Abortive flower

Abortion in flowers and developing fruits is a common occurrence in plants. ^[1]

An abortive flower ^[2] is one that possesses stamens but has an underdeveloped or absent pistil, preventing it from developing into fruit. ^[3] This phenomenon can occur naturally due to developmental, genetic, or environmental factors. Abortive flowers are often sterile or non-functional in reproduction, though they may still play ecological roles.

Sexual reproduction in flowering plants typically requires both male (stamens) and female (pistils) organs, though many species produce unisexual flowers or rely on cross-pollination. When the pistil fails to develop properly, pollination cannot lead to fertilization, resulting in reproductive failure and fruit abortion. Studies have also shown that hermaphroditic or bisexual flowers tend to exhibit higher rates of fruit abortion compared to unisexual flowers, possibly due to resource allocation conflicts or selective fertilization pressures. ^{[4] [5]}

Illustrative examples include species affected by Trichilogaster acaciaelongifoliae , a gall-forming wasp that causes extensive floral abortion in invasive Australian wattles.

Galls of Trichilogaster acaciaelongifoliae

Causes of fruit & flower abortion

Flower abortion may occur due to one or more of the following causes:

• Resource limitations: When resources like water, nitrogen, or phosphorus are limited, plants may abort flowers or young fruits to conserve energy for survival or to support fewer but more viable offspring. ^{[6] [7]}
• Pollination failure: Flowers that fail to receive adequate or compatible pollen often abort prior to fruit set. ^[1]
• Genetic or hormonal regulation: Some species naturally produce excess flowers, only a subset of which develop into fruits. Hormones such as auxins and cytokinins play key roles in this selective abortion. ^[8]
• Environmental stress: Extreme heat, drought, or other abiotic stressors can induce flower or fruit abortion. ^[9]
• Pest and pathogen activity: Certain insects and pathogens can disrupt flower developments, either directly (through damage) or indirectly (by manipulating plant hormones). ^[10]
• Sexual expression: In dioecious or subdioecious plants, individuals may bear non-functional or abortive flowers of the opposite sex or hermaphroditic flowers with aborted pistils. ^[11]

Notable examples of abortion in plants

Several plant species or associated organisms exhibit noteworthy patterns of flower or fruit abortion:

• Aucuba japonica (Japanese laurel): Commonly displays male flowers with fully developed stamens and abortive female parts. Many cultivated varieties are male and require a female plant for berry production. ^[12]
• Urginea nagarjunae: A rare species in India, it exhibits flower abortion patterns likely tied to ecological stress or reproductive strategy. ^[13]
• Trichilogaster acaciaelongifoliae : This wasp parasitizes Acacia longifolia flowers, inducing galls that cause complete abortion of reproductive structures, aiding in biological control of this invasive species. ^[14]
• Subdioecy in plants: Many species like Silene acaulis and Hebe subalpina exhibit intermediate sexual systems where abortive floral organs play a role in sex expression and evolution. ^[15]

See also

• Flower
• Stamen
• Pistil
• Plant reproductive morphology

References

1. Bawa, K. S.; Webb, C. J. (1984). "Flower, Fruit and Seed Abortion in Tropical Forest Trees: Implications for the Evolution of Paternal and Maternal Reproductive Patterns" . American Journal of Botany. 71 (5): 736–751. doi:10.2307/2443371. ISSN   0002-9122. JSTOR   2443371.
2. Smith, Arma Anna (1896). "Abortive Flower Buds of Trillium". Botanical Gazette. 22 (5): 402–403. doi:10.1086/327429.
3. "Websters Dictionary 1828 - Webster's Dictionary 1828 - Abortive". Websters Dictionary 1828. Retrieved 2025-06-04.
4. Burd, Martin (1998). ""Excess" Flower Production and Selective Fruit Abortion: A Model of Potential Benefits" . Ecology. 79 (6): 2123–2132. doi:10.2307/176715. ISSN   0012-9658. JSTOR   176715.
5. Sutherland, Steve (1987). "Why Hermaphroditic Plants Produce Many More Flowers Than Fruits: Experimental Tests with Agave mckelveyana" . Evolution. 41 (4): 750–759. doi:10.2307/2408885. ISSN   0014-3820. JSTOR   2408885.
6. Stephenson, A. G. (1981-11-01). "Flower and Fruit Abortion: Proximate Causes and Ultimate Functions" . Annual Review of Ecology, Evolution, and Systematics. 12 (1): 253–279. Bibcode:1981AnRES..12..253S. doi:10.1146/annurev.es.12.110181.001345. ISSN   1543-592X.
7. Obeso, José Ramón (2002). "The costs of reproduction in plants" . New Phytologist. 155 (3): 321–348. Bibcode:2002NewPh.155..321O. doi:10.1046/j.1469-8137.2002.00477.x. ISSN   1469-8137. PMID   33873312.
8. Yasuhiro, I.; Toshitsugu, N. (2015-06-11). "Development and regulation of pedicel abscission in tomato". Frontiers in Plant Science. 6 (442): 442. Bibcode:2015FrPS....6..442I. doi: 10.3389/fpls.2015.00442 . ISSN   1664-462X. PMC   4462994 . PMID   26124769.
9. Zinn, K. E.; Tunc-Ozdemir, M.; Harper, J. F. (2010-03-29). "Temperature stress and plant sexual reproduction: uncovering the weakest links". Journal of Experimental Botany. 61 (7): 1959–1968. doi:10.1093/jxb/erq103. PMC   2882263 . PMID   20421194.
10. Van Klinken, Rieks Dekker; Edwards, Owain Rhys (2002). "Is host-specificity of weed biological control agents likely to evolve rapidly following establishment?" . Ecology Letters. 5 (4): 590–596. Bibcode:2002EcolL...5..590V. doi:10.1046/j.1461-0248.2002.00343.x. ISSN   1461-0248.
11. Delph, Lynda F. (1999), Geber, Monica A.; Dawson, Todd E.; Delph, Lynda F. (eds.), "Sexual Dimorphism in Life History" , Gender and Sexual Dimorphism in Flowering Plants, Berlin, Heidelberg: Springer, pp. 149–173, doi:10.1007/978-3-662-03908-3_6, ISBN   978-3-662-03908-3 , retrieved 2025-06-04
12. Philip, C.; Lord, T. (2016). Cubey, J. (ed.). RHS Plant Finder 2016 . Internet Archive (30th ed.). London: Royal Horticultural Society. pp. 1–956. ISBN   978-1-907057-66-3.
13. Hemadri, K.; Sasibhushan, S. (October 1982). "URGINEA NAGARJUNAE HEMADRI ET SWAHARI A NEW SPECIES OF ULIACEAE FROM INDIA (A NEW PLANT DISCOVERY)" (PDF). Ancient Science of Life. 2 (2): 105–110. PMC   3336716 . PMID   22556964 . Retrieved 2025-06-04.
14. Dennill, G. B.; Donnelly, D. (1991-10-01). "Biological control of Acacia longifolia and related weed species (Fabaceae) in South Africa" . Agriculture, Ecosystems & Environment. 37 (1): 115–135. Bibcode:1991AgEE...37..115D. doi:10.1016/0167-8809(91)90142-K. ISSN   0167-8809 . Retrieved 2025-06-04.
15. Barrett, Spencer C. H. (2002-04-01). "The evolution of plant sexual diversity" . Nature Reviews Genetics. 3 (4): 274–284. doi:10.1038/nrg776. ISSN   1471-0064. PMID   11967552 . Retrieved 2025-06-04.