Editing Self-incompatibility (section)

===Late-acting self-incompatibility (LSI)===
'''Late-acting self-incompatibility (LSI)''' is also termed '''[[ovary|ovarian]] self-incompatibility (OSI)'''. In this mechanism, self pollen germinates and reaches the ovules, but no [[fruit]] is set.<ref name="seavey">{{cite journal |doi=10.1007/BF02861001 | vauthors = Seavey SF, Bawa KS | title=Late-acting self-incompatibility in angiosperms |journal=Botanical Review |volume=52 |pages=195–218 |year=1986 |issue=2 | bibcode = 1986BotRv..52..195S |s2cid=34443387 }}</ref><ref>{{cite book | vauthors = Sage TL, Bertin RI, Williams EG | chapter = Ovarian and other late-acting self-incompatibility systems | veditors = Williams EG, Knox RB, Clarke AE | title = Genetic control of self-incompatibility and reproductive development in flowering plants | series = Advances in Cellular and Molecular Biology of Plants | date = 1994 | volume = 2 | pages = 116–140 | doi = 10.1007/978-94-017-1669-7_7 | publisher = Kluwer Academic | location = Amsterdam | isbn = 978-90-481-4340-5 }}</ref> LSI can be pre-[[zygote|zygotic]] (e.g. deterioration of the [[embryo sac]] prior to pollen tube entry, as in ''[[Narcissus triandrus]]''<ref>{{cite journal | vauthors = Sage TL, Strumas F, Cole WW, Barrett SC | title = Differential ovule development following self- and cross-pollination: the basis of self-sterility in Narcissus triandrus (Amaryllidaceae) | journal = American Journal of Botany | volume = 86 | issue = 6 | pages = 855–870 | date = June 1999 | pmid = 10371727 | doi = 10.2307/2656706 | s2cid = 25585101 | doi-access = free | jstor = 2656706 }}</ref>) or post-zygotic (malformation of the [[zygote]] or [[embryo]], as in certain species of ''[[Asclepias]]'' and in ''[[Spathodea campanulata]]''<ref>{{cite journal | vauthors = Sage TL, Williams EG |title=Self-incompatibility in Asclepias |journal=Plant Cell Incomp. Newsl. |volume=23 |pages=55–57 |year=1991 }}</ref><ref>{{cite journal | vauthors = Sparrow FK, Pearson NL |title=Pollen compatibility in ''Asclepias syriaca'' |journal=J. Agric. Res. |volume=77 |pages=187–199 |year=1948 }}</ref><ref name="lipow">{{cite journal | vauthors = Lipow SR, Wyatt R | title = Single gene control of postzygotic self-incompatibility in poke milkweed, Asclepias exaltata L | journal = Genetics | volume = 154 | issue = 2 | pages = 893–907 | date = February 2000 | pmid = 10655239 | pmc = 1460952 | doi = 10.1093/genetics/154.2.893 | name-list-style = amp }}</ref><ref>{{cite journal | vauthors = Bittencourt NS, Gibbs PE, Semir J | title = Histological study of post-pollination events in Spathodea campanulata beauv. (Bignoniaceae), a species with late-acting self-incompatibility | journal = Annals of Botany | volume = 91 | issue = 7 | pages = 827–834 | date = June 2003 | pmid = 12730069 | pmc = 4242391 | doi = 10.1093/aob/mcg088 }}</ref>).

The existence of the LSI mechanism among different taxa and in general, is subject for scientific debate. Criticizers claim, that absence of fruit set is due to genetic defects (homozygosity for lethal recessive alleles), which are the direct result of self-fertilization  ([[inbreeding depression]]).<ref>{{cite book | vauthors = Klekowski EJ | date = 1988 | title = Mutation, Developmental Selection, and Plant Evolution. | publisher = Columbia University Press | location = New York }}</ref><ref>{{cite journal |doi=10.2307/2444892 | vauthors = Waser NM, Price MV |title=Reproductive costs of self-pollination in ''Ipomopsis aggregata'' (Polemoniaceae): are ovules usurped? |jstor=2444892 |journal=American Journal of Botany |volume=78 |issue=8 |pages=1036–43 |year=1991 }}</ref><ref>{{cite book | vauthors = Lughadha N | veditors = Owen SJ, Rudall PJ | chapter = Preferential outcrossing in Gomidesia (Myrtaceae) is maintained by a post-zygotic mechanism. | title = Reproductive biology in systematics, conservation and economic botany | location = London | publisher = Royal Botanic Gardens, Kew | date = 1998 | pages = 363–379 | doi = 10.13140/RG.2.1.2787.0247 }}</ref> Supporters, on the other hand, argue for the existence of several basic criteria, which differentiate certain cases of LSI from the inbreeding depression phenomenon.<ref name="seavey"/><ref name="lipow"/>