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Evolution, one is short one is long, pleisomorphy, synapomorphy, tracheid…

- - - - mosses and hornwort SPOROPHYTES
    - - moss and hornwort LIVERWORTS
      - (basal lineages)
  - - - hormone-based stress receptors!
    - - cavitation is air bubble formation that affects water transportation
    - - Water Use Efficiency (WUE)
      - how effectively a plant coverts water into carbon via photosynthesis
  - - - irregularly spaced with epidermis
      - kidney bean shaped guard cells
      - undergo multiple division rounds before forming guard cells
    - - narrowly shaped with linear arrays of epidermis
      - dumbbell shaped guard cells
      - guard cells form alongside subsidiary cells without repeated assymetric divisions like eudicots do
      - their subsidiary cells influence the speed/sensitivity of light, CO2, and humidity
- - - - tracheid xylem are dead at full maturity :!!:
    - - resembled early bryophytes
      - mosses (an early land plant) now have stomata on their sporophytes
  - - - flowers
      - the last great plant innovations
      - highly modified shoots
      - co-evolutionary relationships
      - fruits and vegetables
    - - conifers, cycads, and ginkgo
      - rely soly on tracheids for water transport
      - have an additional remedy for cavitation: torus-margo pit membrane
        
        this membrane closes a pore that is close to a neighboring cell that has experienced embolism/air bubble
        
        thus, gymnosperms can handle extreme conditions (drought or cold)
      - have mainly sieve cells
- - - - 1) protoderm
        
        outermost layer
        
        becomes dermal tissue
        
        root epidermal cells that control nutrient and water uptake
      - 2) procambium
        
        under the protoderm
        
        becomes xylem & phloem (vascular tissue)
        
        transports nutrients/water and supports height and width
      - 3) ground meristem
        
        space between protoderm and procambium
        
        makes the ground tissue system:
        the parenchyma, collenchyma, and sclerenchyma
  - - - apical meristem dominance
      - 3D growth (instead of 2D)
        
        mosses still show 2D growth -->
        
        young moss gametophyte development
        
        1) spores divide mitotically and form filaments
        
        2) the cells at the filament tips elongate and make linear arrays
        
        3) some cells in the linear arrays experience 3D growth
        
        4) these cells bulge into a round shape and make leafy shoots
      - bifurcating sporophyte
        
        also known as polysporangiophytes, produce multiple sporangia
        
        eventually gave way to anisotomous branching, where one daughter branch outgrew the other
      - lateral movement of terminal sporophytes
- - - - primitive water conducting cells that lack plasmodesmata
        
        lack of it allows them to refill with water after cavitation.
        
        however it is only effefficient in small plants
      - lack lignin, so they look structurally different
    - - predominantly found in angiosperms
      - form vessels that transport water faster than tracheids
      - their ends have perforation plates
        
        large open spaces without cell walls or membranes
      - more suscpetible to cavitation :fire:
      - https://youtu.be/JSqEEWkw1VU
    - - are dependent on xylem for water
      - early land plants, like bryohphytes, did not have phloem or other vascular tissue
        
        they had food conducting cells instead that derived from parenchyma cells :red_flag:
        
        food conducting cells increased plasmodesmata, mitochondria, and plastids
        
        note: plasmodesmata are small channels between sieve cells and ccs that allow for intercellular communication
        
        tonoplast breakdown (membrane that surrounds the large central vacuole) later occurs
        
        these adaptations paved the way for sieve tube elements
        
        the early parenchyma cells that these cells came from are similar to leptoids in modern mosses
      - has factors to help protect against damage/pathogens
        
        callose
        
        polysaccharides that surround sieve pores when injured
        
        blocks pores to prevent pathogens and loss of nutrients
        
        p proteins
        
        only in angiosperms
        
        aggregate and also seal off sieve pores
      - https://youtu.be/Ix1JgAn3_H0
    - - the first true water conducting cells
      - lignified #
        
        before lignin there was only hydrostatic pressure
        
        early tracheophytes were only partially lignified
        
        modern tracheophytes are now fully lignified with helical and annular thickenings
      - primary conductive cells in gymnosperms (used to be for early vascular plants also)
      - connected by pit pairs for limited water movement
      - more preventative of cavitation #
    - - wood = secondary xylem
      - secondary growth
        
        prominent in spermatophytes
        
        growth/mitosis of vascular cambium forms the xylem and phloem
        
        monocots LACK IT
        
        occurs in gymnosperms and angiosperms
        
        in gymnosperms the vascular vambium is made of:
        
        fusiform initials
        
        has cells that make xylem and phloem
        
        ray initials
        
        has cells that make parenchyma cells
        
        has 2 growth orientations:
        
        anticlinal division
        
        expands diameter through vascular cambium growth (left to right)
        
        periclinal division
        
        expands cambium ring outward through xylem cell growth on inner cambium (up and down)
      - anatonmy determines wood maturation
        
