plants characteristics

• Diversity


  -Variability among living organisms

  -normally associated with morphological traits

  -response to one of the three main functions

  - Forms follow function
• Plants


  -Eukaryotes

  -Multicellular

  -Autotrophs

  -Have a cell wall
• Plant systems


  -Shoot system: gets light and direct contact with air

  -Root system: no light or contact with air
• Meristematic tissue


  -Ability to reproduce asexually

  -small, cuboidal densely packed cells

  -thin cell walls, large nuclei, and small vacuoles almost no intercellular space

  -capable of stretching, enlarging, and differentiating into another type of tissue

  -found in tips of roots, stems, nodes of the stem, between xylem and phloem, under the epidermis, and producing branch roots
• Apical tissue (subdivision of meristematic tissue)

  -Found in roots

  - During division, it helps in cell enlargement

  -Influences the shape of mature plants
• Lateral tissue (subdivision of meristematic tissue)


  - Found along stem and roots

  -Has a vital role in increasing the width of the plant
• Intercalary (subdivision of meristematic tissue)

  -Forms the internodes, mainly found at the bases of young leaves or branches

  -Responsible for lengthening and forming branches from twigs
• Parenchyma


  -Largest portion of plant cell

  -Circular shape, very thin walls, very large vacuoles

  -Synthesise and store food products, control plant's metabolic reactions and regeneration
• Palisade Parenchyma


  -Photosynthetic parenchyma

  -tightly jointed cylinder-like cells, with little intercellular

  space

  -Usually on the face of the leaf facing the sun, below the upper epidermis

  sun-intensive leaves are smaller and thicker (more layers of palisade parenchyma); shadow leaves have greater surface but thinner(less palisade layers)
• Spongy Parenchyma


  -Cells also contain chlorophyll, but cell density is much smaller

  -Circular cell, with bigger intercellular spaces so that air from outside can travel

  -Close to lower epidermis
• Collenchyma


  -Specialized type of parenchyma

  -Found in the green parts of plants

  -Elongated cells with unevenly thickened walls

  -Provides certain rigidity while allowing growth of the organisms
• Sclerenchyma


  -Rigid, non-living cells that provide strength

  -Thick lignified secondary walls contain lignin

  two types: sclereids and fibres
• Sclereids


  Short, irregular with thick lignified walls
• Fibres


  Long and slender, arranged in threads
• Plant stem


  • Important difference among plant groups is vascular tissue
• Vascular tissue


  Allows to transport nutrients
• Xylem


  • Transports from roots to leaves, unidirectional, inner part
• Phloem


  • Bidirectional, outer part
• Heartwood


  Completely dead, structural function
• Xylem


  Has been lignified
• Seed


  • Provides protection against temporary drought or cold: dormancy
  • Allows survival during long cold or dry periods: perennation
  • Provides nutrients for the take off
• Seed appears in gymnosperms
• Seed


  • Adaptation for dispersal: by wind, animals
• Cotyledon


  First leaves of a plant
• Flowers


  • Reproductive structures, only in evolved plants, increase chances of pollination by enabling a new type: zoophilous
• Flowers appear in angiosperms
• Main classification of plants


  • Gymnosperms
  • Angiosperms
• Gymnosperms and angiosperms have seeds but angiosperms have flowers