As a capsule fruit is referred to in the Botany a fruit type with an ovary from a plurality of fused carpels (carpels). There can be more or less chambered and non-chambered ovaries. Capsule fruits belong to the group of scattered fruits that open (dehiscence) and thus release the seeds .
The opening points or lines (dehiscence points or lines) are pre-formed in the ovary. They open through the lignification or drying of the pericarp . The resulting flaps (valves) shrink and the gap that forms in the scar region continues to widen. This also allows the flaps to curve outwards. The columella sometimes prevents the fruit from completely disintegrating, since the partitions (septa) that have grown together do not separate.
Consequently, capsule fruits mostly belong to the dried fruits. Fleshy capsule fruits occur mainly in the tropics, examples of the European flora are the spring herbs or the spindle bushes and aesculus . In contrast to the usual dry forms, they are called juice capsules . Capsule fruits occur in almost all plant families , but they are absent in the rose family , the butterflies and the daisy family .
The valves , flaps of the capsule and other scattered fruits are not to be confused with those of the plant genus Dock → Valven , the three inner tepals here form wings that envelop the fruit. Even with anthers that open by folding one speaks of Valven.
Classification of the capsule fruits
The naming and further subdivision of the capsule fruits is based on the type of opening.
Pore capsule and derived forms
Pore capsules , perforated capsules or poricidal capsule fruits (poricidal or inoperculate or poricidal-operculate; pores with a flap, lid - operculum) can only be found in a few genera, they are particularly typical for snapdragons or bluebells , the best-known example is the poppy . The Valven dissolve therein is very limited downwards, hence there are no full Dehiszenzlinien but per carpel a clear-cut opening in the capsule wall, to be released by the seeds exactly. The pores remain laterally separated from each other by the remains of the placenta and the carpel margins. The pores are arranged in a circular line around the capsule.
In the pentameric fruit of the prickly poppy species , a transition to the pod fruit type can be seen. If the valves initially detach only a little from the ripe ovary, the fruit is reminiscent of a pore capsule made up of five carpels with corresponding five pores. If they become detached with increasing fruit ripeness, a framework-like frame (replum) remains in the distal area, which is why one speaks of a rather rare frame capsule . But it also occurs in other species such as B. in Aristolochia or Chelidonium .
The pod of cruciferous Although considered as a separate type of fruit, but it is a special form of capsule fruit. If you reduce the frame capsule to two carpels, you get a pod. A replum from the united carpel margins and their placenta remains here, since the valves completely detach. A false partition is stretched in the frame. This form of fruit is also rarely referred to as a window capsule .
A lid capsule , also called pyxidium , opens all around (circumsessile, pyxidial) through a lid (operculum, operculate), which covers the seed chambers of the capsule fruit. Lid capsules occur in at least 17 plant families, including the amaranthaceae (Amaranthaceae), Barberry (Berberidaceae), Cucurbitaceae (Cucurbitaceae), lecythidaceae (Lecythidaceae), Myrtle (Myrtaceae), Plantain Family (Plantaginaceae) and the nightshade family (Solanaceae). In the carnivorous species Genlisea hispidula , a pericarp ring is deposited due to an additional caesura , and the dehiscence line can continue to be screwy.
Poricide-operculate pore capsule of a poppy plant
Poricidal capsule fruit of Antirrhinum majus
Immature, prickly frame capsule of the Mexican prickly poppy . The bluish lines indicate the remaining frame
Frame capsule from Argemone ochroleuca
Lidded capsules and seeds of the common plantain
Lid capsule of Amaranthus blitoides
Lidded or tooth capsules of Eucalyptus tereticornis
Split capsules are the most common form of the capsule fruit. The capsule opens through longitudinal cracks (dehiscence lines) to release the seeds. Often the capsule fruit opens over the entire length of the pericarp. The different opening options also occur in combination . Since the fruit does not completely disintegrate, it must not be called a split fruit .
