Editing Annual plant

{{short description|Plant which completes its life cycle within one growing season and then dies}}
{{Use dmy dates|date=December 2023}}  
[[Image:Doperwt rijserwt peulen Pisum sativum.jpg|right|thumb|240px|[[Pea]]s are an annual plant.]]
An '''annual plant''' is a plant that completes its [[biological life cycle|life cycle]], from [[germination]] to the production of [[seed]]s, within one [[growing season]], and then dies. Globally, 6% of all plant species and 15% of herbaceous plants (excluding trees and shrubs) are annuals.<ref name=":0">{{Cite journal |last1=Poppenwimer |first1=Tyler |last2=Mayrose |first2=Itay |last3=DeMalach |first3=Niv |date=2023-11-08 |title=Revising the global biogeography of annual and perennial plants |journal=Nature |volume=624 |issue=7990 |language=en |pages=109–114 |doi=10.1038/s41586-023-06644-x |pmid=37938778 |pmc=10830411 |issn=1476-4687 |arxiv=2304.13101 |bibcode=2023Natur.624..109P |s2cid=260332117}}</ref> The annual life cycle has independently emerged in over 120 different plant families throughout the entire [[Flowering plant|angiosperm]] phylogeny.<ref>{{Cite journal |last=Friedman |first=Jannice |date=2020-11-02 |title=The Evolution of Annual and Perennial Plant Life Histories: Ecological Correlates and Genetic Mechanisms |url=https://www.annualreviews.org/doi/10.1146/annurev-ecolsys-110218-024638 |journal=Annual Review of Ecology, Evolution, and Systematics |language=en |volume=51 |issue=1 |pages=461–481 |doi=10.1146/annurev-ecolsys-110218-024638 |s2cid=225237602 |issn=1543-592X}}</ref>

== The evolutionary and ecological drivers of the annual life cycle ==
Traditionally, there has been a prevailing assumption that annuals have evolved from [[perennial]] ancestors. However, recent research challenges this notion, revealing instances where perennials have evolved from annual ancestors.<ref name=":2">{{Cite journal |last1=Hjertaas |first1=Ane C. |last2=Preston |first2=Jill C. |last3=Kainulainen |first3=Kent |last4=Humphreys |first4=Aelys M. |last5=Fjellheim |first5=Siri |date=2023 |title=Convergent evolution of the annual life history syndrome from perennial ancestors |journal=Frontiers in Plant Science |volume=13 |doi=10.3389/fpls.2022.1048656 |pmid=36684797 |pmc=9846227 |issn=1664-462X |doi-access=free}}</ref> Intriguingly, models propose that transition rates from an annual to a perennial life cycle are twice as fast as the reverse transition.<ref name=":1">{{Cite journal |last1=Boyko |first1=James D. |last2=Hagen |first2=Eric R. |last3=Beaulieu |first3=Jeremy M. |last4=Vasconcelos |first4=Thais |date=November 2023 |title=The evolutionary responses of life-history strategies to climatic variability in flowering plants |journal=New Phytologist |language=en |volume=240 |issue=4 |pages=1587–1600 |doi=10.1111/nph.18971 |issn=0028-646X |doi-access=free|pmid=37194450 |bibcode=2023NewPh.240.1587B }}</ref>

The [[Life history theory|life-history theory]] posits that annual plants are favored when adult mortality is higher than seedling (or seed) mortality,<ref>{{Cite journal |last1=Charnov |first1=Eric L. |last2=Schaffer |first2=William M. |date=November 1973 |title=Life-History Consequences of Natural Selection: Cole's Result Revisited |url=https://www.journals.uchicago.edu/doi/10.1086/282877 |journal=The American Naturalist |language=en |volume=107 |issue=958 |pages=791–793 |doi=10.1086/282877 |bibcode=1973ANat..107..791C |s2cid=264255777 |issn=0003-0147}}</ref> i.e., annuals will dominate environments with disturbances or high temporal variability, reducing adult survival. This hypothesis finds support in observations of increased prevalence of annuals in regions with hot-dry summers,<ref name=":0" /><ref name=":1" /><ref>{{Cite journal |last1=Taylor |first1=Amanda |last2=Weigelt |first2=Patrick |last3=Denelle |first3=Pierre |last4=Cai |first4=Lirong |last5=Kreft |first5=Holger |date=November 2023 |title=The contribution of plant life and growth forms to global gradients of vascular plant diversity |journal=New Phytologist |language=en |volume=240 |issue=4 |pages=1548–1560 |doi=10.1111/nph.19011 |pmid=37264995 |issn=0028-646X |doi-access=free|bibcode=2023NewPh.240.1548T }}</ref> with elevated adult mortality and high seed persistence. Furthermore, the evolution of the annual life cycle under hot-dry summer in different families makes it one of the best examples of [[convergent evolution]].<ref name=":0" /><ref name=":1" /><ref name=":2" /> Additionally, annual prevalence is also positively affected by year-to-year variability.<ref name=":0" />

