PLANT PHYSIOLOGY

Az Agrármérnöki MSc szak tananyagfejlesztése

TÁMOP-4.1.2-08/1/A-2009-0010

Essential nutrientsNutrient deficiencies

Overview

1. Special techniques are used in nutritional studies

2. Essential nutrients

3. Mineral defficiencies

4. Soil, roots, and microbes

1. Special techniques are used in nutritional studies

1.1. Essential elements can be studied in plants grown under experimental conditions

1.2. The absence of certain elements reveals data about essentiality

1.3. Nutrient solutions containing only inorganic salts have been used in nutritional studies

Source: Taiz L., Zeiger E. (2010): Plant Physiology. p. 111.

Hydroponic growth system: plants are grown in nutrient solution fully saturated with oxygen

Source: Taiz L., Zeiger E. (2010): Plant Physiology. p. 111.

Nutrient film technique

Source: Taiz L., Zeiger E. (2010): Plant Physiology. p. 111.

Aeroponics: nutrient solution is sprayed on roots

Source: Taiz L., Zeiger E. (2010): Plant Physiology. p. 111.

Ebb-and-flow system: roots are covered periodically with nutrient solution

2. Essential nutrients

2.1. An essential element is defined as:

- one that is intrinsic component in the structure or metabolism- whose absence causes several abnormalities in plant growth, development, or reproduction

2.2. They are classified according to their relative concentrations in plant tissues: macronutrients or micronutrients

Source: Taiz L., Zeiger E. (2010): Plant Physiology. p. 108.

3. Mineral defficiencies

3.1. Analysis of plant tissues reveals mineral deficiencies

3.2. Some essential elements can be recycled from older to younger leaves, others are relatively immobile

3.2. Inadequate supply of an essential element is manifested by characteristic deficiency symptoms

Source: Taiz L., Zeiger E. (2010): Plant Physiology. p. 117.

Relationship between yield (or growth) and the nutrient content of the plant tissue

Source: Taiz L., Zeiger E. (2010): Plant Physiology. p. 113.

3. Mineral defficiencies

3.3. They can be grouped as:

Group 1: Deficiencies in mineral nutrients that are part of carbon compounds (N, S)

Group 2: Deficiencies in mineral nutrients that are important in energy storage or structural integrity (P, Si, B)

Group 3: Deficiencies in mineral nutrients that remain in ionic form (K, Ca, Mg, Cl, Mn, Na)

Group 4: Deficiencies in mineral nutrients that are involved in redox reactions (Fe, Zn, Cu, Ni, Mo)

Deficiency symptoms of nitrogen that is a constituent of many critical macromolecules

Source: Taiz L., Zeiger E. (2010): Plant Physiology. Webmaterial, http://5e.plantphys.net

Deficiency symptoms of phosphorus that is part of the nucleic acid backbone and has a central function in intermediary

Source: http://www.ipmimages.org/browse/subimages.cfm?sub=766

Deficiency symptoms of potassium that activates enzymes and functions in osmoregulation

Source: Taiz L., Zeiger E. (2010): Plant Physiology. Webmaterial, http://5e.plantphys.net

Deficiency symptoms of calcium that is important in cell division, cell adhesion, and as a second messenger

Source: http://www.ipmimages.org/browse/subimages.cfm?sub=766

Deficiency symptoms of magnesium that is a constituent of the chlorophyll molecule and an important regulator of enzyme reaction

Source: http://www.ipmimages.org/browse/subimages.cfm?sub=766

Deficiency symptoms of iron that is required for chlorophyll synthesis and electron transfer reactions

Source: Taiz L., Zeiger E. (2010): Plant Physiology. Webmaterial, http://5e.plantphys.net

Deficiency symptoms of zinc that is an activator of numerous enzymes

Source: http://www.ipmimages.org/browse/subimages.cfm?sub=766

4. Soil, roots, and microbes

4.1. Negatively charged soil particles affect the adsorption of mineral nutrients

4.2. Soil pH affects nutrient availability

4.3. Excess mineral ions in the soil limit plant growth

4.4. To obtain nutrients from soil, plants develop extensive root system

4.5. Nutrient availability influences root growth

Source: Taiz L., Zeiger E. (2010): Plant Physiology. p. 120.

The principle of cation exchange on the surface of a soil particle

Source: Taiz L., Zeiger E. (2010): Plant Physiology. p. 118.

Influence of soil pH on the availability of nutrient elements in organic soils

Source: Taiz L., Zeiger E. (2010): Plant Physiology. p. 121.

Fibrous root systems of wheat (a monocot)

Source: Taiz L., Zeiger E. (2010): Plant Physiology. p. 124.

Root biomass as a function of extractable soil NH4+ and NO3

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4. Soil, roots, and microbes

4.6. Mycorrhizal fungi facilitate nutrient uptake by roots

4.7. The fine hyphea of micorrhizae extend to reach of roots into the surrounding soil

4.8. In return, plants provide carbohydrates to the mycorrhizae

4.9. Symbiotic nitrogen fixation

Source: Taiz L., Zeiger E. (2010): Plant Physiology. p. 125.

Root infected with ectotrophic mycorrhizal fungi

Source: Taiz L., Zeiger E. (2010): Plant Physiology. p. 126.

Association of vesicular-arbuscular mycorrhizal fungi with a section of a plant root

Source: Taiz L., Zeiger E. (2010): Plant Physiology. p. 352.

Root nodules on a common bean (Phaseolus vulgaris)

Source: Taiz L., Zeiger E. (2010): Plant Physiology. p. 356.

The infection process during nodule organogenesis that contains nitrogen fixing bacteria

SummaryPlants are autotrophic organisms capable of using the energy from sunlight to synthesize all their components from carbon dioxide, water, and mineral elements. Certain visual symptoms are diagnostic for deficiencies in specific nutrients in higher plants. The size of soil particles and the cation exchange capacity of the soil determine the extent to which a soil provides a reservoir for water and nutrients. To obtain nutrients from the soil, plants develop extensive root systems. Plant roots often form associations with mycorrhizal fungi. The fine hyphae of mycorrhizae extend the reach of roots into the surrounding soil and facilitate the acquisition of mineral elements.

Questions

• What does a plant need to grow from seed and complete its life cycle?

• What is an essential element? How many have been identified?

• What is a mineral deficiency? How can a mineral deficiency be recognized?

• How can farmers benefit from nutrient analysis?• What is the importance of micorrhizal fungi?

THANK YOU FOR YOUR ATTENTION

Next lecture:Nutrient uptakeSolute transport

• Compiled by:Prof. Vince ÖrdögDr. Zoltán Molnár