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Wang H, Zhang ZQ, Zhang B, Wang LP, Guo W, Fang Y, Li QJ. Architectural effects regulate resource allocation within the inflorescences with nonlinear blooming patterns. AMERICAN JOURNAL OF BOTANY 2022; 109:1191-1202. [PMID: 35588305 DOI: 10.1002/ajb2.16001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 05/04/2022] [Accepted: 05/04/2022] [Indexed: 06/15/2023]
Abstract
PREMISE Spatial and temporal resource allocations within inflorescences have been well-studied in many plants based on flowering sequence or floral position. However, there had been few attempts to investigate architectural effects and resource competition in species where the blooming pattern does not follow a linear positional pattern within the inflorescence. Moreover, most flowering plants show female-biased sex allocation in early or basal flowers, but it is unclear in species with inherent and changeless ovule production. METHODS We investigated intra-inflorescence variation in reproductive traits of Salvia przewalskii, a perennial herb with 4-ouvle ovary flowers and flowering sequence-floral position decoupled inflorescences. To detect the effects of resource competition and architectural effects on reproductive success, we manipulated inflorescence (removed floral buds by position and flowering sequence) and pollination (opened and supplemented pollination). RESULTS Pollen production and dry mass deceased from bottom to top flowers but did not significantly differ following flowering sequence, resulting in male-biased sex allocation in basal flowers. The seed production, fruit set, and bud development exhibited significant declining trends from proximal to distal positions regardless of the thinning and pollen treatments. Meanwhile, the seed production, fruit set, and bud development success did not significant differ when thinning was conducted according to flowering sequence. CONCLUSIONS Architectural effects plays a crucial role in resource allocation within decoupled flowering inflorescences. Moreover, our results highlighted that inherent floral traits such as changeless ovule production, may modify architectural effects on sex allocation.
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Affiliation(s)
- Hao Wang
- Yunnan Key Laboratory of Plant Reproductive Adaptation and Evolutionary Ecology, and State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Institute of Biodiversity, School of Ecology and Environmental Science, Yunnan University, Kunming, 650504, Yunnan, China
| | - Zhi-Qiang Zhang
- Yunnan Key Laboratory of Plant Reproductive Adaptation and Evolutionary Ecology, and State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Institute of Biodiversity, School of Ecology and Environmental Science, Yunnan University, Kunming, 650504, Yunnan, China
| | - Bo Zhang
- Key Laboratory of Grassland Ecosystem of Ministry of Education, and Sino-U.S. Centers for Grazingland Ecosystem Sustainability, College of Grassland Science, Gansu Agricultural University, Lanzhou, 730070, China
| | - Li-Ping Wang
- Yunnan Key Laboratory of Plant Reproductive Adaptation and Evolutionary Ecology, and State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Institute of Biodiversity, School of Ecology and Environmental Science, Yunnan University, Kunming, 650504, Yunnan, China
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China
| | - Wen Guo
- Yunnan Key Laboratory of Plant Reproductive Adaptation and Evolutionary Ecology, and State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Institute of Biodiversity, School of Ecology and Environmental Science, Yunnan University, Kunming, 650504, Yunnan, China
| | - Ye Fang
- Shangri-La Alpine Botanical Garden, Diqing, 674400, China
| | - Qing-Jun Li
- Yunnan Key Laboratory of Plant Reproductive Adaptation and Evolutionary Ecology, and State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Institute of Biodiversity, School of Ecology and Environmental Science, Yunnan University, Kunming, 650504, Yunnan, China
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Narbona E, Jaca J, Del Valle JC, Valladares F, Buide ML. Whole-plant reddening in Silene germana is due to anthocyanin accumulation in response to visible light. PLANT BIOLOGY (STUTTGART, GERMANY) 2018; 20:968-977. [PMID: 30003657 DOI: 10.1111/plb.12875] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 07/11/2018] [Indexed: 05/20/2023]
Abstract
The phenology of anthocyanin accumulation in leaves has been widely studied in perennial plants; several hypotheses have been proposed to explain their adaptive significance. Here, we explored the photoprotection hypothesis in Silene germana, a Mediterranean annual plant with late-spring/summer flowering. We analysed the temporal patterns of anthocyanin accumulation in photosynthetic calyces, leaves and stems and throughout the reproductive season, and their relationship with flower abortion, florivory and plant mortality due to drought. In addition, the flavonoid production and the photoinhibitory response were measured in a shading experiment. The whole plant becomes red at the end of the flowering and remains red until fruiting and senescence. Calyces were redder on the side with more sun exposition. Aborted flowers showed redder calyces than those of fruiting flowers. No effect of plant redness on florivory or plant mortality was found. The shading experiment showed a positive relationship between anthocyanin accumulation and intensity of solar radiation, but plants growing in absence of UV showed similar redness than full sunlight plants. Plants growing in natural shade lack anthocyanins but produced the same amount of non-anthocyanin flavonoids. Anthocyanic and non-anthocyanic plants showed similar photochemical efficiency (Fv /Fm ) after sun exposition, but in early morning, the former showed lower Fv /Fm values. Plants growing in full sunlight produced more fruits than those of natural shade plants. Whole-plant reddening during fruiting and senescence appears to be a property of S. germana. Our results suggest that anthocyanin accumulation depends on sunlight intensity, but non-anthocyanin flavonoids are produced constitutively.
