Plant Physiology  

What is Plant Physiology

A society grows great when old men plant trees whose shade they know they shall never sit in. 

— Greek Proverb

Physiology is the branch of science that deals with the functional aspects of a living organism at the molecular and cellular level. Plant physiology deals with all those events that are vital for the sustenance of a plant. Therefore, plant physiology is the applied field of plant anatomy and plant morphology. Since you have familiarised yourself with the conceptual understanding of the structural organization in plants, this chapter would provide you with a vast and open field to apply those concepts.

 

From the perspective of NEET biology syllabus, plant physiology is the fourth unit in the NCERT textbook of class 11. It is one of those fascinating and interesting chapters that not only build the interest of the students but is also helpful in gaining the marks. Having said that, a through read-up of the concepts of plant physiology would be helpful in securing marks as this chapter holds an approximate of 8% weightage in NEET exam. The stress of scoring is laid here owing to the fact that the concepts of this chapter are easily comprehensible. 

Now as you have understood the essentiality of the chapter plant physiology, let us understand the various topics covered under this chapter and methodology to prepare the same for NEET exam.

 

Topics of Plant Physiology

The topics of plant physiology given by the official syllabus of NEET exam are clearly demarcated under separate chapters in NCERT textbook. As the NCERT textbooks are the foundation of NEET exam and are a must-read to grasp upon the concepts, we shall go by those chapters mentioned in NCERT textbook for class 11.

 

Osmosis

 

Notes on Plant Physiology

1. Transport in Plants: As described earlier, plant physiology is the study of life-sustaining functions and as plants do not show locomotion, it is of utmost importance to understand how are they taking up various nutrient and water from the surrounding. Therefore, the chapter transport in plant deals with the ascent of sap and translocation of food. As you are already familiar with the complex tissues of xylem and phloem, you will appreciate the functioning of the same in this chapter. You will also realise the importance of water for the plants. It can be equated with blood in animals! The following sub-topics need to be studied with attention:

a) Means of transport: diffusion and its types; osmosis.
b) Plant-water relations: water potential, solute potential, matrix potential, plasmolysis, tonicity of solutions, Imbibition.
c) Long-distance transport in plants: translocation, absorption of water by roots (you will have to revise the anatomical details of the root).
d) Water Movement up a Plant: root pressure, transpiration pull, cohesion-adhesion theory.
e) Phloem Transport: Flow From Source To Sink

Hence, the topics of this chapter need a brush-up on the concepts of plant anatomy before proceeding.

 

2. Mineral Nutrition: The topics of plant physiology in this chapter are somewhat based on chapter biomolecules. Herein, you will understand the macronutrients and micronutrients required for the proper functioning of the plant system. The focus is laid on the inorganic mineral nutrition obtained from the soil and atmosphere. Hence, there will also be the concepts of nutrient cycles, namely nitrogen cycle, oxygen cycle, phosphorus cycle and the water cycle. This chapter also deals with the study of deficiency disorders in plants when mineral nutrition are not supplied as per the need. Nonetheless, the topics of this chapter can be summarised under the following heads:

  • Method to Study the Mineral Requirements of Plants: a detailed description of hydroponics.
  • Essential Mineral Elements: Criteria for the essentiality of the minerals, the role of macro and micronutrients, deficiency symptoms of essential elements, the toxicity of micronutrients.
  • Mechanism of Absorption of Elements: Bulk-flow hypothesis.
  • Translocation of Solutes
  • Soil as a Reservoir of Essential Elements
  • Metabolism of Nitrogen: nitrogen cycle, nitrogen fixation and nodule formation in leguminous plants.

 

 Mineral Nutrition

 

3. Photosynthesis in Higher Plants: It is one of those topics of plant physiology that intrigue the brains of both the teachers and students! Based on the concepts of biochemistry, the topic photosynthesis is highly recommended for proper reading because it offers a variety of questions. Let us understand the flow of photosynthesis as mentioned in the NCERT along with the additional concepts required for NEET preparation:

  • Brief description of the historical aspects of understanding photosynthesis, such as Priestley’s Experiment.
  • Site of photosynthesis - detailed analysis of chloroplast, structure, and types of chlorophyll molecules, action and absorption spectra of chlorophyll.
  • Phases of photosynthesis - events of light reaction and dark reaction, electron transport, splitting of water, cyclic and non-cyclic photophosphorylation, chemiosmotic hypothesis.
  • The utility of ATP and NADPH
  • The Calvin cycle, C4 pathway, CAM pathway.
  • Photorespiration
  • Factors affecting photosynthesis.

