rate of photorespiration, plus these plants have the capability of reducing their rate of photorespiration. About 15% of world plants are C4 plants; these are all tropical plants that have a low rate of photorespiration. They perform photosynthesis even when stomata are either open or close. These plants are overall more efficient in the process of photosynthesis as compared to the C3 plants. These plants have a Kranz anatomy of a leaf. They require about 12 NADPH and 30 ATP for the synthesis of glucose. These plants have a double fixation of CO2. C4 plants involve the first enzyme PEP carboxylase and have a compensation point of CO2 of 10PPM. Plants that use the cycle are mesophytic. C4 plants are well adapted to the warm or hot surrounding. They have an optimum temperature of 90-95 degree F and soil temperature of 60-65 degree F; they grow best at this temperature. They have separation in CO2 fixation and Calvin cycle between mesophyll and bundle sheath cells. Some of the prominent examples of C4 plants are corn, sudangrass, and pearl millet, etc.

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C3 plants vs. C4 plants

  • About 85% of total plants species are C3, and only 15% are C4 plants.
  • C3 plants are photosynthetic plants, whereas C4 are tropical plants.
  • C3 plants are said as cool season plants while C4 plants are said as warm season plants.
  • C3 plants have a high rate of photorespiration whereas C4 have a low rate of photorespiration.
  • C3 plants cannot reduce photorespiration, but C4 plants can reduce it too
  • C3 perform photosynthesis only when stomata are open, but C4 can perform photosynthesis even when stomata are closed.
  • C3 plants need 12NADPH and 18ATP for glucose synthesis while C4 plants need 12NADPH and 30ATP.

Video Explanation

https://www.youtube.com/watch?v=X9TFvjZFj-s