Plant Biology Lecture Review

Flashcards covering key vocabulary terms related to plant cell structure, tissues, organs (roots, stems, leaves, flowers, fruits), and basic plant processes like fall color, juvenility, and seed development.

The Cell

Basic unit of all living things, including plants.

Cell wall

Structural component in plant cells that enables plants to be rigid and grow tall.

Chloroplasts

Organelles in plant cells that help plants make their food.

Meristems

Regions of rapidly dividing cells located at growing points, responsible for most plant growth.

Apical Meristems

Meristems located at root or shoot tips.

Intercalary Meristems

A special type of meristem found in grasses, allowing them to be mowed.

Secondary Meristems (vascular cambium)

Meristems responsible for making tree rings and expanding trunk diameter.

Epidermis

Outer tissue that allows for gas and water exchange through stomata.

STOMATA

Pores in the epidermis that allow for gas and water exchange.

TRICHOMES

Hairs or spines that may be present on the epidermis.

Periderm (bark)

An outer protective layer made from cork cells, providing extra protection to plants.

Cork

A material that comes from the bark of Quercus suber.

Suberin

A substance found in bark cells that repels water.

Phloem

Vascular tissue that moves food around plants; it is living and has fibers for strength.

Xylem

Vascular tissue that moves water up through the plant; it is dead when mature and forms the woody part of plants.

Roots

Plant organs that support/anchor the plant and take up water and nutrients.

Adventitious roots

Roots that arise from plant organs that are not roots, essential for some plant propagation.

Contractile roots

A type of root that can shorten to pull the plant deeper into the soil.

Brace or prop roots

Roots that provide extra support, common in plants like corn.

Holdfasts of vines

Roots that help vines attach to surfaces.

Tuberous roots

Thickened and fleshy roots specialized for storage, such as sweet potatoes or dahlias.

Stems

Plant organs characterized by nodes, internodes, and buds.

Nodes

Points on a stem where leaves or branches originate.

Internodes

Segments of a stem between nodes.

Buds

Compressed juvenile stems, most of which have scales.

Terminal Buds

Buds located at the very tip of a stem.

Axillary (lateral) Buds

Buds located in the axil of a leaf.

Alternate Bud Arrangement

A stem growth pattern with one bud per node.

Opposite Bud Arrangement

A stem growth pattern with two buds per node.

Tubers

Modified stems used for storage, such as potatoes.

Corms

Modified stems that are solid, swollen, and underground, like gladiolus or crocus.

Bulbs

Modified stems consisting mostly of fleshy leaves, such as tunicate (onion) or scaly (lily) types.

Rhizomes and stolons

Horizontal stems that grow underground (rhizomes) or along the surface (stolons).

Runners

Horizontal stems that typically grow along the ground surface.

Crown

The part of the stem of herbaceous perennials located near the soil surface, which can be divided for propagation.

Spur

A short stem on some fruit trees where flowers and fruit appear.

Suckers

Stems that grow at the base of a tree from adventitious buds.

Watersprouts

Stems that grow vertically up in the canopy of a tree from latent buds.

Tendrils

Modified stems or leaves that coil to help plants climb.

Thorns, spines, prickles

Modified stems or leaves that serve as protective structures.

Leaves

Plant organs where photosynthesis usually takes place.

Simple Leaf

A leaf where the blade is not divided into separate leaflets.

Compound Leaf

A leaf where the blade is divided into multiple leaflets.

Pinnate Venation

A leaf vein pattern where veins branch out from a central midrib, resembling a feather.

Palmate Venation

A leaf vein pattern where several main veins radiate from a single point, resembling a hand.

Palmatley compound leaf

A compound leaf where leaflets arise from a single point, with each leaflet having pinnate venation.

Pinnately compounded leaf

A compound leaf where leaflets are arranged along a central axis, with each leaflet having pinnate venation.

Bipinnately compound leaf

A compound leaf where the leaflets are further divided into smaller leaflets, meaning each leaflet is pinnately compound.

Evergreen needles

A type of leaf that can also be awl-like or scale-like, retained longer than typical broad leaves.

Upper epidermis

The top protective layer of a leaf.

Mesophyll

The middle layer of a leaf, containing the palisade and spongy layers.

Palisade layer

A layer of elongated cells in the mesophyll, densly packed for photosynthesis.

