A Glossary of Terms from Lab 8:

anther
The terminal pollen sac of a stamen, inside which pollen grains with male gametes form in the flower of an angiosperm.

angiosperms
Any plant that is a member of the class Angiospermae, in which the seeds are enclosed in an ovary. Each member of the class is either a monocotyledon (grasses, tulips) or a dicotyledon (apple, primrose).

antipodal
The three haploid nuclei which are formed during megasporogenesis in plants. They are all located opposite the micropyle end of an ovule.

archegonium (pl. archegonia)
The female sex organ of liverworts, mosses, ferns, and most gymnosperms. It isusually a flask-shaped organ, comprising a swollen base or venter containing asingle egg-cell and a slender elongated neck containing one or more layers ofcells.

bract
A modified leaf with a single flower growing in its axil

calyx
A collective term for all the sepals of a flower.

carpel
The female reproductive organ of a flower, consisting of the stigma, style and ovary.

central cell
Found in the central region of the megagametophyte, it contains two polar nuclei.

corolla
A collective term for all the petals of a flower. The petals are often brightly coloured and attract pollinating animals. The corolla encloses the reproductive organs, and is itself protected by the sepal.

cotyledons
The one (monocot) or two (dicot) seed leaves of an angiosperm embryo.

dehiscent
Will spontaneously burst open to release it's contents, usually spores or seeds.

determinate growth
A type of growth characteristic of animals, in which the organism stops growing after it reaches a certain size.

embryo sac
The female gametophyte of angiosperms, formed from the growth and division of the megaspore into a multicellular structure with eight haploid nuclei.

endosperm
A nutrient-rich tissue formed by union of a sperm cell with two polar nuclei during double fertilization, which provides nourishment to the developing embryo in angiosperm seeds.

flower
A structure involved in sexual reproduction. It consists of the androecium (male organs) and gynoecium (female organs), surrounded by a corolla and a calyx. The male and female parts may or may not be in the same flower.

funiculus
The stalk by which a developing angiosperm ovule attaches to the carpel wall.

generative cell
One of two haploid nuclei found within pollen grains of flowering plants, which enters the pollen tube when it is produced, divides by mitosis, and becomes the male gamete nucleus that fuses with the female egg cell at fertilization.

gametophyte
The part of the life cycle of plants having haploid nuclei and giving rise to the sex cells that on fusing produce a diploid stage, usually the sporophyte.

gymnosperm
A vascular plant that bears naked seeds not enclosed in any specialized chambers.

gynoecium
The female reproductive organs of a flower, consisting of one or more carpels.

heterosporous
The formation of more than one sort of spore, usually microspores and megaspores in ferns and seed plants, giving rise to distinct male and female gametophyte generations.

indehiscent
Will not spontaneously burst open to release it's contents, usually spores or seeds.

inflorescence
A specialized branching stem bearing more than a single flower, for example, a male catkin.

integument
The outermost layer or layers of tissue that serve in protection.

megagametophyte
Female gametophyte

megasporangium
The organ in which megaspores are formed.

megaspore
The larger of two types of spores produced by many ferns and seed plants. The megaspore gives rise to a female gametophyte in ferns and in seed plants, and in flowering plants becomes the embryo sac.

megasporocyte
Special cell of the megasporangium called the megaspore mother cell.

meristem
A region of a plant in which active cell division occurs, the cells of the meristem being undifferentiated into a specialized form. Meristematic tissues occur at the root and shoot tips giving growth in length.

microgametophyte
Pollen grains.

micropyle
A small canal in the integument surrounding the ovule of a flowering plant, through which the pollen tube usually enters the ovule on the way to the embryo sac. Water enters the seed via the micropyle prior to germination.

microsporangium
The sporangium from which the microspores are formed, which in higher plants is the pollen sac.

microspore
The smaller of the two types of spore produced by ferns and higher plants, giving rise to the male gametophyte. In Tracheophytes the microspore is the pollen grain.

microsporocytes
Thousands of cells (pollen mother cells) found within a young microsporangium.

ovary
(1) in flowers, the portion of a carpel in which the egg-containing ovules develop. (2) in animals, the structure that produces female gametes and reproductive hormones.

ovule
A structure found in higher plants that contains an egg cell and develops into a seed after fertilization.

ovuliferous scales
A spiral series of overlapping scales making up the female or ovulate cone with each scale producing two ovules on the upper surface.

petal
Any of the separate parts of the corolla of a flower. Often brightly colored, the petal is a modified leaf and is important in flowers pollinated by insects.

pistil
The flask-shaped female reproductive unit of a flower, composed of ovary, style, and stigma.

polar nuclei
The two nuclei that are formed at each pole of the angiosperm embryo sac. They will fuse with a male nucleus to form a primary endosperm nucleus.

pollen grain
A small structure of higher plants that contains haploid male gamete nuclei and is surrounded by a double wall, the exine and intine. Pollen grains are transported from the male stamen to the female stigma in a process called pollination.

pollen tube
A slender structure produced from a pollen grain after pollination.

receptacle
1. in flowering plants, the end of the stalk becoming the flower parts. 2. in ferns, the mass of tissue that becomes the sporangium. 3. in liverworts, the cup containing a gemma. 4. in algae, the swollen tip of a branch carrying the reproductive organs.

root
The part of a plant that usually grows below ground. The root provides anchorage for aerial parts, absorbs water and mineral salts from the soil, conducts water and nutrients to other parts of the plant, and often stores food materials over winter.

root cap
A structure found at the apex of roots, except those of many water plants, produced by the apical meristem. As the root pushes its way through the soil, the outer (older) cells of the root cap are sloughed off and replaced by new cells from the meristem.

seed
Formed from a fertilized ovule, it is the body from which a new plant develops. It is comprised of an outer coat enclosing a food source (which may be stored in the cotyledon), and an embryo.

seed coat
A protective coat around the seed, formed from the integuments of the ovule.

seed plant
A plant that bears seeds. Most seed plants, have flowers and produce seeds in fruits; some, such as the pines, form seeds on cones.

sepal
A whorl of modified leaves in angiosperms that encloses and protects the flower bud before it opens.

shoot
The part of a vascular plant above the ground, consisting of stem and leaves.

spore
In the life cycle of a plant or alga undergoing alternation of generations, a meiotically produced haploid cell that divides mitotically, generating a multicellular individual, the gametophyte, without fusing with another cell.

sporophyte
The multicellular diploid form in organisms undergoing alternation of generations that results from a union of gametes and that meiotically produces haploid spores that grow into the gametophyte generation.

stamen
The pollen-producing male reproductive organ of a flower, consisting of an anther and filament.

sterile cell
A cell derived from the microgametophyte which does not divide further.

stigma
The part of the reproductive organs of flowers where pollen grains germinate.

style
The slender, neck-like portion of the carpel that leads to the ovary.

synergid
Either of two small cells present in the embryo sac of seed plants near the egg cell at the micropylar end.

syngamy
The process of cellular union during fertilization.

tube cell nucleus
One of two haploid nuclei within a developing pollen tube, whose function may be control of tube growth.

zygote
The diploid product of the union of haploid gametes in conception; a fertilized egg.