Biology Chapter 38

anther

The terminal pollen sac of a stamen, inside which pollen grains with male gametes form in the flower of an angiosperm. Each anther bears four microsporangia, also known as pollen sacs. Within the microsporangia are many diploid cells called microsporocytes, also known as microspore mother cells.

Angiosperm gametophytes

are the smallest of all plants, consisting of only a few cells.

Angiosperm

flowering plant; bears its seeds within a layer of tissue that protects the seed

inflorescences

flowers grouped in clusters

aggregate fruit

fruit consisting of many individual small fruits or drupes derived from separate ovaries within a common receptacle: e.g. blackberry

ovule

megasporangia; has sporocytes that undergo meosis, only one survives

petals

modified leaves which are usually bright in color to attract pollinators.

endosperm

nutritive tissue surrounding the embryo within seeds of flowering plants;2nd sperm combines with 2 polar nuclei to form triploid (3n )nucleus in the central cell of the female gametophyte.

stigma

the apical end of the style where deposited pollen enters the pistil

pistil

the female ovule-bearing part of a flower composed of ovary and style and stigma

imbibition

the uptake of water due to the low water potential of the dry seed

accessory fruits

(1) a fruit in which some of the flesh is derived not from the ovary but from some adjacent tissue, fig, apple

multiple fruit

A fruit derived from an inflorescence, a group of flowers tightly clustered together., pineapple

fragmentation

A means of asexual reproduction whereby a single parent breaks into parts that regenerate into whole new individuals.

Double Fertilization

A mechanism of fertilization in angiosperms, in which two sperm cells unite with two cells in the embryo sac to form the zygote and endosperm.After double fertilization, the ovule develops into a seed, and the ovary develops into a fruit enclosing the seed(s).

coleoptile

A protective sheath covering the embryonic shoot

megaspores

A spore from a heterosporous plant that develops into a female gametophyte bearing archegonia.

microspores

A spore from a heterosporous plant that develops into a male gametophyte with antheridia. Each microspore then undergoes mitosis to produce an immature male gametophyte consisting of only two cells: the generative cell and the tube cell. each microspore will make the pollen grain.

female gametophyte 2

As the surviving megaspore grows, its nucleus divides by mitosis three times without cytokinesis, resulting in one large cell with eight haploid nuclei. 2 cells are called synergies; guide pollen tube to embryo sac antipodal cells are found opposite of embryo of unknown function The remaining two nuclei,called polar nuclei, are not partitioned into separate cellsbut instead share the cytoplasm of the large central cell of the embryo sac. The ovule, which will eventually become a seed, ovary the fruit

male gametophyte

Each anther bears four microsporangia, also known as pollen sacs. Within the microsporangia are many diploid cells called microsporocytes Each microsporocyte forms four haploid microspores by meiosis. Each microspore then undergoes mitosis to produce an immature male gametophyte consisting of only two cells: the generative cell and the tube cell, called pollen grain

biofuels

Fuels, such as ethanol or methanol, that are created from the fermentation of plants or plant products.

sepals

Leaflike parts that cover and protect the flower bud

dioecious

Separate male and female plants plants that cannot self-fertilize because different individuals have either staminate (lacking carpels) or carpellate (lacking stamens) flowe

ovules

The female part of the flower, which produces the eggs that are needed for making seeds

carpels

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

similarities bw animals and plants

The first cellular event after gamete fusion is an increase in cytoplasmic Ca2+ levels, which also occurs during animal gamete fusion. In another similarity to animals, plants establish a block to polyspermy, the fertilization of an egg by more than one sperm cell. o In plants, a deposition of cell wall material may mechanically impede sperm.

protoplast fusion

The fusing of two protoplasts from different plant species that would otherwise be reproductively incompatible.

generative cell

The nucleus of the generative cell divides by mitosis to produce two sperm, one for egg and one for endosperm

stamens

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

vegetative reproduction

Type of reproduction in which new plants grow from vegetative parts such as roots, stems, and leaves

microsporocyte

Within the microsporangia are many diploid cells called microsporocytes, also known as microspore mother cells. Each microsporocyte forms four haploid microspores by meiosis.

incomplete flowers

a flower in which one or more of the four basic floral organs are either absent or nonfunctional

Complete flowers

a flower that has all four basic floral organs: sepals, petals, stamens, and carpals

dormancy

a state in which seeds, spores, bulbs, and other reproductive organs stop growth and development and reduce their metabolism, especially respiration

apomixis

any of several kinds of reproduction without fertilization

self-incompatibility

bisexual flowers the ability of a seed plant to reject its own pollen and sometimes the pollen of closely related individuals. For example, in some species, stamens and carpels mature at different times. flowers may be arranged in such way that it is mechanically unlikely that an animal pollinator could transfer pollen from the anthers to the stigma of the same flower.

scion

detached plant shoot used in grafting; descendant

simple fruits

develop from a single ovary and at least one of the layer is fleshy and juicy (ex. peaches and tomatoes)

embryo sac

female gametophyte within the ovule of a flowering plant

female gametophyte

female gametophyte, also known as an embryo sac The development of the embryo sac occurs within the carpel's ovary, in the tissue within each ovule called the megasporangium. Two integuments (layers of protective sporophytic tissue that eventually develop into the seed coat) surround each megasporangium except at a gap called the micropyle. The megasporocyte in the megasporangium of each ovule enlarges and undergoes meiosis, producing four haploid megaspores. Only one megaspore survives

transgenic

genetically modified (GM) organisms that have been engineered to express a gene from another species

microsporocyte

in the microsporangia gives rise to 4 microspores

radicle

part of the seed that becomes the root

Protoplasts

plant cells that have had their cell walls removed enzymatically by fungal cellulases and pectinases.

coevolution

process by which two species evolve in response to changes in each other

coleorhiza

protective covering in a monocot seed over the root

asexual reproduction

reproduction without the fusion of gametes

pollen tube

slender tubular outgrown from a pollen grain that penetrates the ovule and releases male gametes comes from the tube cell

seed coat

structure that surrounds and protects a plant embryo and keeps it from drying out

receptacle

the base of a flower; the part of the stem that is the site of attachment of the floral organs.

pollen

the fine spores that contain male gametes and that are borne by an anther in a flowering plant

style

the narrow elongated part of the pistil between the ovary and the stigma

ovary

the organ that bears the ovules of a flower

hypocotyl

the part of a plant embryo directly below the cotyledons, forming a connection with the radicle.

epicotyl

the portion of the stem of a plant embryo that is between the cotyledons and the first true leaves

fruit

the ripened reproductive body of a seed plant

pollination

the transfer of pollen from male reproductive structures to female reproductive structures in plants