Globally, the prevalence of annual plants shows an upward trend with an increasing human footprint.<ref name=":0" /> Moreover, domestic grazing has been identified as contributing to the heightened abundance of annuals in grasslands.<ref>{{Cite journal |last1=Díaz |first1=Sandra |last2=Lavorel |first2=Sandra |last3=McIntyre |first3=Sue |last4=Falczuk |first4=Valeria |last5=Casanoves |first5=Fernando |last6=Milchunas |first6=Daniel G. |last7=Skarpe |first7=Christina |last8=Rusch |first8=Graciela |last9=Sternberg |first9=Marcelo |last10=Noy-Meir |first10=Imanuel |last11=Landsberg |first11=Jill |last12=Zhang |first12=Wei |last13=Clark |first13=Harry |last14=Campbell |first14=Bruce D. |date=February 2007 |title=Plant trait responses to grazing – a global synthesis |url=https://onlinelibrary.wiley.com/doi/10.1111/j.1365-2486.2006.01288.x |journal=Global Change Biology |language=en |volume=13 |issue=2 |pages=313–341 |doi=10.1111/j.1365-2486.2006.01288.x |bibcode=2007GCBio..13..313D |hdl=11336/42236 |s2cid=84886127 |issn=1354-1013 |hdl-access=free}}</ref> Disturbances linked to activities like grazing and agriculture, particularly following European settlement, have facilitated the invasion of annual species from Europe and Asia into the New World.

In various ecosystems, the dominance of annual plants is often a temporary phase during secondary [[Ecological succession|succession]], particularly in the aftermath of disturbances. For instance, after fields are abandoned, annuals may initially colonize them but are eventually replaced by long-lived species.<ref>{{Cite journal |last1=Clark |first1=Adam Thomas |last2=Knops |first2=Johannes M. H. |last3=Tilman |first3=Dave |date=March 2019 |editor-last=Bardgett |editor-first=Richard |title=Contingent factors explain average divergence in functional composition over 88 years of old field succession |url=https://besjournals.onlinelibrary.wiley.com/doi/10.1111/1365-2745.13070 |journal=Journal of Ecology |language=en |volume=107 |issue=2 |pages=545–558 |doi=10.1111/1365-2745.13070 |bibcode=2019JEcol.107..545C |issn=0022-0477}}</ref> However, in certain Mediterranean systems, a unique scenario unfolds: when annuals establish dominance, perennials do not necessarily supplant them.<ref>{{Cite journal |last1=Uricchio |first1=Lawrence H. |last2=Daws |first2=S. Caroline |last3=Spear |first3=Erin R. |last4=Mordecai |first4=Erin A. |date=February 2019 |title=Priority Effects and Nonhierarchical Competition Shape Species Composition in a Complex Grassland Community |journal=The American Naturalist |language=en |volume=193 |issue=2 |pages=213–226 |doi=10.1086/701434 |issn=0003-0147 |pmc=8518031 |pmid=30720356|bibcode=2019ANat..193..213U }}</ref> This peculiarity is attributed to [[alternative stable state]]s in the system—both annual dominance and perennial states prove stable, with the ultimate system state dependent on the initial conditions.<ref>{{Cite journal |last1=DeMalach |first1=Niv |last2=Shnerb |first2=Nadav |last3=Fukami |first3=Tadashi |date=2021-08-01 |title=Alternative States in Plant Communities Driven by a Life-History Trade-Off and Demographic Stochasticity |url=https://www.journals.uchicago.edu/doi/10.1086/714418 |journal=The American Naturalist |language=en |volume=198 |issue=2 |pages=E27–E36 |doi=10.1086/714418 |pmid=34260874 |arxiv=1812.03971 |bibcode=2021ANat..198E..27D |s2cid=226191832 |issn=0003-0147}}</ref>