While preparing the photosynthesis, never indulge in mugging up the concepts. Reason being, the mugged up concepts can never be used to answer the practical questions. Hence, it is advised to read the NCERT thoroughly and then refer to the additional sources for building the clarity of the concepts. This would prove to be significant the day you will appear for the NEET exam!

Photosynthesis in Higher Plants

 

4. Respiration in Plants: The topics of respiration in plants are conceptually at par with the topics of photosynthesis. The respiration in plants also involves the biochemical pathways. Additionally, the concepts of this chapter would be appliable in human physiology too. Hence, you will keep the understanding-of-the-concept mode on even for this chapter! Let us have a glance at the topics from the NCERT textbook as well as from the NEET syllabus:

  • The concept of respiration and breathing, how do plants breathe?
  • Aerobic and anaerobic respiration
  • Glycolysis, fermentation
  • TCA cycle and electron transport chain, the structure of mitochondria
  • Oxidative phosphorylation
  • The respiratory balance sheet
  • Respiratory quotient

After reading the chapter respiration in plants, correlate the electron transport chain that operates in chloroplast to the one that operates in mitochondria. This will help in solving compare and contrast types of questions.

 

5. Plant Growth and Development: The topics of this chapter are equivalent to the nervous system of animals. You will understand the plant hormones and their roles in regulating as well as coordinating various developmental aspects of plants. The significance of light in the growth of the plant will also be the topic of focus. After reading this chapter, you will be able to:

  • Define and characterize the growth in plants
  • Understand the difference between differentiation, dedifferentiation and
  • redifferentiation
  • Define and characterise the plant growth regulators or plant hormones
  • Know about the physiological effects of auxins, gibberellins, cytokinins, ethylene, and abscisic acid
  • Know about the physiology of seed dormancy 
  • Know about the physiology of vernalization 
  • Know about the physiology of photoperiodism, long-day plants, short-day plants and day-neutral plants.

 

Indole-3-acetic acid

 

Tips for Plant Physiology

  • Start building up the basics from the NCERT textbook. Diagrams and equations mentioned in the NCERT textbook are directly asked in the NEET exam.
  • Solve as many questions as you can.
  • Photosynthesis and respiration need to be covered with a lot of attention and conceptual build-up.
  • Be regular in revising the concepts. The biochemistry portion tends to slip out of memory when left untouched for a considerable period!
  • Tabularise the plant hormones, their functions, and effects to have a comparative study. This will come in handy while solving questions.
  • Analyze the pattern from previous years’ papers and set your goal accordingly. 
  • Lastly, keep revising.

 

Books for Plant Physiology

  • The NCERT textbook for class 11
  • A Textbook of CBSE Biology for Class 11 by Sarita Aggarwal
  • Trueman’s Elementary Biology Volume 1

 

Biology Units-wise Notes for Medical Exams

Units No.

