Biology: Plant Tissues

Determinate Growth

Plants that stop growing after they reach their mature size

Indeterminate Growth

Plants that continue to grow as long as environmental conditions allow it

Meristems

Regions that undergo active mitotic cell division; allow a plant to grow and replace damaged parts

Apical Meristems

Primary Growth that lengthens: small patches of actively dividing cells near the tip of roots and shoots

Lateral Meristems

Secondary growth that increases girth: produce cells that thicken a stem or root in woody plants

Shoot Apical Meristem

Lengthens the shoot by adding cells

Root Apical Meristem

Lengthens the root by adding cells

Vascular Cambium

Internal cylinder of meristem tissue; produces thin layer between primary xylem and phloem

Cork Cambium

Gives rise to parenchyma to the inside and cork to the outside

Cork

Densely packed, waxy cells on the surfaces of mature stems and roots

Heartwood

Innermost darker wood that gradually becomes unable to conduct water through time

Sapwood

Outer lighter portion that transports water and dissolved minerals

Ground Tissue

Fills the spaces between more specialized cell types inside roots, stems, leaves, fruits, and seeds

Dermal Tissue

Covers the plant; herbaceous plants have epidermis, woody have tough bark

Epidermis

Single layer of packed, flat, transparent, parenchyma cells

Cuticle

Waxy layer that coats the epidermis and is impermeable to water, CO2, and O2

Stomata

Pores through which leaves and stems exchange gases with the atmosphere

Guard Cells

Surrounds stomata and controls its opening and closing

Xylem

Transport water and dissolved minerals from the roots to all the parts of the plant

Phloem

Transports dissolved organic compounds, primarily sugars

Vascular Bundle

Strand of tissue containing xylem and phloem, often with collenchyma or sclerenchyma fibers