Plant tissues Chapter 25

Basic structure of a flowering plant Shoot system: Stem: ___________ ________________ Leaves: intercept sunlight for ________________ Reproductive organs: e.g., flowers Root system: absorb _________ and dissolved _________; anchor plant in soil

Basic structure of a flowering plant Ground tissues: make up the bulk of the plant body; tissues specialized for ______________and for __________ Vascular tissues: ____________________________________ __________________________________________________ Dermal tissues: ____________________________________ Monocot: plant embryo has a ____________________ Eudicot: plant embryo has _____________________

Main types of tissue Simple tissues: consist primarily of one type of cell Complex tissues: have two or more cell types parenchyma collenchyma sclerenchyma (fibers) xylem phloem epidermis

Simple tissues Parenchyma: composed of living cells with different functions; main component of ____________________ Collenchyma: composed of living cells with unevenly thickened __________; __________________________ Sclerenchyma: composed of cells that die when mature; lignin-reinforced cell walls remain and _______________ _______________

Complex tissues Epidermis: dermal tissue; ________________ Ground tissue: consists mostly of ______________ Mesophyll: _______________________________ Complex vascular tissues: Xylem: __________________________________________ _______________________________________________ Phloem: _________________________________________ _______________________________________________

Tissue organization in stem Stems form the basic structure of a flowering plant Provide support and keep leaves positioned for ___________________________ Parts of the stem: Node: region where new ________________form Internode: _______________________________ Vascular bundles__________________________________ ________________________________________________ ________________________________________________

Cross section of stems

Variations of stems/Modified stems Stolons: _____________________________ ____________________________________ ____________________________________ Bulbs: _______________________________ ____________________________________ ____________________________________ Corms: ______________________________ ____________________________________

Variations of stems/Modified stems Tubers: _____________________________ ___________________________________ ___________________________________ Rhizomes: __________________________ ___________________________________ ___________________________________ Cladodes: ___________________________ ___________________________________ ___________________________________

Leaf structure Most leaves are thin, with a high _______________ ratio Main organs of ___________________ Function in _______________________ Major site of _________________________________ Monocot leaves: ________________________________ _____________________________________________ Eudicot leaves: ________________________________ _____________________________________________

node blade petiole sheath lateral bud blade node stem Leaf structure

Internal structure

vein mesophyll

Roots Roots take up ______________and __________________, and transport these substances Monocot roots: Fibrous root system: ____________________________________ _______________________________ Eudicot roots: Taproot system: __________________ __________________________________ __________________________________

Root structure Vascular cylinder: __________________ __________________ Root hairs: _________ __________________ __________________ __________________ Endodermis: ________ __________________ __________________ Pericycle___________ __________________ __________________ __________________

Growth in plants All plant tissues arise from the activity of ________________ Meristems: _________________________________________ __________________________________________________ When meristem cells divide, some of their descendants differentiate Give rise to vascular, ground, and epidermal tissues as they enlarge and mature

Primary growth Plant parts lengthen by activity at _____________________ in the tips of shoots and roots This lengthening is called _______________________________ Shoots: primary growth occurs at the ________________(the shoot’s tip), undifferentiated cells divide rapidly. Lateral buds form at _____________ Roots: cells in the _________________of a root tip divide repeatedly, some differentiate, ____________ forms for protection

Secondary growth Many eudicot and gymosperm species undergo _________________________________ Stems and roots thicken and become _____________________ Thickening originates at ___________________________: Cylindrical layers of meristem that run lengthwise through stems and roots Vascular cambium: ___________________________________ __________________________________________________ Wood: accumulated secondary xylem Cork cambium: lateral meristem that gives rise to __________ Cork: waterproofs, insulates, and protects the surfaces of woody stems and roots

pith endodermis primary xylem secondary xylem vascular cambium phloem cork cambium parenchyma collenchyma cork wood bark periderm

Tree rings Rings visible in the heartwood and sapwood are regions of early and late wood. In most temperate zone trees, one ring forms each year. Sap oozes from xylem in this freshly cut pine log. ____________is secondary xylem that is still functional. As a tree ages, the oldest xylem at the center of its trunk may no longer be able to transport fluid because it has clogged. This older xylem is called __________________.

Tree rings Tree rings can be used to: __________________________________________________ __________________________________________________ __________________________________________________ __________________________________________________

Sequestering carbon in forests Stephen Sillett studied a 3,200-year-old giant sequoia tree The tree holds more than 54,000 cubic feet of wood and bark Important for carbon offsets: financial instruments designed to reduce emissions of carbon dioxide Carbon incorporated into sturdy plant tissues such as wood can stay out of the atmosphere for thousands of years