Units Name

Unit 1

Diversity in Living World

Unit 2

Structural Organisation in Animals and Plants

Unit 3

Cell Structure and Function

Unit 5

Human Physiology

Unit 6

Reproduction

Unit 7

Genetics and Evolution 

Unit 8

Biology and Human Welfare

Unit 9

Biotechnology and Its Applications 

Unit 10

Ecology and Environment 

Topics from Plant Physiology

  • Cell to cell transport-Diffusion, facilitated diffusion, active transport; Plant water relations Imbibition, water potential, osmosis, plasmolysis ( NEET, AIIMS MBBS, JIPMER MBBS, AP EAMCET Pharmacy, TS EAMCET Pharmacy, KVPY SA, KVPY SB/SX ) (42 concepts)
  • Long distance transport of water Absorption, apoplast, symplast, transpiration pull, root pressure and guttation ( NEET, AIIMS MBBS, JIPMER MBBS, AP EAMCET Pharmacy, TS EAMCET Pharmacy, KVPY SA, KVPY SB/SX ) (23 concepts)
  • Transpiration-Opening and closing of stomata ( NEET, AIIMS MBBS, JIPMER MBBS, AP EAMCET Pharmacy, TS EAMCET Pharmacy, KVPY SA, KVPY SB/SX ) (9 concepts)
  • Uptake and translocation of mineral nutrients-Transport of food, phloem transport ( NEET, AIIMS MBBS, JIPMER MBBS, AP EAMCET Pharmacy, TS EAMCET Pharmacy, KVPY SA, KVPY SB/SX ) (2 concepts)
  • Mass flow hypothesis ( NEET, AIIMS MBBS, JIPMER MBBS, AP EAMCET Pharmacy, TS EAMCET Pharmacy, KVPY SA, KVPY SB/SX ) (4 concepts)
  • Mineral nutrition: Essential minerals, macro and micronutrients and their role ( NEET, AIIMS MBBS, JIPMER MBBS, AP EAMCET Pharmacy, TS EAMCET Pharmacy, KVPY SA, KVPY SB/SX ) (11 concepts)
  • Deficiency symptoms ( NEET, AIIMS MBBS, JIPMER MBBS, AP EAMCET Pharmacy, TS EAMCET Pharmacy, KVPY SA, KVPY SB/SX ) (7 concepts)
  • Elementary idea of Hydroponics as a method to study mineral nutrition ( NEET, AIIMS MBBS, JIPMER MBBS, AP EAMCET Pharmacy, TS EAMCET Pharmacy, KVPY SA, KVPY SB/SX ) (1 concepts)
  • Nitrogen metabolism-Nitrogen cycle, biological nitrogen fixation ( NEET, AIIMS MBBS, JIPMER MBBS, AP EAMCET Pharmacy, TS EAMCET Pharmacy, KVPY SA, KVPY SB/SX ) (15 concepts)
  • Photosynthesis: Photosynthesis as a means of Autotrophic nutrition ( NEET, AIIMS MBBS, JIPMER MBBS, AP EAMCET Pharmacy, TS EAMCET Pharmacy, KVPY SA, KVPY SB/SX ) (15 concepts)
  • Site of photosynthesis take place ( NEET, AIIMS MBBS, JIPMER MBBS, AP EAMCET Pharmacy, TS EAMCET Pharmacy, KVPY SA, KVPY SB/SX ) (2 concepts)
  • pigments involved in Photosynthesis (Elementary idea) ( NEET, AIIMS MBBS, JIPMER MBBS, AP EAMCET Pharmacy, TS EAMCET Pharmacy, KVPY SA, KVPY SB/SX ) (7 concepts)
  • Photochemical and biosynthetic phases of photosynthesis ( NEET, AIIMS MBBS, JIPMER MBBS, AP EAMCET Pharmacy, TS EAMCET Pharmacy, KVPY SA, KVPY SB/SX ) (13 concepts)
  • Cyclic and non cyclic and photophosphorylation ( NEET, AIIMS MBBS, JIPMER MBBS, AP EAMCET Pharmacy, TS EAMCET Pharmacy, KVPY SA, KVPY SB/SX ) (6 concepts)
  • Chemiosmotic hypothesis ( NEET, AIIMS MBBS, JIPMER MBBS, AP EAMCET Pharmacy, TS EAMCET Pharmacy, KVPY SA, KVPY SB/SX ) (1 concepts)