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Affiliation(s)
- E Narbona
- Department of Molecular Biology and Biochemical Engineering, Pablo de Olavide University, Sevilla, Spain
| | - J Jaca
- Mediterranean Institute for Advanced Studies (CSIC-UIB) Mallorca, Balearic Islands, Spain
| | - J C Del Valle
- Department of Molecular Biology and Biochemical Engineering, Pablo de Olavide University, Sevilla, Spain
| | - F Valladares
- Centro de Ciencias Medioambientales, Instituto de Recursos Naturales, CSIC, Madrid, Spain
| | - M L Buide
- Department of Molecular Biology and Biochemical Engineering, Pablo de Olavide University, Sevilla, Spain
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3
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Dai C, Luo WJ, Gong YB, Liu F, Wang ZX. Resource reallocation patterns within Sagittaria trifolia inflorescences following differential pollination. AMERICAN JOURNAL OF BOTANY 2018; 105:803-811. [PMID: 29710426 DOI: 10.1002/ajb2.1053] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Accepted: 01/29/2018] [Indexed: 06/08/2023]
Abstract
PREMISE OF THE STUDY Understanding resource allocation to reproduction, a key factor in life history tradeoffs, has long intrigued plant ecologists. Despite the recognized importance of understanding the movement of resources among flowers following variable pollination, the patterns of resource reallocation to plant reproductive organs have not been thoroughly addressed. In this study, we aimed to empirically explore how resources redistribute within inflorescences in response to differential pollination intensities. METHODS Using a common herb, Sagittaria trifolia, we conducted supplemental and controlled pollination for single, some, or all flowers in simple and complex inflorescences, and compared their resulting fruiting probabilities, seed production, and average seed masses. KEY RESULTS Pollen supplementation of a single flower significantly increased its fruiting probability; however, the same manipulation of an inflorescence did not increase its overall reproduction. Single pollen-supplemented flowers had a higher percentage fruit set than inflorescences receiving supplemental pollination. In complex inflorescences, supplemental pollination had no effect on the reproductive success of flowers on the lateral or main branches. CONCLUSIONS We provided evidence of resource reallocation from controlled to pollen-supplemented flowers in simple inflorescences; however, resources were unlikely to be reallocated between the main and lateral branches in the complex inflorescences, suggesting that flowering branches represent integrated physiological units in S. trifolia. The results also demonstrated that single-flower supplemental pollination would exaggerate pollen limitation and lead to a biased understanding of a plant's reproductive status.
