Topic 5

Mineral Elements Required in Plant Nutrition

Nutrient Deficiency Symptoms,

International Plant Nutition Institute Photo contest

Recognizing nutrient deficiency symptoms

turfgrass nutrient deficiency symptoms

1. Nitrogen (N)

- used in larger quantities than any other mineral nutrient

- most frequently deficient for normal growth of non-legumes

a. Forms taken up by plants

NO₃^- NH₄⁺

b. Function in plants

- It is part of the amino acids which make up proteins

- It is part of the chlorophyll molecule

c. N Deficiency symptoms turf

 

- plants become stunted and/or become yellow on the older leaves

- N is mobile in the plant so new leaves may remain green

- excess N may delay maturity

- cause excess growth and little fruiting on melons and tomatoes. Excessive succulence may make a plant more susceptible to disease or insect attack.

2. Phosphorus (P)

a. Forms taken up by the plant

H₂PO₄^- - primary orthophosphate

H₂PO₄⁼ - secondary orthophosphate

b. Functions in plants

- a part of the protein molecule

- necessary for transfer of energy during metabolic processes (ATP)

- hastens maturity, promotes good root development, improves drouth and cold tolerance, improves seedling vigor, important in seed and fruit formation.

c. P,deficiency symptoms

- overall reduction in growth, stunting

- dark green color - purple cast in corn , lower leaves first because P is mobile.

- delay in maturity

- failure of seed to form

3. Potassium (K)

It is used in larger amounts than any other element except N. May have "luxury consumption" plants take up more than is needed. K is not a part of any structural component of the plant. Located in the cell sap as an inorganic salt.

a. Forms taken up by plants

K⁺

b. Functions in plants

1. it is a catalyst in many reactions; carbohydrate, starch and N metabolism

2. activation of enzymes involved in photosynthesis, and protein and carbohydrate metabolism

3. adjustment of stomatal movement and water relations

4. helps disease resistance

5. increases quality of fruits and vegetables

c. K deficiency symptoms

- tips and margins of leaves turn brown. K is mobile so this occurs first on lower leaves.

- weakening of straw in grain crops (lodging)

K is important in preventing non-protein N from accumulating in plants. When this occurs in forages it may be injurious to animals

4. Calcium

a. Forms taken up by plants

Ca⁺⁺

b. Functions in plants

- calcium pectate gives strength to cell walls

- needed for peg development in peanuts

- plant root and tip elongation

c. Ca deficiency symptoms

- Ca is immobile so new growth is affected

- failure of terminal buds to develop

-symptoms are not usually seen under field conditions because other problems caused by acidity of soil will generally become limiting factors before Ca. That is, liming prevents Ca deficiency from occurring.

-blossom end rot of tomatoes is an exception to this generalization

5. Magnesium

a. Forms taken up by plants

Mg⁺⁺

b. Functions in plants

a part of the chlorophyll molecule - essential in photosynthesis

- related to phosphorus metabolism

- large quantities found in seed

c. Mg deficiency symptoms

 

- Mg is mobile so symptoms occur first in old leaves.

- interveinal chlorosis. A whitish or yellowish striping effect on grasses.

Tobacco - referred to as sand drowning.

6. Sulfur (S)

a. Forms taken up by plants

sulfate some SO₄^-2

(Sulfur dioxide through leaves).

b. Functions in plants

- a constituent of 3 of the 21 amino acids which form protein cystine, cysteine, methionine

- present in the organic compounds that give the characteristic odors of onion, garlic, and mustard.

c. S deficiency symptoms

- uniformly chlorotic plants which are stunted and spindly. Similar to N deficiency symptoms. It is less mobile than N so deficiency may be more apparent on younger leaves.

7. Manganese (Mn)

a. Forms taken up by plants

Mn⁺⁺, Mn⁺⁺⁺

-Can be absorbed through the leaves. required in small quantities - large amounts are toxic (acid soils)

b. Functions in plants

-activation of enzyme systems

-chlorophyll synthesis

c. Mn deficiency symptoms

- Mn is immobile - The upper leaves develop yellow streaks.

