plant nutrition, structure, and transport

• plants get their nutrients from above and below ground: light, CO2, H2O, O2, minerals from soil
• vascular system allows for transport of nutrients, from sources to sinks
• light & CO2 harvested by leaves, the leaves' ability to absorb depends on phyllotaxy, leaf area index, leaf size and orientation, shoot height and branching pattern
• leaf area index is the ratio of upper leaf surface divided by surface of land it grows on
• phyllotaxy is the arrangement of leaves on stem, handles leaf area index
• water & minerals are harvested in plants with roots
• roots' ability to absorb depends on surface area & concentration of resources in soil
• roots can respond to the local environment, increasing branching to nutrient rich areas
• what other factors contribute to successful absorption via surface area in plants?

  root hairs and mycorrhizae
• decrease roots branching happens due to competition w roots from same species
• water is pulled upward from roots in xylem sap
• the xylem sap transports fluid made of water and dissolved minerals
• transpiration is the evaporation of water from a plant’s surface, drives xylem sap flow
• negative water pressure in leaves draws water up by xylem
• capillary action for transpiration happens with hydrogen bonding
• transpiration is regulated by stomata, low concentration of water in leaves creates a concentration gradient
• sugars are transported from sources to sinks with the phloem sap
• what is the role of fungi in plant nutrition?

  mycorrhizae, fungal symbiosis to help plants get nutrients from the soil and water, plants give fungi sugars from photosynthesis
• what are the three major plant organs?

  roots, leaves, stems
• roots absorb water and minerals from the ground below
• the two main root systems are the taproot system (gymnosperms and eudicots) and the fibrous root system (monocots)
• what other functions of roots can be selected?

  • stabilize in soil (prop roots),
  • wide roots (buttress roots),
  • storage roots (beets, store excess sugar and energy),
  • pneumatophores (provide oxygen for underwater roots)
• leaves take up CO2 and light from above ground, primary purpose is photosynthesis
• a petiole attaches blade of leaf to a stem
• the three types of leaves are compound leaves, simple leaves, and doubly compound leaves
• a compound leaf includes a petiole, axilary bud, and 6-7 leaflets
• a doubly compound leaf includes, a leaf with multiple leaflets, and a leaflet with more leaflets
• extra features of leaves include spines, tendrils, storage leaves and reproductive leaves
• stems connect roots and leaves
• rhizomes are the part of the stem that is underground
• stolons are the part of the stem that is above ground
• roots, stems and leaves share continuous tissue types such as ground tissue cells or dermal (protective) cells
• parenchyma have basic metabolic functions, food storage, photosynthesis, differentiable
• collenchyma are grouped in strands, flexible support, maintains shape
• sclerenchyma are dead at maturity, cell walls w lignin, inflexible support, oak branch
• the three types of ground tissue cells are parenchyma, sclerenchyma, and collenchyma
• xylem conduct water and are made of dead cells, form tubes/long straws, tracheids, and vessels
• phloem are sugar water solution conducting , made of living cells, have a sieve tube
• how are monocots arranged?

  parallel veins, have epidermis, bundles of vascular tissue (xylem & phloem) randomly dispersed
• how are eudicots arranged?

  vascular bundles arranged in a single ring with xylem on the inner edge and phloem on the outer edge