  • Photorespiration C3 and C4 pathways ( NEET, AIIMS MBBS, JIPMER MBBS, AP EAMCET Pharmacy, TS EAMCET Pharmacy, KVPY SA, KVPY SB/SX ) (4 concepts)
  • Factors affecting photosynthesis ( NEET, AIIMS MBBS, JIPMER MBBS, AP EAMCET Pharmacy, TS EAMCET Pharmacy, KVPY SA, KVPY SB/SX ) (6 concepts)
  • Respiration: Exchange gases ( NEET, AIIMS MBBS, JIPMER MBBS, AP EAMCET Pharmacy, TS EAMCET Pharmacy, KVPY SA, KVPY SB/SX ) (2 concepts)
  • Cellular respiration-glycolysis, fermentation (anaerobic), TCA cycle and electron transport system (aerobic) ( NEET, AIIMS MBBS, JIPMER MBBS, AP EAMCET Pharmacy, TS EAMCET Pharmacy, KVPY SA, KVPY SB/SX ) (12 concepts)
  • Energy relations-Number of ATP molecules generated ( NEET, AIIMS MBBS, JIPMER MBBS, AP EAMCET Pharmacy, TS EAMCET Pharmacy, KVPY SA, KVPY SB/SX ) (2 concepts)
  • Amphibolic pathways ( NEET, AIIMS MBBS, JIPMER MBBS, AP EAMCET Pharmacy, TS EAMCET Pharmacy, KVPY SA, KVPY SB/SX ) (1 concepts)
  • Respiratory quotient ( NEET, AIIMS MBBS, JIPMER MBBS, AP EAMCET Pharmacy, TS EAMCET Pharmacy, KVPY SA, KVPY SB/SX ) (2 concepts)
  • Plant growth and development: Seed germination ( NEET, AIIMS MBBS, JIPMER MBBS, AP EAMCET Pharmacy, TS EAMCET Pharmacy, KVPY SA, KVPY SB/SX ) (4 concepts)
  • Phases of Plant growth and plant growth rate ( NEET, AIIMS MBBS, JIPMER MBBS, AP EAMCET Pharmacy, TS EAMCET Pharmacy, KVPY SA, KVPY SB/SX ) (7 concepts)
  • Sequence of developmental process in a plant cell ( NEET, AIIMS MBBS, JIPMER MBBS, AP EAMCET Pharmacy, TS EAMCET Pharmacy, KVPY SA, KVPY SB/SX ) (1 concepts)
  • Growth regulators-auxin, gibberellin, cytokinin, ethylene, ABA ( NEET, AIIMS MBBS, JIPMER MBBS, AP EAMCET Pharmacy, TS EAMCET Pharmacy, KVPY SA, KVPY SB/SX ) (11 concepts)
  • Seed dormancy ( NEET, AIIMS MBBS, JIPMER MBBS, AP EAMCET Pharmacy, TS EAMCET Pharmacy, KVPY SA, KVPY SB/SX ) (1 concepts)
  • Vernalisation ( NEET, AIIMS MBBS, JIPMER MBBS, AP EAMCET Pharmacy, TS EAMCET Pharmacy, KVPY SA, KVPY SB/SX ) (2 concepts)
  • Photoperiodism ( NEET, AIIMS MBBS, JIPMER MBBS, AP EAMCET Pharmacy, TS EAMCET Pharmacy, KVPY SA, KVPY SB/SX ) (8 concepts)
  • Transport in Plants ( NEET, AIIMS MBBS, JIPMER MBBS, AP EAMCET Pharmacy, TS EAMCET Pharmacy, KVPY SA, KVPY SB/SX ) (35 concepts)
  • Mineral Nutrition ( NEET, AIIMS MBBS, JIPMER MBBS, AP EAMCET Pharmacy, TS EAMCET Pharmacy, KVPY SA, KVPY SB/SX ) (16 concepts)
  • Photosynthesis ( NEET, AIIMS MBBS, JIPMER MBBS, AP EAMCET Pharmacy, TS EAMCET Pharmacy, KVPY SA, KVPY SB/SX ) (27 concepts)
  • Respiration in Plants ( NEET, AIIMS MBBS, JIPMER MBBS, AP EAMCET Pharmacy, TS EAMCET Pharmacy, KVPY SA, KVPY SB/SX ) (22 concepts)
  • Plant Growth and Development ( NEET, AIIMS MBBS, JIPMER MBBS, AP EAMCET Pharmacy, TS EAMCET Pharmacy, KVPY SA, KVPY SB/SX ) (33 concepts)

Important Books for Plant Physiology

  • Plant Physiology Book
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