Ovary (botany)
In the
Fruits
A
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
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.
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,
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.[13] 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.[13][14][15]
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.[13] Some fruits, like the apple, are accessory fruits which can include other parts of the flower such as the receptacle, hypanthium, perianth, or calyx in addition to the mature and ripened ovary.[16]
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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.
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Section of a raspberry flower
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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
Locules are chambers within the ovary of the flower and fruits. The locules contain the ovules (seeds), and may or may not be filled with fruit flesh. Depending on the number of locules in the ovary, fruits can be classified as uni-locular (unilocular), bi-locular, tri-locular or multi-locular. Some plants have septa between the carpels; the number of locules present in a gynoecium may be equal to or less than the number of carpels, depending on whether septa are present.
The ovules are attached to parts of the interior ovary walls called the placentae. Placental areas occur in various positions, corresponding to various parts of the carpels that make up the ovary. See
The ovary of some types of fruit is dehiscent; the ovary wall splits into sections called valves. There is no standard correspondence between the valves and the position of the septa; the valves may separate by splitting the septa (septicidal dehiscence), or by spitting between them (loculicidal dehiscence), or the ovary may open in other ways, as through pores or because a cap falls off.
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In this Peganum harmala, the ovary of a fruit has split into valves.
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The seeds in a tomato fruit grow from placental areas at the interior of the ovary. (This is axile placentation in a bi-locular fruit.)
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The placentae in Lunaria are along the margins of the fruit, where two carpels fuse. (This is parietal placentation in a bi-locular fruit.)
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The valves of Lunaria fruit fall to reveal a septum that was between the two carpels of the ovary.
Classification based on position
The terminology of the positions of ovaries is determined by the insertion point, where the other floral parts (
Superior ovary
A superior ovary is an ovary attached to the receptacle above the attachment of other floral parts. A superior ovary is found in types of fleshy fruits such as true berries, drupes, etc. A flower with this arrangement is described as hypogynous. Examples of this ovary type include the legumes (beans and peas and their relatives).
Half-inferior ovary
A half-inferior ovary (also known as “half-superior”, “subinferior,” or “partially inferior,”) is embedded or surrounded by the receptacle.
More specifically, a half-inferior ovary has nearly equal portions of ovary above and below the insertion point. Other varying degrees of inferiority can be described by other fractions. For instance, a "one-fifth inferior ovary" has approximately one fifth of its length under the insertion point. Likewise, only one quarter portion of a "three-quarters inferior ovary" is above the insertion.
Inferior ovary
An inferior ovary lies below the attachment of other floral parts. A
See also
- Fruit anatomy
References
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- ^ Gardocki, Mary; Zablocki, Heather; El-Keblawy, Ali; Freeman, D. (2000). "Heterocarpy in Calendula micrantha (Asteraceae): The effects of competition and availability of water on the performance of offspring from different fruit morphs". Evolutionary Ecology Research. 2: 701–718.
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- ^ a b c Guertin, P.; Barnett, L.; Denny, E.G.; Schaffer, S.N. (2015). USA National Phenology Network Botany Primer. USA-NPN Education and Engagement Series 2015-001. pp. 51–53.
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- ^ Hickey, M.; King, C. (2001), The Cambridge Illustrated Glossary of Botanical Terms, Cambridge University Press
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