The evolution of competitive strategies in annual plants

Abstract

Annual plants are common in disturbed habitats. It is frequently assumed that because these habitats often have low-plant density, competition is not important in shaping the ecological strategies of annual plants. We test for competitive strategies in genotypes of the short-lived annual plant Arabidopsis thaliana. Genotypes were grown in treatments with or without conspecific competitors. We measured size at reproduction and fitness (fruit production) at final development. We estimated competitive ability in each genotype at first reproduction (the ability to maintain size in the presence of competitors) and at final development (the ability to maintain fruit production in the presence of competitors). Genotypes showed relatively high competitive ability measured as fruit production at final development, but most genotypes had low competitive ability measured as size at reproduction. Our results suggest that competition has been important in the evolution of strategies in these genotypes but vegetative size is not a strong predictor of competitive ability. Rather, competitive ability is determined by the capacity to reproduce efficiently in the presence of competitors. The competitive strategies expressed across these genotypes suggest that competition has been a selective force in these plants, and that a fast life history is not equivalent to an ''r-strategy.''

Reproductive efficiency and shade avoidance plasticity under simulated competition

“…That is, under competition, species invested more resources to reproduction and initiated reproduction at smaller sizes than for those plants growing in the absence of competition. Therefore, our results support a life‐history theory of reproduction under competition which predicts that short‐lived (annual) plants can express a competitive strategy and intense competition induces a shift to early and efficient reproduction in plants across life histories and growth forms (Bonser and Ladd ; Bonser ). Allocation of resources to survival or growth rather than reproduction can increase lifetime fitness in the long term (Sih ; Nicotra et al.…”

Costs of female reproduction in a conifer tree: a whole‐tree level assessment

“…The study of costs of reproduction in trees is more complex than in short‐lived taxa, as investment in growth, maintenance and reproduction might vary among life stages (Thomas ). In fact, investment in maintenance is a key difference between long‐ and short‐lived plants (Bonser & Ladd ), which is likely to have a deep influence on the expression of costs of reproduction (Sala et al . ).…”

“…The study of costs of reproduction in trees is more complex than in shortlived taxa, as investment in growth, maintenance and reproduction might vary among life stages (Thomas 2011). In fact, investment in maintenance is a key difference between longand short-lived plants (Bonser & Ladd 2011), which is likely to have a deep influence on the expression of costs of reproduction (Sala et al 2012). Despite more challenging, the study of costs of reproduction in trees deserves particular attention as trees are foundation species upon which forest ecosystems depend (Petit & Hampe 2006).…”

Developmental Change of Vegetative Plant Architecture of Annual-Form-Wild Rice (<i>Oryza rufipogon</i> Griff.) Elevates Competitive Ability during the Late Development under a Dense Condition

“…result of competition) like the competition studies of the other annual plant species [20,25,26], but the behaviors have been treated as a black box. AFW rice drastically changes the plant architecture from flat to elect shape during the late vegetative plant development [27].…”

“…In competition studies of higher plants, traits conferring CA was generally determined, depending on statistical analysis for the relationship between target trait(s) and the measured CA [16,17,20,21,25,[31][32][33], except for rice allelopathy studies [34,35]. On the other hand, the genetic analysis tended to be simply performed on the trait conferring CA that has been suggested by the previous phenotypic studies especially in rice [36][37][38][39][40], although the genetic materials and environments (or weed species and/or agroecotypes) differed from those used in the previous competition experiments.…”