Annual vs. perennial plant evolution

Perennial Silphium integrifolium species (Asteraceae), which is being bred for edible seeds.

Annuality (living and reproducing in a single year) and perenniality (living more than two years) represent major life history strategies within plant lineages.[1] These traits can shift from one to another over both macroevolutionary and microevolutionary timescales.[2] While perenniality and annuality are often described as discrete either-or traits, they often occur in a continuous spectrum.[2] The complex history of switches between annual and perennial habit involve both natural and artificial causes, and studies of this fluctuation have importance to sustainable agriculture. (Note that "perennial" here refers to both woody and herbaceous perennial species.)

Globally, only 6% of all plant species and 15% of herbaceous plants (excluding trees and shrubs) are annuals.[3] The annual life cycle has independently emerged in over 120 different plant families throughout the entire angiosperm phylogeny.[4] The life-history theory posits that annual plants are favored when adult mortality is higher than seedling (or seed) mortality,[5] 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,[3] 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. Additionally, annual prevalence is also positively affected by year-to-year variability.[3]

According to some studies, either the trait of annuality or perenniality may be ancestral.[6][7] This contradicts the commonly held belief that annuality is a derived trait from an ancestral perennial life form, as is suggested by a regarded plant population biology text.[8]

  1. ^ Miller, Allison J.; Gross, Briana L. (2011-09-01). "From forest to field: Perennial fruit crop domestication". American Journal of Botany. 98 (9): 1389–1414. doi:10.3732/ajb.1000522. ISSN 0002-9122. PMID 21865506.
  2. ^ a b Fox, Gordon A. (1990-06-01). "Perennation and the Persistence of Annual Life Histories". The American Naturalist. 135 (6): 829–840. doi:10.1086/285076. ISSN 0003-0147. S2CID 85114329.
  3. ^ a b c Poppenwimer, Tyler; Mayrose, Itay; DeMalach, Niv (2023-12-07). "Revising the global biogeography of annual and perennial plants". Nature. 624 (7990): 109–114. arXiv:2304.13101. doi:10.1038/s41586-023-06644-x. ISSN 0028-0836.
  4. ^ Friedman, Jannice (2020-11-02). "The Evolution of Annual and Perennial Plant Life Histories: Ecological Correlates and Genetic Mechanisms". Annual Review of Ecology, Evolution, and Systematics. 51 (1): 461–481. doi:10.1146/annurev-ecolsys-110218-024638. ISSN 1543-592X.
  5. ^ Charnov, Eric L.; Schaffer, William M. (November 1973). "Life-History Consequences of Natural Selection: Cole's Result Revisited". The American Naturalist. 107 (958): 791–793. doi:10.1086/282877. ISSN 0003-0147.
  6. ^ Tank, David C.; Olmstead, Richard G. (2008-05-01). "From annuals to perennials: phylogeny of subtribe Castillejinae (Orobanchaceae)". American Journal of Botany. 95 (5): 608–625. doi:10.3732/ajb.2007346. ISSN 0002-9122. PMID 21632387.
  7. ^ Cite error: The named reference :10 was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference :19 was invoked but never defined (see the help page).