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Nutrition and Transport in Plants
Chapter 26
2Nutrition and TNutrition and Transport in Plaransport in Plantsnts
OutlineOutline
Essential Inorganic NutrientsEssential Inorganic NutrientsSoil FormationSoil Formation
Soil ProfilesSoil Profiles
Soil ErosionSoil Erosion
Water & Mineral UptakeWater & Mineral Uptake
Transport MechanismsTransport MechanismsWaterWater
Organic NutrientsOrganic Nutrients
3Nutrition and TNutrition and Transport in Plaransport in Plantsnts
Plant Nutrition and SoilPlant Nutrition and SoilEssential Inorganic NutrientsEssential Inorganic Nutrients
About 95% of a plant’s dry weight is About 95% of a plant’s dry weight is carbon, hydrogen, and oxygencarbon, hydrogen, and oxygen
Primary nutrients are carbon dioxide Primary nutrients are carbon dioxide and waterand water
Essential nutrients have identifiable Essential nutrients have identifiable role, and a deficiency causes a plant role, and a deficiency causes a plant to dieto die
MacronutrientsMacronutrients
MicronutrientsMicronutrients
4Overview of Plant Nutrition
5Nutrient Deficiencies
6Nutrition and TNutrition and Transport in Plaransport in Plantsnts
Soil FormationSoil Formation
Soil formation begins with weathering Soil formation begins with weathering of rockof rock
Organisms also play an important roleOrganisms also play an important role
Lichens and MossesLichens and Mosses
Humus begins to accumulateHumus begins to accumulate
Under ideal conditions, a centimeter Under ideal conditions, a centimeter of soil may develop within 15 yearsof soil may develop within 15 years
7Nutrition and TNutrition and Transport in Plaransport in Plantsnts
Nutritional Function of SoilNutritional Function of Soil
Soil is a mixture of:Soil is a mixture of:Soil particlesSoil particlesDecaying organic materialDecaying organic materialLiving organismsLiving organismsAir, andAir, andWaterWater
Roots take up oxygen from air spacesRoots take up oxygen from air spacesSoil particles consist primarily ofSoil particles consist primarily of
SandSandClayClaySiltSilt
8Absorbing Minerals
9Nutrition and TNutrition and Transport in Plaransport in Plantsnts
Soil ProfilesSoil Profiles
Soil profile is a vertical section from Soil profile is a vertical section from ground surface to unaltered rock ground surface to unaltered rock belowbelow
Parallel layers - HorizonsParallel layers - Horizons
A (topsoil) - Litter and humusA (topsoil) - Litter and humus
B (subsoil) - Inorganic nutrientsB (subsoil) - Inorganic nutrients
C (weathered rock)C (weathered rock)
Because parent material and climate Because parent material and climate differ, soil profile varies according to differ, soil profile varies according to particular ecosystemparticular ecosystem
10Simplified Soil Profile
11Nutrition and TNutrition and Transport in Plaransport in Plantsnts
Soil ErosionSoil Erosion
Soil erosion occurs when water or Soil erosion occurs when water or wind carry soil away to a new wind carry soil away to a new locationlocation
Worldwide, removes about 25 billion Worldwide, removes about 25 billion tons of topsoil annuallytons of topsoil annually
DeforestationDeforestation
DesertificationDesertification
Agricultural contaminantsAgricultural contaminants
12Nutrition and TNutrition and Transport in Plaransport in Plantsnts
Adaptation of Roots for Mineral Adaptation of Roots for Mineral UptakeUptake
Important Symbiotic RelationshipsImportant Symbiotic Relationships
RhizobiumRhizobium bacteria fix atmospheric bacteria fix atmospheric nitrogennitrogen
Live in root nodulesLive in root nodules
Mycorrhizal association between fungi Mycorrhizal association between fungi and plant rootsand plant roots
EctomycorrhizasEctomycorrhizas
EndomycorrhizasEndomycorrhizas
13Water and Mineral Uptake
14Root Nodules
15Mycorrhizae
16Spanish Moss
17Nutrition and TNutrition and Transport in Plaransport in Plantsnts
Transport Mechanisms in PlantsTransport Mechanisms in Plants
Transported in vascular tissuesTransported in vascular tissues
Xylem transports water Xylem transports water
Two types of conducting cellsTwo types of conducting cells
TracheidsTracheids
Vessel ElementsVessel Elements
Water flows passively from an area of Water flows passively from an area of higher water potential to an area of higher water potential to an area of lower water potentiallower water potential
18Plant Transport System
19 Conducting Cells of Xylem
20Nutrition and TNutrition and Transport in Plaransport in Plantsnts
Transport Mechanisms in PlantsTransport Mechanisms in Plants
Transported in vascular tissues, Transported in vascular tissues, cont.cont.