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Affiliation(s)
- Can Dai
- School of Resources and Environmental Science, Hubei University, Wuhan, 430062, China
- Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Wuhan, 430062, China
- Hubei Key Laboratory of Regional Development and Environmental Response (Hubei University), Wuhan, 430062, China
| | - Wen-Jie Luo
- School of Resources and Environmental Science, Hubei University, Wuhan, 430062, China
| | - Yan-Bing Gong
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Fan Liu
- Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, 430074, China
| | - Zheng-Xiang Wang
- School of Resources and Environmental Science, Hubei University, Wuhan, 430062, China
- Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Wuhan, 430062, China
- Hubei Key Laboratory of Regional Development and Environmental Response (Hubei University), Wuhan, 430062, China
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Forrest JRK. Plant Size, Sexual Selection, and the Evolution of Protandry in Dioecious Plants. Am Nat 2014; 184:338-51. [DOI: 10.1086/677295] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Zalucki JM, King R, Hughes JM. Outcrossing rates and reproductive success inXanthorrhoea johnsonii(Xanthorrhoeaceae), in south east Queensland, Australia. Biol J Linn Soc Lond 2013. [DOI: 10.1111/bij.12135] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Jacinta M. Zalucki
- Environmental Futures Centre; Griffith University; Nathan; QLD; 4111; Australia
| | - Rachel King
- Department of Mathematics and Computing; Faculty of Sciences; University of Southern Queensland; Toowoomba; QLD; 4350; Australia
| | - Jane M. Hughes
- Australian Rivers Institute; Griffith University; Nathan; QLD; 4111; Australia
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Ida TY, Harder LD, Kudo G. Demand-driven resource investment in annual seed production by a perennial angiosperm precludes resource limitation. Ecology 2013; 94:51-61. [DOI: 10.1890/12-0619.1] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Leslie AB. Branching habit and the allocation of reproductive resources in conifers. ANNALS OF BOTANY 2012; 110:915-921. [PMID: 22782240 PMCID: PMC3423808 DOI: 10.1093/aob/mcs150] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Accepted: 05/15/2012] [Indexed: 06/01/2023]
Abstract
BACKGROUND AND AIMS Correlated relationships between branch thickness, branch density, and twig and leaf size have been used extensively to study the evolution of plant canopy architecture, but fewer studies have explored the impact of these relationships on the allocation of reproductive resources. This study quantifies pollen cone production in conifers, which have similar basic reproductive biology but vary dramatically in branching habit, in order to test how differences in branch diameter influence pollen cone size and the density with which they are deployed in the canopy. METHODS Measurements of canopy branch density, the number of cones per branch and cone size were used to estimate the amount of pollen cone tissues produced by 16 species in three major conifer clades. The number of pollen grains produced was also estimated using direct counts from individual pollen cones. KEY RESULTS The total amount of pollen cone tissues in the conifer canopy varied little among species and clades, although vegetative traits such as branch thickness, branch density and pollen cone size varied over several orders of magnitude. However, branching habit controls the way these tissues are deployed: taxa with small branches produce small pollen cones at a high density, while taxa with large branches produce large cones relatively sparsely. CONCLUSIONS Conifers appear to invest similar amounts of energy in pollen production independent of branching habit. However, similar associations between branch thickness, branch density and pollen cone size are seen across conifers, including members of living and extinct groups not directly studied here. This suggests that reproductive features relating to pollen cone size are in large part a function of the evolution of vegetative morphology and branching habit.
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Affiliation(s)
- Andrew B Leslie
- School of Forestry and Environmental Studies, Yale University, New Haven, CT 06511, USA.
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Zhang G, Xie T, Du G. Variation in floral sex allocation, female success, and seed predation within racemiform synflorescence in the gynomonoecious Ligularia virgaurea (Asteraceae). JOURNAL OF PLANT RESEARCH 2012; 125:527-538. [PMID: 22270694 DOI: 10.1007/s10265-011-0466-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2011] [Accepted: 11/02/2011] [Indexed: 05/31/2023]
Abstract
Studies of diclinous species have showed that floral sex allocation and female reproductive success were quite variable within inflorescences. However, little attention has been paid to gynomonoecious species, in which individuals produce both female and bisexual flowers. The purpose of this study was to investigate the variations in reproductive patterns at different capitulum positions within racemiform synflorescence in Ligularia virgaurea, and to determine selective mechanisms of variations in reproductive patterns. We conducted observational and experimental studies in natural populations of the gynomonoecious composite L. virgaurea. Floral sex allocation, seed production and pre-dispersal seed predation were quantified in the field. The results showed several patterns of variation from top to bottom capitula, including an increase in bisexual flowers and flower number per capitulum, but a decrease in seed set and size. Removing earlier capitula during bud stage did not change floral sex allocation in later capitula. And no effect was found on seed set under supplemental pollination. Thus, although it has been reported many times in previous studies, the variation of floral sex allocation in L. virgaurea may not result from architectural effect or mating environment, and the variation of seed production could not be fully explained by pollination success. Additionally, our results showed that L. virgaurea was susceptible to high levels of bisexual biased predation, which was greater for top capitula. We therefore suggest that these variations may help to enhance reproductive success of L. virgaurea in the face of bisexual-biased seed predation.