        heartwood
        
        nonliving, central core
        
        darker in color
        
        because of resins and tannins
        
        NO LONGER TRANSPORTS WATER, soly structural support
        
        angiosperm wood is referred as hardwood because they lack vessels
        
        sapwood
        
        lighter in color
        
        vital for water transportation and plant health
      - KNOW HOW TO DRAW CROSS SECTION
- - - - covered in cuticle to prevent water loss
    - - can provide protection from predators or reflect excess light
  - - - most versatile , adaptable, and common cells
      - store nutrients and water
      - wound repair
      - have thin cell walls and large vaucoles
    - - elongated and unevenly thick
      - provide flexible support
      - found in actively growing regions
    - - provide rigid support
      - have thick lignified cell walls
      - have 2 types:
        
        fibers (long and slender)
        
        sclerids (short and variable in shape)
  - - - includes:
        
        tracheids and vessel elements #
        
        fibers
        
        structural support for xylem
        
        (water conducting cells)
        
        tracheids are elongated and tapered (boba straw)
        
        vessel elements are short and continuous tubues
    - - sieve tube cells
        
        specialized for sugar transport
        
        NO nucleus
        
        rely on CCs for metabolic support
        
        in gymnosperms, the phloem consists primarily of seive cells
        
        in angiosperms, the phloem consists of sieve tube elements
        
        sieve tube elements do remain alive (unlike xylem)
      - companion cells
        
        "albuminous cells"
        
        help load and unload sugars
        
        specialized parenchyma cells
      - sclerenchyma and fibers
        
        both structural support for phloem
    - - protostele
        
        most ancient
        
        lycophytes are an example
        
        xylem is surrounded by phloem
      - siphonostele
        
        derived from protostele
        
        "hollow" because it has a center pith surrounded by xylem, then phloem
        
        some are amphiphloic (phloem,xylem,phloem)
        
        some are ectophloic (xylem, phloem surrounding)
        
        leptosporangiate are an example
      - eustele
        
        spermatophytes/angiosperms are an example
        
        present in 2 angiosperm clades: monocots and eudiicots
        
        in eudicots: multiple vascular bundles surround the pith
        
        in monocots: no pith, just protoxylem in center. metaxylem and phloem surrounding it
        
        in each bundle, they show endarch xylem maturation: #
        
        protoxylem, metaxylem, phloem
  - - - stems, branches, leaves, flowers, has apical meristems
      - its apical meristems are responsible for differentiation of new shoot tissues
    - - root hairs, epidermal cell extensions (increase surface area for absorption)
      - its apical meristems are responsible for elongation and development of lateral roots
      - ROOTS
        
        rhizoids were the precursors of roots for anchorage & absorption via osmosis
        
        water transport (from root to steele)
        
        apoplastic transport
        
        passive transport through membranes
        
        symplastic transport
        
        slower transport through plasmodesmata and cytoplasm
        
        lycophytes were then the first groups to develop roots
        
        lycophytes developed further, then euphyllophytes (gymno and angiosperms)
        
        euphyllophytes display EXARCH arrangement of the protoxylem outside of the metaxylem
        
        early roots lacked a root cap and a quiescent center
        
        quiesccent center is a cluster of cells within the apical meristem that are not dividing
        
        surrounding the root apical meristem is the pericycle
        
        the pericycle is a pluripotent layer of cells within the endodermis
        
        3 zones of root cell development:
        
        1) Zone of Division
        
        around the apical meristem
        
        2) Zone of Elongation
        
        contains transition tissues: proambium, protoderm, ground meristem :!!:
        
        3) Zone of Differentation
        
        fully mature/specialized, form root hairs
        
        also have an extra barrier caled the hypodermis beneath the epidermis
        
        Eudicot roots
        
        have resin canals (understudied thick injury fluid)
        
        have laticifers (tube networks that store latex) more common in eudicots
        
        Monocot roots
    - - primary site of photosynthesis
      - flat structure maximizes surface area for light
      - contain stomata
      - LEAVES
        
        "phyllads"
        
        2 distinct forms:
        
        microphylls/lycophylls
        
        small & narrow
        
        single, partial vascular trace
        
        megaphylls/euphylls
        
        in monilophytes (ferns), gymno, and angiosperms
        
        highly vascularized
        
        branched venation and leaf gaps
        
        2 origin theories:
        
        enation theory
        
        microphylls specifically came from enations (scaly leaflike structures)
        
        then microphylls became macrophylls
        
        zimmerman's telome theory
        
        megaphylls came from dichotomously branched stems via 3 prcocesses:
        
        overtopping
        
        planation
        
        webbing
        
        5 phyllad tissue types:
        
        chlorenchyma
        
        made of both parenchyma cells and chlorplasts
        
        collenchyma
        
        makes up the bundle sheath
        
        for flexible support
        
        aerenchyma
        
        made of specialized parenchyma cells (mesophyll)
        
        has air spaces between cells
        
        for buoyancy
        
        vascular tissue
        
        xylem = adaxial :!!:
        
        phloem = abaxial
        
        epidermis
        
        protective dermal tissue
        
        specialized epiermal cells are guard cells