1. NUTRITION IN PLANTS

2. 1) Nutrients :-
The components of food like carbohydrates, fats, proteins vitamins and minerals are called nutrients.
Nutrients help living organisms :-
i) To build their bodies.
ii) To grow.
iii) To repair the damaged parts of their bodies.
iv) To provide energy to carry out life processes.

3. 2) Nutrition :-
The mode of taking food by an organism and its utilization in the body is called nutrition.
3) Modes of nutrition :- There are two main modes of nutrition in living organisms. They are autotrophic nutrition and heterotrophic nutrition.
i) Autotrophic nutrition :- is nutrition in which organisms can prepare their own food.
Organisms which can prepare their own food are called autotrophs.
ii) Heterotrophic nutrition :- is nutrition in which organisms get their food directly or indirectly from plants.
Organisms which get their food directly or indirectly from plants are called heterotrophs.

4. 4)Photosynthesis - Food making process in plants :-
Photosynthesis is the process by which plants prepare their on food by using sunlight, water, carbon dioxide and chlorophyll.
Photosynthesis take place in the leaves.
i) Sunlight is obtained from the sun.
ii) Water is absorbed by the roots and transported to the leaves.
iii) Carbon dioxide is taken from the air through small pores in the
leaves called stomata.
iv) Chlorophyll are the green pigments present in the leaves.

6. Chlorophyll uses the energy from sunlight to prepare food by using water and carbon dioxide. The food prepared is carbohydrate which is then converted into starch. During photosynthesis oxygen is released.
Equation of photosynthesis :-
Sunlight
Carbon dioxide + Water Carbohydrate + Oxygen
Chlorophyll

7. 5) Synthesis of proteins :-
The soil has some bacteria which convert nitrogen from the air into usable nitrogen in the soil. Farmers also add fertilisers containig nitrogen into the soil. Plants absorb this nitrogen from the soil along with water and other constituents to prepare proteins and fats.

8. 6) Other modes of nutrition in plants :-
i) Parasitic plants :- are plants which do not have chlorophyll and cannot prepare their own food. They get their food from other plants called host . Eg :- Cuscuta ( Amarbel)

9. ii) Insectivorous plants :- are plants which feed on insects
ii) Insectivorous plants :- are plants which feed on insects. Eg:- Pitcher plant. The leaf of the pitcher plant is modified into a pitcher. The end of the pitcher has a lid which can open and close. When an insect enters the pitcher, the lid closes. The insect is then digested by digestive juices inside the pitcher.

10. iii) Saprotrophs :- are plants which do not have chlorophyll and cannot prepare their on food. They get their food from dead and decaying organic matter. Eg :- mushroom, bread mould etc. They produce digestive juice on the dead and decaying organic matter and convert it into a solution and then absorb the nutrients from the solution.

11. iv) Symbiotic relationship :- Some plants live together and share shelter and nutrients. Eg :- lichens. In lichens, an alga and a fungus live together. The fungus provides shelter, water and minerals to the alga. The alga provides food to the fungus which it prepares by photosynthesis.

12. 7) How nutrients are replenished in the soil :-
Plants absorb nutrients from the soil. So the nutrients in the soil decreases. So farmers add manures and fertilisers to the soil to increase the nutrients in the soil.
The bacterium called rhizobium which lives in the roots of leguminous plants like grams, peas, beans etc. converts nitrogen from the air into soluble form in the soil and makes the soil rich in nitrogen. In return the plant provides food and shelter to the bacteria. So they have a symbiotic relationship.

13. Essential plant nutrients
Introduction
A total of only 17 elements are essential for the growth and full development of higher green plants according to the criteria laid down by Arnon and Stout (1939). These criteria are:
A deficiency of an essential nutrient makes it impossible for the plant to complete the vegetative or reproductive stage of its life cycle.
Such deficiency is specific to the element in question and can be prevented or corrected only by supplying this element.
The element is involved directly in the nutrition of the plant quite apart from its possible effects in correcting some unfavourable microbiological or chemical condition of the soil or other culture medium.

14. Essential plant nutrients
Introduction
The essentiality of most micronutrients for higher plants was established between 1922 and 1954.
The essentiality of nickel (Ni) was established in 1987 by Brown et al., although there is no unanimity among the scientists as to whether Ni is essential or beneficial.
However, this list may not be considered as final and it is probable that more elements may prove to be essential in future. The chronology of discoveries of essential nutrient elements is given in Table (see next slide).

15. Essential plant nutrients
Chronology of discoveries of essential nutrient elements for higher plants
Element
Discoverer of Essentiality
Year
Carbon (C)
Hydrogen (H)
Oxygen (O)
Nitrogen (N)
Phosphorus (P)
Potassium (K)
Sulphur (S)
Calcium (Ca)
Magnesium (Mg)
DeSaussure
Ville
von Sachs, Knop
1804
1860
1865
(Glass, 1989; Marschner, 1997)

16. Essential plant nutrients
Chronology of discoveries of essential nutrient elements for higher plants
Element
Discoverer of Essentiality
Year
Iron (Fe)
Manganese (Mn)
Copper (Cu)
Zinc (Zn)
Molybdenum (Mo)
Boron (B)
Chlorine (Cl)
Nickel (Ni)
von Sachs, Knop
McHargue
Lipman and MacKinney
Sommer and Lipman
Arnon and Stout
Warington
Broyer et al.
1860
1922
1931
1926
1938
1923
1954
1987
(Glass, 1989; Marschner, 1997)

17. Essential plant nutrients
Classification of essential plant nutrients

18. Essential plant nutrients
Frame-work nutrient elements
Carbon (C) and oxygen (O) are obtained from the gas CO2, and hydrogen (H) is obtained from water (H2O).
These three elements are required in large quantities for the production of plant constituents such as cellulose or starch.
Hence, many times referred as frame-work elements.
Oxygen, carbon and hydrogen make up 95 percent of plant biomass, and the remaining 5 percent is made up by all other elements.

19. Essential plant nutrients
Macronutrients
Macronutrients are nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), and sulphur (S).
The one or two letter symbol in parentheses is the universal chemical symbol for that nutrient.
N, P, and K are often referred to as primary nutrients and are the most common elements found in commercial fertilizers.
Ca, Mg, and S are referred to as secondary nutrients and are also found in fertilizers and soil amendments.

20. Essential plant nutrients
Micronutrients
Micronutrients include iron (Fe), manganese (Mn), zinc (Zn), boron (B), copper (Cu), chloride (Cl), molybdenum (Mo), and nickel (Ni).
Micronutrients are required in relatively minute quantities and rarely limit plant growth in the environment.
Note: Cobalt (Co), sodium (Na), vanadium (V) and silicon (Si) are sometimes called as beneficial plant nutrients. They are not required by all plants but appear to benefit certain plants. Cobalt is required for nitrogen fixation in legumes. Silicon is found in plant cell walls and appears to produce tougher cells. This increases the resistance of these plants to piercing and sucking insects and decreases the spread of fungal diseases.

21. Essential plant nutrients
Typical concentrations of nutrient elements sufficient for plant growth
Element
Symbol
mg/kg
percent
Relative number of atoms
Nitrogen N
15,000
1.5
1,000,000
Potassium K
10,000
1.0
250,000
Calcium Ca
5,000
0.5
125,000
Magnesium Mg
2,000
0.2
80,000
Phosphorus P
60,000
Sulphur S
1,000
0.1
30,000
(Epstein, 1965; Epstein and Bloom, 2005)