Plants

cotyledon

the first leaf that appears on an embryo of a flowering plant; a seed leaf

monocot

embryo with one seed leaf

dicot

embryo with two seed leaves

organ

several types of tissues that together carry out particular function

root system

anchors the plant in the soil, absorbs and transports minerals and water, and stores food

root hairs

tiny tubular projections that enormously increase the root surface area for absorption of water and minerals

shoot system

made up of stems, leaves and adaptations for reproduction, which in angiosperms are flowers

stems

part of the plant that are generally above the ground that support and separate the leaves

nodes

the points at which leaves are attached

internodes

portions of the stem between nodes, which are the points at which leaves are attached

leaves

main photosynthetic organs in most plants

terminal bud

embryonic tissue at the tip of a shoot, made up of developing leaves and a compact series of notes and internodes

axillary buds

an embryonic shoot present in the angle formed by leaf and stem

apical dominance

in a plant, the hormonal inhibition of axillary buds by a terminal bud

rhizomes

large, brownish, rootlike structures, horizontal stems that grow near the soil surface, store food and can form new plants because they have buds

tubers

an enlargement at the end of a rhizome in which food is stored, i.e.: potato

tissue

group of cells that together perform a specialized function

xylem

tissue that contains water-conduction cells that convey water and dissolved minerals upward from the roots

phloem

tissue that contains cells that transports sugars and other organic nutrients from leaves or storage tissues to other parts of the plant

tissue system

tissue that contains cells that transports sugars and other organic nutrients from leaves or storage tissues to other parts of the plant

dermal tissue system

plant's outer protective covering, forms the first line of defense against physical damage and infectious organisms, consists of a single layer of tightly packed cells (epidermis)

epidermis

tightly packed cells in dermal tissue system

cuticle

helps prevent water loss, waxy coating belonging to leaves and stems

ground tissue system

tissues that are neither dermal nor vascular, accounts for most of the bulk of a young plant, filling the spaces between the epidermis and vascular tissue system

pith

ground tissue internal to the vascular tissue

cortex

ground tissue external to the vascular tissue

vascular cylinder

the central cylinder of vascular tissue in a plant root

endodermis

the innermost layer of the cortex, a cylinder one cell thick, selective barrier, determining which substances pass between the rest of the cortex and the vascular tissue

vascular bundles

a strand of vascular tissues (both xylem and phloem) in a plant stem

stomata

tiny pores which allow exchange of CO2 and O2 between the surrounding air and the photosynthetic cell inside the leaf

guard cells

2 flank the stoma, regulate the opening and closing of the stoma

mesophyll

ground tissue system of a leaf, sandwiched between the upper and lower epidermis, consists mainly of cells specialized for photosynthesis

vein

vascular bundle composed of xylem and phloem tissues surrounded by a protective sheath of cells

parenchyma cells

most abundant type of cell in plants, usually have only primary cell walls (thin and flexible), perform most metabolic functions of a plant, such as photosynthesis, aerobic respiration, food storage, can divide and differentiate into other types of plant cells under certain conditions

sclerenchyma cells

have thick secondary cell walls usually strengthened with lignin, the main chemical component of wood, mature cells cannot elongate and are thus only found in regions of the plant that have stopped growing in length

fiber

type of sclerenchyma cells, long and slender and is usually arranged in bundles

tracheid

tapered, porous, water-conducting, and supportive cell in plants, make up the water-conducting tubes in xylem

vessel elements

wide, short, less tapered supportive cells, make up supportive and water-conducting tubes in xylem

sieve-tube elements

food conducting cells in plants, chains make up phloem tissue

companion cell

a cell connected to a sieve-tube element whose nucleus and ribosomes provide proteins for the sieve-tube element

determinate growth

termination of growth after reaching a certain size

indeterminate growth

growth that continues throughout life, as in most plants

annuals

plants that complete its life cycle in a single year or growing season

biennials

plants that complete its life cycle in two years

perennials

a plant that lives for many years

meristem

plant tissue consisting of undifferentiated cells that divide and generate new cells and tissues

apical meristem

plant tissue made up of undifferentiated cells located at the tip of a plant root or in the terminal or axillary bud of a shoot, enable roots and shoots to grow in length

primary growth

growth in the length of a plant root or shoot, produced by apical meristems

secondary growth

an increase in a plant's diameter, involving cell division in the vascular cambium and cork cambium

lateral meristems

plant tissue made up of undifferentiated cells that enable roots and shoots of woody plants to thicken, includes vascular and cork cambium

vascular cambium

during secondary growth of a plant, the cylinder of meristematic cells, surrounding the xylem and pith, that produces secondary xylem and phloem

secondary xylem

derived from the vascular cambium in plants exhibiting secondary growth

bark

all the tissues external to the vascular cambium in a plant that is growing in thickness, made of of secondary phloem, cork cambium and cork

heartwood

in the center of trees, the darkened, older layers of secondary xylem made up of cells that no longer transport water and are clogged with resins

sapwood

light-colored, water-conducting secondary xylem in a tree

sepals

modified leaves of a flowering plant, a whorl encloses and protects the flower bud before it opens

petals

modified leaves of a flowering plant, often colorful parts of a flower that advertise it to pollinators

stamen

a pollen-producing male reproductive part of a flower, consisting of a filament and anther

anther

a sac located at the tip of a flower's stamen, contains male sporangia in which meiosis occurs to produce spores that form the male gametophytes, or pollen grains

carpel

the female part of the flower, consisting of a stalk with an ovary at the base and a stigma, which traps pollen, at the tip

stigma

the sticky tip of a flower's carpel, which attracts pollen grain

ovary

the basal portion of a carpel in which the egg-containing ovules develop

ovules

a structure that develops within the ovary of a seed plant and contains the female gametophyte

pistil

part of the reproductive organ of an angiosperm, a single carpel or a group of fused carpels

germinate

to start developing or growing

gametophyte

the multicellular haploid form in the life cycle of organisms undergoing alternation of generations

pollination

in seed plants, the delivery by wind or animals of pollen from the pollen-producing parts of a plant to the stigma of a carpel

endosperm

a thick-coated, protective cell produces within a bacterial cell, becomes dormant and is able to survive harsh environmental conditions

seed coat

a tough outer covering of a seed, formed from the outer coat (integuments) of an ovule --> in flowering plants, it encloses and protects the embryo and endosperm

fruit

a ripened, thickened ovary of a flower, which protects developing seeds and aids in their dispersal

primary xylem

derived from the procambium