Module 2

• does it always matter if your system is better


  Not always about which system is better, but what is more beneficial for the environment the plant lives in.
• where are angiosperms found


  Excluding Antartica, flowering plants can be found on all the continents. Overall, represent 90% of all living plant species.
• where are mosses found and trait

  Their lack of roots allow mosses to grow on rocks and trees of taiga, deciduous and rain forests; also makes excellent ground cover.

  Desiccation allows mosses to survive long, frozen winters in tundra and taiga.
• where are ferns found and what trait

  Large pinnate frond leaves allow ferns to capture low levels of light at the bottom of forest floor in the temperate forests of Europe and wet, humid rain forests.
• what did conifers adapt to

  Conifers adapted to the arid (low water) conditions of the Jurassic andTriassic by forming needle leaves (reduce water loss via gas exchange) and developed vasculature that prevents air blockages. These adaptations, along with their ability to keep their leaves in the winter (“evergreens”), allow them to thrive in the short, dry growing seasons of taiga forests in the Northern Hemisphere (Canada’s Boreal Forest).
• what are dicot angiosperms trait

  Broad leaves with branched, reticulate veins, usually attachedto stem via petiole.
• what type of plants are dicot angiosperms

  Deciduous trees and shrubsoak, maple, sycamore, poplar
• angiosperm dicot agriculture


  pumpkin, nightshades, legumes
• what type of flowers do dicot angiosperms produce

  roses, poppies, buttercups, sunflowers, magnolias
• monocot angiosperm traits


  Narrow leaves withparallel primaryveins, and sessile(direct) attachmentto stem. Leafsheath is wrappedaround stem.
• monocot angiosperm plants


  Warm climate, treespalms, Dracaena sp
• monocot angiosperm agriculture


  grasses, sedges (wheat, oats, rice,maize), sugar cane, bamboo
• monocot angiosperm flowers


  lily (daffodils, onion, garlic), orchids
• dicot vs monocot angiosperm advancement levels

  • Dicot: Most have primitive flowers, with flower parts in multiples of 4 or 5.
  • Monocot: Most have advanced flowers with flower parts in multiples of 3.
• primary growth


  Most primary growth occurs at the apices (or tips) of shoots and roots.Increase in shoot and root length by cellular division (mitosis) in apical meristems
• what are meritstems


  Meristems are present in all plants(mosses to vascular seed plants)

  Meristems are small populations of rapidly proliferating

  (dividing) cells that produce all cells and tissues
• what are shoot made up of

  Shoots = aerial organs = stem + leaves + buds + flowers
• what are cells of meristems called

  • Cells of the meristem are called initials and are totipotent: capable of giving rise to any cell type
  • diffrentiation is maturation of acell to a specific function.
• Shoot Apical Meristem (SAM)

  -Roots and stems grow in length, by cells dividing below growingpoint in the shoot apical meristem (SAM) and above the root apical meristem (RAM)

  -SAM gives rise to stem, leaves and flowers.-Dividing cells are small, dense with cytoplasm. Mature, differentiated cells are larger and highly vacuolated.
• Root Apical Meristem (RAM)

  -RAM resides in quiescent center of root tip, above root cap.

  -Dividing cells are small, dense with cytoplasm.

  -Mature, differentiated cells are larger and highly vacuolated
• Lateral Meristems


  • Shoots can grow outwards, forming leaves, flowers and branches from axillary (lateral) meristems; each lateral shoot will have own SAM at apex.

  • Roots can also branch from primary root with lateral meristems; each lateral root will have own RAM at root tip.

  • Lateral branching can also be referred to as secondary branching, but this is still primary growth
• 3 main plant tissue types

  dermal, ground and vascular.
• what are plant tissues made of

  Plant tissues are complex, made up of more than one cell type.

  Plant tissues made up of living and dead cells at maturity.
• what does secondary cell wall contain

  The primary cell wall contacts the plasma membrane

  • The middle lamella is a pectin rich layer that “cements” or binds neighbouring primary cell walls to each other

  • The secondary cell wall, is between the plasma membrane and primary cell wall and is reinforced with lignin (lignification)
• are cells with secondary cell walls alive at maturity


  Cells with secondary cell walls are not alive at maturity: lignification blocks intercellular transport via desmotubules, protoplast dies
• what is the lumen

  Former protoplasmic space referred to as lumen
• does secondary wall mean lignification


  Secondary walls = lignification (seedless vascular plants and vascular plants
• does secondary cell wall mean secondary growth

  Secondary walls ≠ secondary growth (gymnosperms and some dicot angiosperms
• what is the epidermis

  • Provides protection and facilitates gas exchange.
  • In plants with primary growth, dermal tissue is the epidermis: usually one cell layer thick.
  • Shoot epidermis excretes waxy cuticle to protect tissue and prevent water loss.
  • Stomatal pores control gas exchange.
• what are trichomes


  Trichomes are outgrowths of the shoot epidermis. Aide in plant defence. They can be simple hairs or glandular (pictured below), releasing essential oils.
• root hairs


  In root tips, root hairs are outgrowths of the epidermis that absorb water.
• what is ground tissue made of

  parenchyma, collenchyma, sclerenchyma
• parenchyma


  general purpose cells of the plant, provide structure and perform photosynthesis (contain chloroplasts). Alive at maturity.
• collenchyma


  provides flexible support and alive at maturity.
• Sclerenchyma


  provides mechanical support with lignin reinforced secondary walls, dead at maturity.
• most common and least specialized type of plant cells

  parenchyma
• where are parenchyma found

  Makes up majority of groundtissue in leaves, stems,roots, flowers and fruits
• parenchyma appearance


  Polyhedral, large, thin-walledand highly vacuolated (cellspace filled with vacuole)
• parenchyma function


  Photosynthesis, storage, structure (large vacuole) and cell-to-cell transportation
• plant response to mechanical stressors such as wind

  Plants produce more collenchyma cells in responseto mechanical stressors such as wind