Editing Flowering plant (section)

===Adaptive function of flowers===

Charles Darwin in his 1878 book The Effects of Cross and Self-Fertilization in the Vegetable Kingdom<ref>{{cite book |last=Darwin |first=Charles R. |author-link=Charles Darwin |year=1878 |title=The effects of cross and self fertilisation in the vegetable kingdom |location=London |publisher=John Murray |url=https://darwin-online.org.uk/converted/pdf/1878_Fertilisation_F1251.pdf}}</ref> in the initial paragraph of chapter XII noted "The first and most important of the conclusions which may be drawn from the observations given in this volume, is that generally cross-fertilisation is beneficial and self-fertilisation often injurious, at least with the plants on which I experimented." [[Flower]]s emerged in plant evolution as an adaptation for the promotion of cross-[[fertilisation]] ([[outcrossing]]), a process that allows the masking of deleterious [[mutation]]s in the [[genome]] of progeny. The masking effect is known as [[complementation (genetics)|genetic complementation]].<ref name="Bernstein 1985">{{cite journal |last1=Bernstein |first1=Harris |last2=Byerly |first2=Henry C. |last3=Hopf |first3=Frederic A. |last4=Michod |first4=Richard E. |title=Genetic Damage, Mutation, and the Evolution of Sex |journal=Science |volume=229 |issue=4719 |date=20 September 1985 |doi=10.1126/science.3898363 |pages=1277–1281|pmid=3898363 |bibcode=1985Sci...229.1277B }}</ref> [[Meiosis]] in flowering plants provides a direct mechanism for [[DNA repair|repairing DNA]] through genetic recombination in reproductive tissues.<ref name="Hörandl 2024">{{cite journal |last=Hörandl |first=Elvira |title=Apomixis and the paradox of sex in plants |journal=Annals of Botany |volume=134 |issue=1 |date=7 June 2024 |pmid=38497809 |pmc=11161571 |doi=10.1093/aob/mcae044 |doi-access=free |pages=1–18 |url=https://academic.oup.com/aob/advance-article-pdf/doi/10.1093/aob/mcae044/57132588/mcae044.pdf |access-date=17 January 2025}}</ref> [[Sexual reproduction]] appears to be required for maintaining long-term [[genome|genomic]] integrity and only infrequent combinations of extrinsic and intrinsic factors permit shifts to asexuality.<ref name="Hörandl 2024"/> Thus the two fundamental aspects of sexual reproduction in flowering plants, cross-fertilization (outcrossing) and meiosis appear to be maintained respectively by the advantages of genetic complementation and recombinational repair.<ref name="Bernstein 1985"/>