Ventricidal capsule fruit
If the opening lines are on the ventral side of the individual carpels , one speaks of a ventricidal or ventricidal capsule fruit. This can only arise in apocarpic gynoeceum from non-fused carpels, since the ventral side of the carpels is lost as a result of the adhesion. A completely coenocarpes gynoeceum cannot form ventricidal capsule fruits, a gynoeceum that is only partially fused with apocarp can only produce this proportion accordingly. As with the common pimpernut , it can be short or, as with the diptam , it can exceed the basal, fertile, coenocarpic part in size.
The pelvic fruit is often very similar.
Loculicidal capsule fruit
If the outer central ribs of each individual carpel burst when ripe, it is called a dorsic or dorsicidal capsule fruit. This opens the seed-bearing compartments, called loculaments or loculi, of each carpel individually. This results in the more common term columnar or loculicidal (loculicidal) capsule fruit. Loculicidal capsule fruits are found in irises , daffodils and evening primrose . Many lily plants such as tulips , onions , lilies and grape hyacinths also have such split capsules. The best-known loculicidal capsule fruit is that of cotton . Many single-celled seed hairs swell from the capsule fruit of the cotton when it is opened .
Septicidal capsule fruit
If the capsule fruit tears open lengthways along the sutures and / or on the septa of the carpels, then there is a septicidal or septicidal capsule fruit. A coenocarpes gynoeceum can only release the semen if there is a small paracarpic portion, otherwise there is no gaping opening. Septicidal capsule fruits occur in St. John's wort , alpine roses or orchids .
Also possible are septicidal-ventricidal capsule fruits which open at the septa and the ventral sides ( Altingiaceae ). And septicidal-loculicidal capsule fruits are also possible. B. in the cassava and wightia . Such capsule fruits, which open in two different ways, are also known as bicidal . A tricial opening is also possible, as in the case of the euphorbias , septicidal-loculicidal-septifrage .
In addition to the dehiscence lines along the carpels, transverse breaks can occur at the septa where the valves break off. Fruits of the septum or septum fragments form (septifragal, valvular). However, this form of dehiscence only occurs in combination with a septicide or a loculicide. Septicidal-septifrage (marginicidal) capsule fruits can be found in Paullinia , Calluna and Rhododendron , loculicidal-septifrage capsule fruits in Epilobium and Datura .
The foraminicidal , denticidal and fissuricidal capsule fruits of some species have a special shape . The fissuricidal capsule fruits open irregularly through one or more parallel slits, or regularly along cracks between the tip and the base, as with the orchids . In the case of denticidal capsule fruits, several narrow, ring-shaped teeth (tooth capsules) open at the tip, as in the carnation family . Foraminicidal capsule fruits open irregularly or abnormally (anomalicidal, tearing) through several cracks or slits in different directions e.g. B. in Genlisea and Cuscuta . These special forms are used by some authors. Furthermore, there are capsule fruits that break open due to expanding, enlarging seeds, which are to be delimited (Glandispermidium) ( Ophiopogon ).
A distinction can also be made between an apical (acrocidal) or basal (basicidal) opening of a capsule fruit, as in Aristolochia .
Denticidal or apical capsule fruit of the white carnation
The “coccum” is also a special form, it is formed from just one carpel and opens along two seams, it stands between an opening stone fruit or a capsule and a legume. Also because the term legume stands for the fruits of legumes, a differentiation is necessary. It comes z. B. in the nutmeg family and in the silver tree .
There are capsule fruits that do not or rarely open and are only opened by animals chewing or biting or by "falling to the ground" (some Gardenia , Alphitonia , Merciera and Adansonia species, among others).
"Wing capsules" are also possible, here the capsule fruits are winged.
Other capsule-shaped structures which enclose the seeds and fruits are to be defined. They are formed from fore , bracts and sepals or others, as in the case of the helmet herbs , Physalis , Carex or Allocasuarina and in wing fruits or capsules, as well as in berry cones. In the case of the eucalyptus , the capsule fruit is formed by the ovary that has grown together with the base of the flower ; it is therefore one of the lid or tooth capsule.
