Meristems and Primary Growth

Zygote

fertilized cell from fusion of egg and sperm, begining of sporophytes lifecycle in plants

Microgametophyte

pollen in plants, male gametophyte

Megagametophyte

female gametophyte, egg cell in plants, sporophyte (maternal cell)

Embryogenesis

mitotic cell division lay down basic tissue and body plan for developing plant

Suspensor

temporary structure, connects developing embryo to surrounding tissue and helps position embryo during development

Hypophysis

uppermost cell of suspensor, contributes to formation of root apical meristem and root cap

Protoderm

embryonic tissue that develops into plants dermal tissue system

Ground tissue meristem

embryonic tissue that develops into the ground tissue system, including tissues such as cortex and pith

Procambium

embryonic tissue that develops into the primary vascular tissues: xylem and phloem

Meristems

ready to initiate growth upon germination

Differentiate

when undifferentiated celles recieve molecular signals from neighbors to differentiate and dictate spacial position and what to become

Cotyledon

embryonic leaf that forms during seed development and often stored or absorbed nutrients that support young seedling

Primary growth

growth in length caused by dividing and differentiating cells at apical meristems

SAM

region of actively dividing cells as tip of shoot that produces new cells for the growth and development of stems, leaves, and flowers, must maintain proper balance of cell differentiation to meristem cell renewal

RAM

region of actively dividing cells near tip of root that produce new cells for root growth and development

Fasciation

due to loss of signal controling balance in SAM, over-proliferation of meristem cells

Phytomers

repeating units laid down by meristem on shoot made up of: axillary bud, internode, node, and leaf

Xylem

vascular tissue that transports water and dissolved minerals from roots to rest of plant

Phloem

vascular tissue that transports sugars and other organic compounds between different parts of plant

Pith

ground tissue in center of stem, inside vascular tissues, made of mostly parenchyma cells and mostly just for storage

Cortex

ground tissue located between dermal tissue and vascular tissue, functions in: storage, photosynthesis, and support

Anastomosis

joining of leaf and stem veins, occurs at nodes

Root cap

group of cells that covers and protects root apical meristems as root grows

Root hairs

long, thin extensions of individual root epidermal cells that increase roots surface area

Endodermis

single layer of cells forming the innermost boundary of the root cortex, regulates movement of water and dissolved substances into vascular cylinder or stele

Pericycle

layer of cells just inside the endodermis, surround the roots vascular tissues, retains ability to divide and is tissue that lateral roots originate from