A
fruit is the mature, ripened ovary of a flower following
double fertilization in an
angiosperm. Because
gymnosperms do not have an ovary but reproduce through fertilization of unprotected
ovules, they produce naked
seeds that do not have a surrounding fruit. For this reason,
juniper and
yew "berries" are not fruits, but modified
cones. Fruits are responsible for the dispersal and protection of seeds in angiosperms, and cannot be easily characterized due to the differences in culinary and botanical definitions of fruits.
Development After double fertilization and ripening, the ovary becomes the fruit, the ovules inside the ovary become the seeds of that fruit, and the egg within the ovule becomes the
zygote. Double fertilization of the
central cell in the ovule produces the nutritious
endosperm tissue that surrounds the developing zygote within the seed.
Dispersal and evolutionary significance Fruits are important in the dispersal and protection of seeds, and variation in fruit shape or size results from an evolutionary response that aids in the dispersal of seeds in different environments. For example, the seeds of large fleshy fruits are often dispersed through
endozoochory; this means that animals consume the fleshy fruit and as a result disperse its seeds with their movement. The seeds of fruits can be dispersed by endozoochory, gravity, wind, or other means.
Complications and types of fruits There are some complications to the definition of a fruit, as not all botanical fruits can be identified as culinary fruits. A ripened ovary may be a fleshy fruit such as a grapefruit or a dry fruit such as a nut. Further complicating this,
culinary nuts are not always
botanical nuts; some culinary nuts such as the coconut and almond are another type of fruit called a
drupe. In this same way, not all "fruits" are true fruits. A true fruit only consists of the ripened ovary and its contents. Fruits can be separated into three major categories:
simple fruits,
aggregate fruits, and
multiple fruits. Simple fruits like oranges are formed from a single ovary which may or may not consist of multiple parts, while aggregate and multiple fruits are formed from several ovaries together. Aggregate fruits like raspberries are the ripened ovaries of one flower that form a single fruit, and multiple fruits like pineapples are formed from the ovaries of separate flowers that are close together. Because aggregate and multiple fruits are formed from many ripened ovaries together, they are actually
infructescences or groups of fruits that are arranged together in a structure. File:Raspberries (Rubus Idaeus).jpg|The raspberry is an aggregate fruit. Each raspberry develops from one flower, but its flower has many ovaries that become the small circular
drupes making up the raspberry. There is a seed in each drupe. File:Longitudinal_section_of_raspberry_flower.gif|Section of a raspberry flower File:Pineapple flower in Thailand.jpg|The pineapple is a multiple fruit. Each of the purple spikes in this picture are a separate flower, so the whole structure is an
inflorescence. This means that the small sections of a pineapple are each a fruit that develop from a separate ovary, and together they make up a multiple fruit. == Parts of the ovary==