Exercise 13: Seed and Seed Dispersal

Seed

mature ovule that consists of an embryo and endosperm

Embryo

tiny plant that the seed contains

Endosperm

contains food reserved, nourishes the development of zygote

Cotyledon

seed leaf

Radicle

primordial root or baby root

Epicotyl

primordial stem that will become shoot, leaves, and stems

Hypocotyl

Root/shoot junction or the connection between cotyledon and radicle

Testa

protective layer on the outside of a bean seed which is usually very thin but tough

Micropyle

Within the surface of the testa, there is a tiny opening which is where water can enter and start the germination process breaking the dormant stage

Tegmen

thin, papery layer in the testa

Hilum

scar on a bean is the site where the bean originally attached to the fruit of the plant

Monocot

__________ are mostly endospermic

Orchids

monocot seeds where seeds are non-endospermic

Grain

maize seed coat is fused with fruit coat in cereals

Pericarp

seed coat in cereals

Endosperm

separate part of storage of starch develops

Aleurone Layer

proteinaceous layer that separates the embryo and endosperm

Albuminous Seeds

seeds in which endosperm is present and provides nutrition during the early development of the seed wherein the cotyledons are thin and membranous

cotton

examples of dicot albuminous seed

maize, wheat, rice

examples of monocot albuminous seed

Exalbuminous Seeds

seeds in which endosperm is absent, and food is stored in fleshy and thick cotyledons

pea, bean, gram

examples of dicot exalbuminous seeds

orchid

examples of monocot exalbuminous seeds

Seed DIspersal

Transfer of fruits/seeds from one place to another; Colonize new suitable habitat; Avoid pathogens and predator; Minimize in-breeding

Insect in Seed Dispersal

much less important for dispersal than pollination

ants

examples of insects used in seed dispersal

Animal in Seed Dispersal

much more important for dispersal than pollination

Wind

important in both pollination and dispersal

Water

minor importance in pollination, somewhat greater in dispersal

Zoochory

Agents of Seed Dispersal: Animals

Epizoochory

Agents of Seed Dispersal: Attached to Animal

Endozoochory

Agents of Seed Dispersal: Eaten by the Animal

Omithochory

Agents of Seed Dispersal: Birds

Mammaliochory

Agents of Seed Dispersal: Mammals

Chiropterochory

Agents of Seed Dispersal: Bats

Myrmecochory

Agents of Seed Dispersal: Ants

Anemochory

Agents of Seed Dispersal: Wind

Hydrochory

Agents of Seed Dispersal: Water

Autochory

Agents of Seed Dispersal: Dispersal by the Plant itself