Topic 9

• Fertilization


  After pollination, from each pollen grain on the stigma a tube grows down the style to the ovary. The pollen tube carries male gametes to fertilize the ovary. The ovary is located inside a small rounded structure called an ovule. The fertilized ovule develops into a seed and the ovary develops into a fruit.
• Seed Dispersal


  Scattering of seeds; can be done by animals, insects, air, or water.
• Stigma


  Sticky and captures pollen from visiting pollinator.
• Petals


  Large and help pollinators find the plant.
• Sepals


  Protect the flower bud during development and at night when the buds close
• Anthers


  Produce pollen, containing the male gametes
• Filaments


  Hold the anthers in a position where they are likely to brush pollen onto visiting pollinators
• Carpel


  Female part of the flower. Consists of stigma, style, and ovary.
• Style


  Holds up stigma.
• Ovary


  Located inside a small rounded structure called an ovule.
• transpiration


  the inevitable consequence of gas exchange in the leaf; absorption of carbon dioxide can also lead to evaporation of water though leaves and stems
• Leaf


  primary organ for photosynthesis
• stomata


  pores in waxy cuticle that allow gas exchange
• guard cells


  around stomata that adjust opening and closing of stomata to aid in water conservation
• replacing losses from transpiration

  plants transport water from roots to leaves to replace losses from transpiration
• xylem


  tissue in vascular plants that helps provide support and conducts water and nutrients upward from the roots; replaces water lost through transpiration; path of water from soil to leaves (soil to roots through osmosis and active transport of minerals-adhesion and cohesion as well as pull from transpiration drive water up cell walls (apoplast) and through the cytoplasm (symplast) )
• xylem structure helps withstand low pressure


  cohesive property of water and structure of xylem vessels allow transport under tension; xylem can withstand very low pressure without collapsing due to strengthening characteristics of walls (pressure in xylem is less than atmospheric pressure)
• tension in leaf cell walls maintains the transpiration stream

  adhesive property of water and evaporation generate tension forces in lead cell walls
• adhesion in the xylem


  water is attracted to hydrophilic properties of cell walls of xylem; triggers by transpiration even if pressure in plant is low; low pressure leads to transpiration-pull within plant which allows water to travel to tops of plants and against gravity; this process is passive driven by thermal energy; depends on cohesion of water molecules to transmit the pulling forces
• active transport of mineral in roots


  active uptake of mineral ions in roots causes absorption of water by osmosis; water travels into roots through osmosis ([solute] is higher in roots than soil, [solutes] is due to active transport-mineral ions can be carried to specific protein pumps through osmosis, to speed up mineral ion movement plants for a symbiotic relationship with fungi=mutualistic: both benefit)
• integral proteins

  transport minerals form soil into roots through active transport; once minerals have crossed over into plants they attract water through a concentration gradient
• drawing xylem vessels

  
• translocation occurs from source to sink


  plants transport organic compounds from sources to sinks
• phloem


  vascular tissue responsible for the transport of sugars from source tissues to sink tissues (found in stems, roots, leaves; composed of sieve tubes)
• translocation


  transport of organic compounds through plant
• sinks and sources may switch

  phloem transport nutrients in either direction through pressure gradients (active process)
• pressure and water potential differences play a role in translocation

  incompressibility of water allows transport by hydrostatic pressure gradients; an increase in sucrose and other carb concentration draws water into companion cell through osmosis (build up of pressure; water will move from high pressure to low pressure)
• at the sink

  sucrose is used as energy or converted to starch which leads to a decrease in [solute] and water is transferred to xylem to aid in transpiration stream
• xylem and phloem

  
• phloem loading

  active transport is used to load organic compounds into phloem sieve tubes at sourcebringing sucrose into the phloem (sucrose is transported through phloem because it is not readily available to metabolize for energy)
• apoplast pathway


  transport between nonliving part of the plant (cell walls, intercellular space; little resistance against movement of water; uses active transport power by H+ gradient to carry sucrose into the companion cell-sieve tube complex)
• symplast pathway


  transport between living parts of the plant (protoplasts (cell) connected by plasmodesmata (connections between cells); sucrose is converted to an oligosaccharide at the companion cell)
• petal

  attracts pollinators
• anther


  contains pollen (stamen)
• filament


  supports anther (stamen)
• sepals


  cover/protect developing flower
• stigma


  pollen landing site
• style


  pollen tube grows down style from stigma to ovary
• ovary


  contains ovules (ovules contain egg nuclei and develop into seeds when fertilized)
• reproduction in angiosperms

  pollination: pollen carried from anther of one flower to stigma of anotherfertilization: pollen tube grows down from stigma to ovary through the style; pollen is delivered to ovum and fertilization occursseed dispersal: once seed has developed in ovule it is ready for wind, animal, or water dispersal