Chapter 5Mineral Nutrition of Plants

1- Water2- Mineral

Know the essential and beneficial plant mineral nutrients and their functions in plants

Learning objectives

Classifying mineral nutrients

• Amount necesserity or presence in plant tissue

• Biochemical function(s) and Metabolic needs

• Mobility within the plant

Essentiality of mineral nutrients

• Essential nutrients:• Absence prevents completion of life cycle• Absence leads to deficiency• Required for some aspect of mineral nutrition

• Beneficial nutrients:• Stimulates growth and development• May be required in some species• Examples: Na, Si,

According to Biochemical functions and Physiological Purposes

Mengel-Kirkby (1987)

1. Group; Plant assimilate these nutrients via biochemical reactions involving oxidation & reduction to form covalent bonds with carbon and create organic compounds;

2. Group; Important for energy storage reactions or in maintaining structural integrity. Found as phosphate, borate, and silica esters- sugar-phosphate

3. Group; Present in plant tissues as either free ions dissolved in plant water or bounded electro-statically to substances as pectic acids in cell wall. Enzyme cofactors and in the regulation of osmotic potentials

4. Group; Has important roles in reactions involving electron transfer (redox)

Out of these many elements, there are many more naturally occurring in soil such as Al, Se and Co involving special functions for certain plants

Biochemical functions of mineral nutrients-1

Biochemical functions of mineral nutrients-2

Biochemical functions of mineral nutrients-3

Nutrient solution can sustain rapid plant growth

Hoagland solutions; contains all of the known mineral elements needed

for rapid plant growth. The concentrations are set at the highest possible levels without producing toxic symptoms or any stress as salinity, alkalinity.

Phosphorus found in soil as 0.06 ppm Hoagland solution 62 ppmBuffering the solution by ammonia (NH4

+) and nitrate (NO3

-). pH maintenance.

Special techniques are used in nutritional

studiesA. Hydrophonic growth system

B. Nutrient film growth system

C. Aeroponic growth system

D. Ebb and flow system

Figure 5.2 Various types of solution culture systems (A,B)

Figure 5.2 Various types of solution culture systems (C,D)

https://www.youtube.com/watch?v=o1QXCnC-2h4

https://www.youtube.com/watch?v=9ZTikdxj8AI

https://www.youtube.com/watch?v=F_WuJ9P1u-k

Mobility in Deficiency

• The location where a deficiency develops reflects the mobility of a nutrient from older leaves to younger.

• Nutrients are redistributed in the phloem

Means that early symptoms of deficiency seen in older leaves

Foliar application

• Uptake through the leaves

• Effective only for phloem-mobile nutrients

• May be more effective than soil application for elements.

• Fe, Zn, Cu and Mn