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Plant-Environment Relationship

Plant-Environment Relationship. HO Pui-sing. Contents. Development of Plants Equatorial / Tropical Rain Forest Tropical Desert Vegetation Local Plant-Environment Relationship The Relationship of Biomes to Ecolines. Development of Plants. Classification of Plants

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Plant-Environment Relationship

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  1. Plant-Environment Relationship HO Pui-sing

  2. Contents • Development of Plants • Equatorial / Tropical Rain Forest • Tropical Desert Vegetation • Local Plant-Environment Relationship • The Relationship of Biomes to Ecolines

  3. Development of Plants • Classification of Plants • Factors affecting plants development

  4. Classification of Plants • Life form of plants • Trees • Shrubs • Lianas • Herbs • Vegetation structure • Forest • Woodland • Lichens

  5. Factors affecting development • Plant habitats • Water availability • Temperature • Time • Human

  6. Plant habitats • Plants affect landform and soil (Env.) • Different conditions of slopes, drainage and soil type will create different plant environment = plant habitats

  7. Water availability • Types of plants • Xerophytes • Hygrophytes • Mesophytes • Tropophytes • Deciduous plants • Evergreen plants

  8. Temperature • Plant growth: photosynthesis, flowering, fruiting and seed germination • Water availability: rate of transpiration and evaporation • Damage: damage the cell tissues for too cold • Frontier: a boundary which a plant species cannot survive.

  9. Time • Plant and animal communities succeed one another on the way to a stableendpoint, making up an ecological succession • Climax vegetation (climatic control) • Subclimax vegetation (non-climatic control)

  10. Reason for succession • Results of species competition in a given environment. • Populations of well-adapted species replace earlier ones now less well equipped to compete in the altered conditions. • There is a gradual change in the community.

  11. Process of succession • Pioneers (annual herbs, weeds) • Grasses and shrubs • Pine seedlings • Pine forest • Broad-leaved deciduous trees (oak forest) Climax forest • Climax community = balance between Vegetation and physical environment.

  12. Process of succession Pioneers Grasses & Shrub Pine seedings Deciduous forest (Climax)

  13. Process of succession

  14. Patterns in successional processes • Development of soil mature • Height of plants increases and strata clear developed • Biomass (productivity) increase • Species increases • Create new micro-climates • Species replace one another (succession) • Climax community forms (stable, balance)

  15. Human impact on vegetation • Clearing forest disturbs the climax vegetation • Introduce new plant disease • Extinction of a original plant species • Changing soil structure and properties • Reasons: farming, mining, urbanization and industrialization…….

  16. Tropical Rain Forest Congo Basin Amazon Basin South-east Asia http://www.radford.edu/~swoodwar/CLASSES/GEOG235/biomes/rainforest/rainfrst.html

  17. Natural Environment • High insolation • Monthly temperature between 26oC and 27oC • Annual rainfall usually more than 2000mm • Convection Rain is common • Hot and wet throughout the year

  18. Characteristics of TRF Vegetation • Evergreen forest • Vegetation Layers • Leaves • Drip-tips • Roots • Cauliflory

  19. Evergreen • No Seasonal variation • Leaf-growth, flowering, fruiting, leaf-fall…….go on continuously • Trees can live to a great age

  20. Emergents Layer Canopy Layer Middle Layer Shrub Layer and Understorey Vegetation layers

  21. Vegetation Layers • Emergent layer • very tall tree with broad crown (30-40m) • few in number • Canopy layer • a continuous cover (20m) • Middle layer • younger trees (5-15m) • Shrub layer and undergrowth • little growth because of shade

  22. Leaves • Uniform, dark green, glossy, leathery, oval and broad-leaved • Strong insolation and transpiration a heavy cuticle leathery.

  23. Waxy Leaves and Drip-tips

  24. Buttress Roots

  25. Caulifory

  26. Types of vegetation • Tree species • Epiphytes • Parasites • Tree Ferns • Undergrowth • Saprophytes • Mangrove swamps (riverine)

  27. Trees and Climbers

  28. Epiphytes and Parasites

  29. Undergrowth

  30. Mangrove Mangrove swamps Prop-roots Radicle

  31. Tropical Desert Vegetation

  32. Natural Environment • Among the driest places on earth (<250mm) • Mean annual temperature above 18oC • Low relative humidity • Irregular and unreliable rainfall • Highest percentage of sunshine of any climate • Large diurnal temperature range • Highest daytime temperature of any climate • Annual precipitation < half the annual potential evapotranspiration

  33. Tropical Desert Vegetation • Characteristics of the vegetation • Types of vegetation

  34. Characteristics - Morphological • Extensive root systems (vertical or horizontal) • Deeply penetrating roots reach permanently wet soil or ground water store • Horizontal roots may extend for 5-20m • Low shoot-to-root ratio (1:3.5 to 1:6) • Special leaves (small, roll, spiny and shed foliage) for reduce transpiration and preserve water.

  35. Characteristics - Anatomical • Cuticularisation produces a watertight and waxy-like surface • Lignification provides mechanical support • Low, rounded shapes can reduce damage by strong wind • Many hairs

  36. Characteristics - others • Sparsely distribution for not enough water supply • Low biomass, few species, lack of competition

  37. Types of vegetation • Ephemeral annuals • Succulent perennials • Non-succulent perennials

  38. Ephemeral annual • 50-60% of desert plants • Complete its full life cycle within 6-8 weeks (short life cycle) • Small size, shallow roots • Fastgerminating, growing, flowering and seeding • Extensive germination immediately after precipitation • Eg. Desert plantains, desert fescue

  39. Ephemeral annual

  40. Succulent perennials • Enlarge the parenchyma tissues with the addition of water • Stems and leaves allow store water during rainy season • Stomata are closed during day and open at night • Eg. Catus

  41. Succulent perennials

  42. Non-succulent perennials • Can be divided into three types • Evergreens • Drought-deciduous • Cold-deciduous • Commonly found where a little water is available. (wadis, oases, perennial rivers) • Eg. Tamarisks, acacias, grasses, palms

  43. Non-succulent perennials

  44. Local Plant-Environment Relationship • Altitude zones of vegetation • The local variation of vegetation in TRF • The local variation of vegetation in desert

  45. Altitude zones of vegetation • Vegetation changes with an increase in elevation because the following reasons • Temperature drops • Relative Humidity increase • Precipitation increase • Orographic rain in windward slope • Rain shadow in leeward slope

  46. continues • Light intensive and day time increase • Outgoing radiation at night increase • Large diurnal range of temperature • Permanent snowcaps exist on very high Mts. • Faster wind speed • Aspects – South facing slope vs. North facing slope

  47. Altitude zones of vegetation

  48. Altitude zones of vegetation

  49. Tropical Mountains

  50. Tropical Mountains • Hot country <1000m • Temperate country 1000-1800m • Cold country 1800-3500m • Snow country or frost country >3300m

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