Phloem transports organic materialsPhloem transports organic materials
Conducting cells are sieve-tube Conducting cells are sieve-tube membersmembers
Have companion cells to provide Have companion cells to provide proteinsproteins
End walls are sieve platesEnd walls are sieve plates
Plasmodesmata extend through sieve Plasmodesmata extend through sieve platesplates
21Nutrition and TNutrition and Transport in Plaransport in Plantsnts
Water TransportWater Transport
Water entering roots creates a Water entering roots creates a positive pressure (root pressure)positive pressure (root pressure)
Pushes xylem sap upwardPushes xylem sap upward
May be responsible for guttationMay be responsible for guttation
Water forced out vein endings along Water forced out vein endings along edges of leavesedges of leaves
22 Guttatio
n
23Nutrition and TNutrition and Transport in Plaransport in Plantsnts
Cohesion-Tension ModelCohesion-Tension ModelCohesion-tension model of xylem Cohesion-tension model of xylem transport suggests a passive xylem transport suggests a passive xylem transporttransport
Water molecules tend to cling togetherWater molecules tend to cling together
Polarity of water allows interaction with Polarity of water allows interaction with molecules of vessel wallsmolecules of vessel walls
Water column moves passively upward Water column moves passively upward due to transpirationdue to transpiration
Column must be continuousColumn must be continuous
Waxy cuticle prevents water lossWaxy cuticle prevents water loss
24 Cohesion-tension Model of
Xylem Transport
25Nutrition and TNutrition and Transport in Plaransport in Plantsnts
Opening and Closing of StomataOpening and Closing of Stomata
Each stoma in leaf epidermis is Each stoma in leaf epidermis is bordered by guard cellsbordered by guard cells
Increased turgor pressure in guard Increased turgor pressure in guard cells opens stomacells opens stoma
Caused by active transport of K+ into Caused by active transport of K+ into guard cellsguard cells
26 Opening and Closing of Stomata
27Nutrition and TNutrition and Transport in Plaransport in Plantsnts
Organic Nutrient TransportOrganic Nutrient Transport
Role of PhloemRole of Phloem
Phloem transports sugarPhloem transports sugar
Girdling of tree below the level of Girdling of tree below the level of leaves causes bark to swell just above leaves causes bark to swell just above the cutthe cut
Sugar accumulates in the swollen Sugar accumulates in the swollen tissuetissue
28Acquiring Phloem Sap
29Nutrition and TNutrition and Transport in Plaransport in Plantsnts
Pressure-Flow of Phloem Pressure-Flow of Phloem TransportTransport
Positive pressure drives sap in sieve Positive pressure drives sap in sieve tubestubes
Sucrose is actively transported into Sucrose is actively transported into sieve tubessieve tubes
Water follows by osmosisWater follows by osmosis
Increase in volume creates flow that Increase in volume creates flow that moves water and sucrose to a sinkmoves water and sucrose to a sink
30Pressure-flow Model of Phloem Transport
31Nutrition and TNutrition and Transport in Plaransport in Plantsnts
ReviewReview
Essential Inorganic NutrientsEssential Inorganic NutrientsSoil FormationSoil Formation
Soil ProfilesSoil Profiles
Soil ErosionSoil Erosion
Water & Mineral UptakeWater & Mineral Uptake
Transport MechanismsTransport MechanismsWaterWater
Organic NutrientsOrganic Nutrients
Nutrition and Transport in Plants
Ending Slide Chapter 26