Chapter 3 Nutrient absorbing structures Roots
Chapter 3 Nutrient absorbing structures: Roots
Scope of this lecture Root functions: for plant, soil and ecosystem Root structure and pathways for uptake of nutrients the symplast and apoplast Root architecture(结构) and morphology(形态) Responses of roots and root systems to environmental stress Root hairs and their functions Introduction to combined strategies for efficient nutrient uptake Carbon costs of root processes [if there is timel
Scope of this lecture • Root functions: for plant, soil and ecosystem • Root structure and pathways for uptake of nutrients: the symplast and apoplast • Root architecture(结构)and morphology(形态） • Responses of roots and root systems to environmental stress • Root hairs and their functions • Introduction to combined strategies for efficient nutrient uptake • Carbon costs of root processes [if there is time]
taproot Fibrous root Roots are natural selection's design solution to the problems of obtaining resources from a heterogeneous(异质,多相), porous(多孔的), emi-compressible(半刚性的) medium containing solid, liquid and gaseous phases. (Robinson 1991)
“Roots are natural selection’s design solution to the problems of obtaining resources from a heterogeneous（异质，多相）, porous（多孔的）, semi-compressible（半刚性的） medium containing solid, liquid and gaseous phases.” (Robinson 1991) Fibrous root taproot
Roots and root systems Functions(for plants): 1.Uptake of soil nutrients 2.Uptake of water 3. Storage(e.g. carrots, radish, sugar beet 4 Phytohormone(植物激素) production 5. Habitat for micro-organisms symbiotic N2 fixing bacteria固氮细菌( (internal) mycorrhizal fungi菌根真菌( (internal& externa) rhizosphere根际 bacteria& fungi( external)
Roots and root systems Functions (for plants): 1.Uptake of soil nutrients 2.Uptake of water 3.Storage (e.g. carrots, radish, sugar beet) 4.Phytohormone（植物激素） production 5.Habitat for micro-organisms: - symbiotic N2 -fixing bacteria固氮细菌 (internal) - mycorrhizal fungi菌根真菌 (internal & external) - rhizosphere根际 bacteria & fungi (external)
Roots: a dynamic system 6 days 10 days 17 days Courtesy Mac Kirby CSIRO Land and Water
6 days 10 days 17 days Courtesy Mac Kirby CSIRO Land and Water Roots: a dynamic system