8. Iron

a. Forms taken up by plants

Fe⁺⁺ (ferrous form) Fe⁺⁺⁺ (ferric form)

can be taken up by the leaves

b. Functions in plants

- a catalyst in the production of chlorophyll

- enzyme systems

c. Fe deficiency symptoms

- occur on high pH soils or certain plants

- centipede, azaleas. Immobile so deficiency symptoms occur on young leaves.Interveinal chlorosis. Leaves may turn completely white

9. Copper

a. Forms taken up by plants

Cu⁺² can be absorbed through leaves. Very toxic if too much applied.

b. Functions in plants

- copper is a catalyst in chlorophyll formation

c. Cu deficiency symptoms

- immobile so upper leaves affected - corn youngest leaves are yellow and stunted

- vegetables - plants wilt and develop a bluish green cast.

10. Zinc (Zn)

a. Forms taken up by plants

Zn⁺⁺⁺ can be taken up through leaves. Toxic except in small   quantities.

b. Functions in plants

activator of enzyme systems

c. Zn deficiency symptoms

- occurs on younger leaves (immobile)

- interveinal chlorosis followed by reduction in rate of shoot growth and shortening of internodes (rosetting)

11. Boron

a. Forms taken up by plants

- H₃BO₃ can be taken up through leaves

- can be very toxic if applied to some crops at rates not harmful to others. Deficiency occurs frequently on alfalfa. Rates applied to alfalfa may be toxic to small grains, peas and beans.

b. Functions in plants

- translocation of sugars across membranes

- germination of pollen grains and growth of pollen tubes

c. B deficiency symptoms

B deficiency in Peanuts

Immobile upper leaves affected. Growth of terminal bud stops

Alfalfa - rosetting or bushy appearance in top of plant.

Corn - barren plants

Peanuts - hollow heart

Apples, grapes, pears, walnuts are commonly affected.

12. Molybdenum

-Mo Required in smallest amounts of any mineral nutrient. Excess may be toxic to grazing animals.

a. Forms taken up by plants

MoO₄⁼

b. Functions in plants

- it is needed for conversion of NO₃^- to NH₄⁺ in the plant

- required by rhizobia for N fixation in the nodules of legumes

c. deficiency symptoms

Mo deficiency in cauliflower

- interveinal chlorosis

- with legumes it appears as N deficiency (that's what it is)

 

13. Chloride Cl

a. Forms taken up by plants

Cl^-

b. Functions in plants

- photosynthetic reactions

c. Chloride deficiency symptoms

c.

- Reduced root growth in nutrient cultures. None observed in field.

- Excessive quantities has a detrimental effect on quality of potatoes and tobacco storage quality of potatoes reduced. Smoking quality of tobacco lowered.

14. Ni deficiency symptoms

15. Other elements

Cobalt (Co)

- needed in small quantities by rhizobia for fixation of N in association with legumes. 8 oz/acre on clover gave response essential in formation of vitamin B-12.

Vanadium (V)

- Shown to be essential for a green algae

- not shown to be essential for higher plants but growth increases were shown with asparagus, rice,lettuce, barley, corn.

Function not known.

Sodium (Na)

Functions - may be essential for carbohydrate metabolism in some plants. May substitute for potassium

Plants that benefit are cabbage, celery, kale, sugar beet, mustard, swiss chard, radish, table beet, turnip

Silicon

- increased growth of rice in nutrient cultures. Function unknown.

Rice, cucumbers, barley

Summary

N - synthesis of proteins and part of chlorophyll molecule

P - energy transfer

K - carbohydrate metabolism, water relations

Mg - chlorophyll molecule

S - proteins

Ca - strength of cell wall

Micronutrients - enzyme activation

Plant nutrient deficiencies and toxicities

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