== Traits of annuals and their implication for agriculture ==
Annual plants commonly exhibit a higher growth rate, allocate more resources to seeds, and allocate fewer resources to roots than perennials.<ref>{{Cite journal |last1=Vico |first1=Giulia |last2=Manzoni |first2=Stefano |last3=Nkurunziza |first3=Libère |last4=Murphy |first4=Kevin |last5=Weih |first5=Martin |date=January 2016 |title=Trade-offs between seed output and life span – a quantitative comparison of traits between annual and perennial congeneric species |url=https://nph.onlinelibrary.wiley.com/doi/10.1111/nph.13574 |journal=New Phytologist |language=en |volume=209 |issue=1 |pages=104–114 |doi=10.1111/nph.13574 |pmid=26214792 |bibcode=2016NewPh.209..104V |issn=0028-646X}}</ref> In contrast to perennials, which feature long-lived plants and short-lived seeds, annual plants compensate for their lower longevity by maintaining a higher persistence of [[Soil seed bank|soil seed banks]].<ref>{{Cite journal |last1=DeMalach |first1=Niv |last2=Kigel |first2=Jaime |last3=Sternberg |first3=Marcelo |date=2023-03-01 |title=Contrasting dynamics of seed banks and standing vegetation of annuals and perennials along a rainfall gradient |url=https://www.sciencedirect.com/science/article/pii/S1433831923000021 |journal=Perspectives in Plant Ecology, Evolution and Systematics |volume=58 |pages=125718 |doi=10.1016/j.ppees.2023.125718 |arxiv=2301.12696 |bibcode=2023PPEES..5825718D |s2cid=256389403 |issn=1433-8319}}</ref> These differences in life history strategies profoundly affect ecosystem functioning and services. For instance, annuals, by allocating less resources belowground, play a more minor role in reducing erosion, storing organic carbon, and achieving lower nutrient- and water-use efficiencies than perennials.<ref>{{Cite journal |last1=Glover |first1=Jerry D. |last2=Reganold |first2=John P. |last3=Cox |first3=Cindy M. |date=September 2012 |title=Plant perennials to save Africa's soils |url=https://www.nature.com/articles/489359a |journal=Nature |language=en |volume=489 |issue=7416 |pages=359–361 |doi=10.1038/489359a |pmid=22996532 |issn=1476-4687}}</ref>

The distinctions between annual and perennial plants are notably evident in agricultural contexts. Despite constituting a minor part of global biomass, annual species stand out as the primary food source for humankind, likely owing to their greater allocation of resources to seed production, thereby enhancing agricultural productivity. In the Anthropocene epoch, marked by human impact on the environment, there has been a substantial increase in the global cover of annuals.<ref>{{Cite journal |last1=Foley |first1=Jonathan A. |last2=DeFries |first2=Ruth |last3=Asner |first3=Gregory P. |last4=Barford |first4=Carol |last5=Bonan |first5=Gordon |last6=Carpenter |first6=Stephen R. |last7=Chapin |first7=F. Stuart |last8=Coe |first8=Michael T. |last9=Daily |first9=Gretchen C. |last10=Gibbs |first10=Holly K. |last11=Helkowski |first11=Joseph H. |last12=Holloway |first12=Tracey |last13=Howard |first13=Erica A. |last14=Kucharik |first14=Christopher J. |last15=Monfreda |first15=Chad |date=2005-07-22 |title=Global Consequences of Land Use |url=https://www.science.org/doi/10.1126/science.1111772 |journal=Science |language=en |volume=309 |issue=5734 |pages=570–574 |doi=10.1126/science.1111772 |pmid=16040698 |bibcode=2005Sci...309..570F |s2cid=5711915 |issn=0036-8075}}</ref> This shift is primarily attributed to the conversion of natural systems, often dominated by perennials, into annual cropland. Currently, annual plants cover approximately 70% of croplands and contribute to around 80% of worldwide food consumption.<ref>{{Cite journal |last1=Pimentel |first1=David |last2=Cerasale |first2=David |last3=Stanley |first3=Rose C. |last4=Perlman |first4=Rachel |last5=Newman |first5=Elise M. |last6=Brent |first6=Lincoln C. |last7=Mullan |first7=Amanda |last8=Chang |first8=Debbie Tai-I |date=2012-10-15 |title=Annual vs. perennial grain production |url=https://www.sciencedirect.com/science/article/pii/S0167880912002058 |journal=Agriculture, Ecosystems & Environment |volume=161 |pages=1–9 |doi=10.1016/j.agee.2012.05.025 |bibcode=2012AgEE..161....1P |issn=0167-8809}}</ref>

==Molecular genetics==
In 2008, it was discovered that the inactivation of only two genes in one species of annual plant leads to its conversion into a [[perennial plant]].<ref>{{cite journal |pmid=18997783 |year=2008 |last1=Melzer |first1=S |last2=Lens |first2=F |last3=Gennen |first3=J |last4=Vanneste |first4=S |last5=Rohde |first5=A |last6=Beeckman |first6=T |title=Flowering-time genes modulate meristem determinacy and growth form in Arabidopsis thaliana |volume=40 |issue=12 |pages=1489–92 |doi=10.1038/ng.253 |journal=Nature Genetics |s2cid=13225884 |url=http://www.repository.naturalis.nl/document/456722}}</ref> Researchers deactivated the SOC1 and FUL genes (which control flowering time) of ''[[Arabidopsis thaliana]]''. This switch established [[phenotypes]] common in perennial plants, such as [[wood]] formation.

==See also==
*{{annotated link|Biennial plant}}
*{{annotated link|Perennial plant}}
*{{annotated link|Monocarpic plant}} - Plant that flowers & sets seeds once, then dies.
*[[Ephemeral plant]]

==References==
{{reflist}}

==External links==
{{Commons category|position=left|Annuals}}

{{Authority control}}

[[Category:Annual plants| ]]