- Focko Weberling : Morphology of the flowers and the inflorescences. Verlag Eugen Ulmer, Stuttgart 1981, ISBN 3-8001-3426-8 .
- Wilhelm Troll : Practical introduction to plant morphology. Second part: the flowering plant. Gustav Fischer Verlag, Jena 1957.
- Peter Sitte , Elmar Weiler , Joachim W. Kadereit , Andreas Bresinsky , Christian Körner : Textbook of botany for universities . Founded by Eduard Strasburger . 35th edition. Spektrum Akademischer Verlag, Heidelberg 2002, ISBN 3-8274-1010-X .
- Wilhelm Troll : Practical introduction to plant morphology. Second part: The blooming plant , Gustav Fischer Verlag, Jena 1957 p. 65 f.
- Peter Sitte , Elmar Weiler , Joachim W. Kadereit , Andreas Bresinsky , Christian Körner : Textbook of botany for universities . Founded by Eduard Strasburger . 35th edition. Spektrum Akademischer Verlag, Heidelberg 2002, ISBN 3-8274-1010-X , p. 780 .
- Troll: p. 68.
- Sitte et al .: p. 779.
- Fruit Types at Northern Ontario Plant Database, accessed August 2, 2018.
- Troll: p. 69 f.
- Troll: p. 70 ff.
- Troll: p. 69 ff.
- J. R. Hoppe: Lecture script general botany. Part II, online (PDF), at biologie.uni-ulm.de, accessed on August 22, 2008.
- Richard W. Spjut: A Systematic Treatment of Fruit Types , The World Botanical Associates Web Page, accessed on 9 April of 2008.
- Focko Weberling : Morphology of the flowers and the inflorescences. Verlag Eugen Ulmer, Stuttgart 1981, p. 350.
- Sitte et al .: p. 780.
- Weberling: p. 152.
- Ann-Katrin Müller: Gossypium spec. - The cotton at Uni Marburg, accessed on August 3, 2018.
- SM Ickert-Bond, KB Pigg, J. Wen: Comparative infructescence morphology in Altingia (Altingiaceae) and discordance between morphological and molecular phylogenies. In: Am. J. Bot. 94 (7), 2007, pp. 1094-115, doi: 10.3732 / ajb.94.7.1094 .
- Maarten JM Christenhusz, Michael F. Fay, Mark W. Chase: Plants of the World. Kew Pub., 2017, ISBN 978-1-84246-634-6 , p. 581.
- Carlos E. Dominguez et al. a .: Morphology of the cassava plant. CIAT, 1984, p. 17 ff.
- Famille des Euphorbiaceae on plantes-botanique.org, accessed August 7, 2018.
- Weberling: p. 350.
- William Baker Day: A Revision of Bastin's College Botany. Second Edition, Engelhard, Chicago 1927, pp. 119 ff, online at babel.hathitrust.org, accessed on August 3, 2018.
- OP Pareek, Suneel Sharma: Systematic pomology. Vol. 1-2, Scientific Pub., 2017, ISBN 978-93-86102-81-2 (set), p. 595.
- Wolfgang Stuppy: Glossary of Seed and Fruit Morphological Terms - Kew Gardens. 2004, online ( Memento of the original dated August 2, 2018 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. (PDF).
- Michael G. Simpson: Plant Systematics. Academic Press, 2006, ISBN 0-12-644460-9 , pp. 384 f.
- John Lindley: An Introduction to Botany. Volume 2, 4th edition, London 1848, p. 23.
- Samuel F. Gray : Natural Arrangement of British Plants. Vol. 1, London 1821, p. 185.
- Fruit Terminology Part 1 at Palomar College, accessed August 2, 2018.
- Merciera at Plantz Africa, accessed on August 2, 2018.
- S. Manchester, EL O'Leary: Phylogenetic Distribution and Identification of Fin-winged Fruits. In: The Botanical Review. 76 (1), 2010, pp. 1–82, doi: 10.1007 / s12229-010-9041-0 , online (PDF; 3.3 MB), on researchgate.net, accessed on August 6, 2018.