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Affiliation(s)
- Gefei Zhang
- MOE Key Laboratory of Arid and Grassland Ecology, Lanzhou University, Lanzhou 730000, China
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Tang JY, Ren MX. Sex allocation and functional bias of quaternary and quinary flowers on same inflorescence in the hermaphrodite Ruta graveolens. ACTA OECOLOGICA-INTERNATIONAL JOURNAL OF ECOLOGY 2011. [DOI: 10.1016/j.actao.2011.05.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Cao G, Xue L, Li Y, Pan K. The relative importance of architecture and resource competition in allocation to pollen and ovule number within inflorescences of Hosta ventricosa varies with the resource pools. ANNALS OF BOTANY 2011; 107:1413-9. [PMID: 21486925 PMCID: PMC3101151 DOI: 10.1093/aob/mcr085] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2010] [Revised: 02/10/2011] [Accepted: 02/25/2011] [Indexed: 05/30/2023]
Abstract
BACKGROUND AND AIMS Allocation of resources to floral traits often declines distally within inflorescences in flowering plants. Architecture and resource competition have been proposed as underlying mechanisms. The aim of the present study is to assess the relative importance of resource competition and architectural effects in pollen and ovule production on racemes of Hosta ventricosa, an apomictic perennial herb. METHODS Combinations of two defoliation treatments (intact and defoliated) and two fruit-set treatments (no-fruit and fruit) were created, and the roles of architecture and resource competition at each resource level were assessed. KEY RESULTS Pollen and ovule number per flower increased after defoliation, but pollen to ovule ratio per flower did not change. Pollen, ovules and the pollen to ovule ratio per flower declined distally on racemes at each resource level. In the intact treatment, fruit development of early flowers did not affect either pollen or ovule number of late flowers. In the defoliated treatment, fruit development of early flowers reduced both pollen and ovule numbers of late flowers due to over-compensation caused by defoliation. Late flowers on defoliated fruit racemes produced less pollen than intact fruit racemes but the same number of ovules; therefore, the reduction in pollen number was not caused by over-compensation. In addition, the fruit-set rate of early flowers during flowering was higher in intact racemes than in defoliated racemes. CONCLUSIONS In flowering plants, the relative importance of architecture and resource competition in allocation to pollen and ovules may vary with the resource pools or the overall resource availability of maternal plants.
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Affiliation(s)
- Guoxing Cao
- Sichuan Provincial Key Laboratory of Ecological Forestry Engineering, Sichuan Agricultural University, Yaan, China.
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11
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Brookes RH, Jesson LK, Burd M. Reproductive investment within inflorescences of Stylidium armeria varies with the strength of early resource commitment. ANNALS OF BOTANY 2010; 105:697-705. [PMID: 20375201 PMCID: PMC2859907 DOI: 10.1093/aob/mcq026] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2009] [Revised: 08/18/2009] [Accepted: 01/07/2010] [Indexed: 05/29/2023]
Abstract
BACKGROUND AND AIMS Resource allocation to flowers, fruits and seeds can vary greatly within an inflorescence. For example, distal fruits are often smaller and produce fewer and smaller fruits and seeds than more basal fruits. To assess the causes and functional significance of intra-inflorescence variation, pollen and resources were manipulated to test whether such patterns could be altered within racemes of Stylidum armeria, a perennial Australian herb. METHODS Pollen and resource levels were manipulated over two flowering seasons. How the number of ovules, fertilized ovules and seeds, the probability of fruit set, and the biomass of floral and fruiting structures varied with their position on the raceme were analysed. KEY RESULTS Most plants showed a decline in ovule and seed number toward the distal positions on the raceme, but plants differed in their pattern of intra-inflorescence allocation: racemes with greater investment in basal fruits displayed a stronger trade-off with distal investment than did racemes that made smaller initial investments. This trade-off was (a) much stronger for ovule number than for seed number, (b) ameliorated but not erased by resource addition, and (c) exacerbated by resource reduction. There was large and seemingly erratic variation across fruit positions in ovule fertilization and seed set following both natural and supplemental pollination. CONCLUSIONS In S. armeria, allocation to reproductive traits within the inflorescence is influenced by dynamic trade-offs in resource allocation between early and late fruits, and may also be subject to inherent architectural effects. Large, unpredictable variation among fruits in fertilization success and seed set may influence the evolution of inflorescence size, ovule number and floral dimorphism.
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Affiliation(s)
- Rowan H Brookes
- School of Biological Sciences, Monash University, Melbourne, Victoria 3800, Australia.
