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Chapter 10. Mineral nutrition and transport in plants. Soil. Mineral particles Organic matter Water Air Living organisms. Soil – mineral particles. Sand, silt, clay. Soil texture triangle. How is soil texture important to plant growth?. Soil texture and hydraulic properties.
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Chapter 10 Mineral nutrition and transport in plants
Soil • Mineral particles • Organic matter • Water • Air • Living organisms
Soil – mineral particles Sand, silt, clay
How is soil texture important to plant growth? • Soil texture and hydraulic properties
Organic matter • Humus <20% humus = mineral soil >20% humus = organic soil • Provides nutrients, aeration • Increases water holding capacity
Living organisms in soil • Microorganisms • Bacteria, fungi, algae, protozoa, actinomycetes • Insects • Earthworms, beetles, nematodes, ants
How are soil organisms important to plants? • Aerate soil • Become humus • Influence soil pH • Can make soil uninhabitable • Symbiosis with plants
Soil profiles A B • Soil horizons O – organic A – topsoil B – subsoil C – parent material D – bedrock C D
Soils and mineral nutrition • 16 essential nutrients for plant growth • How can essential nutrients be identified?
Nutrient deficiencies potassium zinc iron phosphorus magnesium
Availability of nutrients influences growth and productivity
Plant nutrition • 13 essential mineral nutrients • N,P,K,S,Ca,Mg,Fe,Cl,Mn,B,Zn,Cu,Mo • 3 essential non-mineral nutrients • C,H,O • What makes these nutrients essential?
Mineral nutrients exist as ions • How do plants acquire mineral ions that are bound to clay particles?
Roots produce hydrogen ions as byproducts of respirationCO2 + H2O H2CO3 HCO3- + H+
How does cation exchange affect soil pH? • Raising soil pH with lime Ca(OH)2 + 2H+ Ca2+ + 2H2O
Soil pH and mineral nutrition Different types of plants have different soil pH requirements (truffle link)
Fertilizers • Fertilizer analysis • (N-P-K) • Analysis varies depending on growth objectives
Recreational hydroponics • Home hydroponics systems
Transport in plants • Water and mineral nutrients must be absorbed by the roots and transported throughout the plant • Sugars must be transported from site of production, throughout the plant, and stored
Transport and water potential • Water potential (Ψ) of a cell: Ψcell = Ψp + Ψπ + Ψm p = pressure potential π = solute potential m = matrix potential
Ψp - Pressure potential (turgor) Low Ψp High Ψp
Ψπ- Solute potential • Pure water Ψπ = 0 • All solutions, Ψπ < 0 • As solute concentration increases, Ψcell …
Water movement in plants • Movement from high Ψcell to low Ψcell • Occurs in the xylem Early thoughts on water transport • Capillary action
higher ψ higher ψ Transpiration creates tension lower ψ lower ψ cohesion lower ψ higher ψ highest ψ Tension-cohesion theory higher ψ • Water is drawn up the plant by transpiration of water from stomata low ψ
Importance of stomata • Regulate transpiration rate • Controls rate of water uptake • Water required for photosynthesis • Water required to maintain turgor pressure • Controls nutrient uptake • Regulate gas exchange • CO2 required for photosynthesis
Ψ and transpiration rate • In terms of ψ, can you explain how transpiration rate is influenced by: • Atmospheric humidity? • Wind? • Air temperature? • Light intensity?
Transpiration and photosynthesis • The dilemma of a hot, sunny day? Good for photosynthesis, but… Bad for water loss
1M 10-50mM Phloem transport • Pressure-flow hypothesis
Water transport and Christianity • Plants and water are used throughout the Bible to give us a picture of a spiritual reality
Revelation 22: 1-3 1 Then the angel showed me the river of the water of life, as clear as crystal, flowing from the throne of God and of the Lamb 2 down the middle of the great street of the city. On each side of the river stood the tree of life, bearing twelve crops of fruit, yielding its fruit every month. And the leaves of the tree are for the healing of the nations. 3 No longer will there be any curse. How can a tree stand on both sides of a river? What does this image suggest?
John 7: 37-39 37 On the last and greatest day of the Feast, Jesus stood and said in a loud voice, "If anyone is thirsty, let him come to me and drink. 38 Whoever believes in me, as the Scripture has said, streams of living water will flow from within him." 39 By this he meant the Spirit, whom those who believed in him were later to receive. Up to that time the Spirit had not been given, since Jesus had not yet been glorified. • Water is the Holy Spirit given to those that believe • There is nothing you have to do to obtain this water except believe it has been given to you
John 15: 5-6 5 "I am the vine; you are the branches. If a man remains in me and I in him, he will bear much fruit; apart from me you can do nothing. 6 If anyone does not remain in me, he is like a branch that is thrown away and withers; • We are part of the same living organism as Jesus, depicted here as a plant • What causes a plant to wilt? • The Spirit flowing from the throne of God and Jesus (Rev. 22) keeps us alive (Romans – but the Spirit…life) • Fruit is mostly water
Galatians 5: 22-23 22 But the fruit of the Spirit is love, joy, peace, patience, kindness, goodness, faithfulness, 23 gentleness and self-control. Against such things there is no law. Proverbs 11: 30 The fruit of the righteous is a tree of life
John 7: 38 "Whoever believes in me, as the Scripture has said, streams of living water will flow from within him." • Jesus is the vine, we are the branches, branches have leaves, leaves have? Rev 22:2 On each side of the river stood the tree of life, bearing twelve crops of fruit, yielding its fruit every month. And the leaves of the tree are for the healing of the nations.