Spongy layer

A layer of irregularly shaped cells in the mesophyll with large air spaces, facilitating gas exchange.

Lower epidermis

The bottom protective layer of a leaf, often containing stomata.

Veins (leaves)

Vascular bundles within leaves that transport water, nutrients, and food.

Bracts

Modified leaves located right below a flower, which may be large and colorful (e.g., poinsettias).

Fall color

The phenomenon where chlorophyll is lost, and other pigments like xanthophyll, carotene, and anthocyanins become visible, often intensifying with sunny days and cool nights.

Xanthophyll

A yellow pigment that becomes visible in leaves during fall color.

Carotene

An orange pigment that becomes visible in leaves during fall color.

Anthocyanins

Red and purple pigments in leaves that intensify during fall color, especially with sunny days and cool nights.

Abscission (leaf falling)

The process of a leaf falling off, triggered by shorter days or stress, involving the formation of a suberin abscission layer.

Abscission layer

A layer formed by suberin at the base of the petiole that seals the wound, allowing the leaf to fall easily.

Juvenile plants

Plants that cannot flower even under the correct conditions, and may hold onto dried leaves through winter (e.g., oaks, beeches).

Phase change (plants)

The transition from a juvenile to a mature state in plants, triggered by age, size, or temperature.

Flowers

Reproductive organs of plants.

Corolla

The collective term for all the petals of a flower.

Calyx

The collective term for all the sepals of a flower.

Nectaries

Glands within flowers that produce nectar.

Complete flower

A flower that possesses all four main parts: calyx, corolla, pistil, and stamen.

Incomplete flower

A flower that is missing one or more of the four main parts: calyx, corolla, pistil, or stamen.

Perfect flower

A flower that has both sexual parts (pistil and stamen).

Imperfect flower

A flower that has only a pistil OR only a stamen, not both.

Regular flower

A flower that displays radial symmetry.

Irregular flower

A flower that displays bilateral symmetry.

Monoecious

A plant where one individual has both male and female flowers, or has perfect flowers.

Dioecious

A plant where one individual has ONLY male flowers or ONLY female flowers.

Inflorescence

The arrangement of flowers on a plant's stem.

Solitary Inflorescence

A single flower on a pedicel.

Spike Inflorescence

An inflorescence with sessile flowers arranged along an unbranched central axis.

Raceme Inflorescence

An inflorescence with flowers on short pedicels arranged along an unbranched central axis.

Panicle Inflorescence

A branched raceme, often with a pyramidal shape.

Corymb Inflorescence

A flat-topped inflorescence where the outermost flowers open first.

Cyme Inflorescence

A flat-topped inflorescence where the central flowers open first.

Umbel Inflorescence

An inflorescence with flower stalks of equal length originating from a common point.

Capitulum (composite head) Inflorescence

A dense cluster of small, sessile flowers, typical of the daisy family.

Fruits

A ripened ovary and/or associated parts of a flower, sometimes called the pericarp.

Pericarp

The wall of a fruit, developed from the ovary wall, consisting of three layers: exocarp, mesocarp, and endocarp.

Endocarp

The innermost layer of the pericarp.

Mesocarp

The middle layer of the pericarp.

Exocarp

The outermost layer of the pericarp.

Multiple fruits

Fruits formed from the fusion of several flowers during ripening, often having a core (e.g., pineapple, fig).

Aggregate fruits

Fruits formed from several ovaries produced by one single flower (e.g., raspberries, strawberries).

Simple Fruits

Fruits developed from a single flower with one pistil, categorized as either fleshy or dry.

Fleshy Fruits

Simple fruits that are soft, succulent, or fleshy when mature.

Berry

A fleshy fruit with one or more seeds embedded in a pulpy flesh (e.g., tomato, blueberry).

Pepo

A specialized berry with a thick, hard rind at maturity (e.g., squash, melons).

Hesperidium

A specialized berry with juicy, segmented flesh and a leathery rind (e.g., citrus fruits).

Drupe

A fleshy, one-seeded fruit distinguished by a stony endocarp (pit) surrounding the seed (e.g., cherry, plum).

Pome

A fleshy fruit where the endocarp is cartilaginous, forming a core (e.g., apple, pear).

Dry Fruits

Simple fruits that are not fleshy when mature, categorized as dehiscent or indehiscent.