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12
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Forrest J, Thomson JD. Consequences of variation in flowering time within and among individuals of Mertensia fusiformis (Boraginaceae), an early spring wildflower. AMERICAN JOURNAL OF BOTANY 2010; 97:38-48. [PMID: 21622365 DOI: 10.3732/ajb.0900083] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Climate change is causing many plants to flower earlier in spring, exposing them to novel selection pressures, including-potentially-pollinator shortages. Over 2 years that contrasted in timing of flowering onset, we studied reproductive strategies, pollen limitation, and selection on flowering time in Mertensia fusiformis, a self-incompatible, spring-flowering perennial. Plants opened most of their flowers early in the flowering period, especially in 2007, the early year; but selection favored early-flowering individuals only in 2008. However, resource allocation to early vs. late seed production was flexible: In 2008, but not 2007, early flowers on a plant produced more and heavier seeds. Late flowers were capable of equal seed production if fertilization of early ovules was prevented, suggesting that late flowers serve a bet-hedging function. Evidence for pollen limitation was weak, although there was a tendency for early flowers to be pollen-limited in 2007 and for late flowers to be pollen-limited in 2008. Poor reproductive success in 2007 was likely attributable less to pollen limitation than to frost damage to flowers. We suggest that plasticity in floral longevity and resource allocation among flowers will make this species resilient to short-term pollinator deficits; whether this will help or hinder future adaptation is unclear.
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Affiliation(s)
- Jessica Forrest
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Harbord Street, Toronto, Ontario, M5S 3G5, Canada; and Rocky Mountain Biological Laboratory, P.O. Box 519, Crested Butte, Colorado 81224 USA
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Ortiz PL, Berjano R, Talavera M, Arista M. The role of resources and architecture in modeling floral variability for the monoecious amphicarpic Emex spinosa (Polygonaceae). AMERICAN JOURNAL OF BOTANY 2009; 96:2062-73. [PMID: 21622325 DOI: 10.3732/ajb.0800417] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Determining the sources of floral variation is crucial to the understanding of floral evolution. Architectural effects and phenotypic plasticity in development can play an important role in intraplant floral variation, giving rise to gender dimorphism or sexual specialization. Amphicarpic plants have another source of floral variation that could also be influenced by positional effects. We studied the effects of resource availability and architecture in intraplant floral variability in two ecotypes of the amphicarpic Emex spinosa. Male flowers were smaller than females, irrespective of position or resource availability. Emex spinosa shows gender dimorphism not influenced by positional effects. Flower size differences among positions were mainly due to architecture, because the effects of resources on flower size were minimal. Architectural effects caused a decrease in female flower size from ground to apical positions but an increase in most male traits that resulted in sexual specialization at the end of flowering. In general, the ecotypes were similarly affected by resources or architecture. Differences between subterranean and aerial female flowers seem also to be a consequence of architecture. Our results contribute to the evidence that resource limitation is an overestimated effect and that architectural effects must be considered in studies of floral or fruit variation.
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Affiliation(s)
- Pedro L Ortiz
- Departamento de Biología Vegetal y Ecología, Universidad de Sevilla, Apdo. 1095, 41080 Sevilla, Spain
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Sadras VO, Denison RF. Do plant parts compete for resources? An evolutionary viewpoint. THE NEW PHYTOLOGIST 2009; 183:565-574. [PMID: 19413690 DOI: 10.1111/j.1469-8137.2009.02848.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Simultaneously growing sinks are thought to compete for plant resources. Negative correlations, for example between grain number and stem mass in cereals, indeed resemble competition; but is the notion of intra-plant competition evolutionarily justified? Here we review intra-plant competition in light of two aspects of evolutionary biology: (a) major transitions that led to the reorganization of evolutionary individuals (e.g. isolated DNA molecules and independent cells) into new units of adaptation (e.g. chromosomes and multicellular organisms) with associated constraints to intra-individual conflict; and (b) genomic conflicts within individual plants with implications for resource allocation. Against this background, we look at apparent competition among genetically identical plant parts, and conclude that plants might use competition-like mechanisms to allocate resources, but only to the extent that these proximate mechanisms enhance overall plant fitness. In dealing with apparent competition among genetically different plant structures, we emphasize developing seeds attached to the same maternal plant, and the determination of yield components in annual crops. We propose that competition-like mechanisms among genetically different plant parts have been strongly shaped by the evolution of genomic conflict between parent and offspring, between female and male parents, and among siblings. By defining the number and potential size of grain simultaneously and before fertilization, a strong maternal control of resource allocation is exerted that favours uniform offspring size and partially counteracts genomic conflict.
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Affiliation(s)
- Victor O Sadras
- South Australian Research and Development Institute, Waite Campus, GPO Box 397, Adelaide 5001, Australia
| | - R Ford Denison
- Ecology Evolution and Behavior, University of Minnesota, 1987 Upper Buford Circle, Saint Paul, MN 55108, USA
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