Influence of flower functionality and pollination system on the pollen size-pistil length relationship

FERNÁNDEZ, V., ASTEGIANO, J. & GALETTO, L.

Organisms Diversity and Distribution

Año: 2008

Abstract Twenty-fivebioticallypollinatedplantsoftheChacoSerranoForest(Co´rdoba, Argentina)werestudiedinorderto analyze whether‘flowerfunctionality’isrelatedtotherelationshipbetweenpollensizeandpistillength.Becauseflower functionalitymayactontherespectivemeanvaluesofpollensizeandpistillengthratherthanonintraspecific variationinthesetraits,weexpected(1)ahighpositivecorrelationbetweenpollensizeandpistillengthinasetof sympatricspecies,independentoftheirdegreeofpollinationspecializationorgeneralization;and(2)nointerspecific correlationbetweenthecoefficientsofvariation(CVs)ofthosetraits.Ontheotherhand,ontheassumptionthat pollinatorsareinfluencingthevariationinfloraltraits(e.g.inpistillength)weexpectedlowermeanphenotypic variationofpollensizeandpistillengthinpollination-specialistplantsthaninpollination-generalistones.Apositive correlationbetweenpollensizeandpistillengthwasfoundforthesetofspecies,butnotbetweentheCVsofthese traits. Thistrendwasmaintainedwhenpollination-specialistplantswereanalyzedseparately,butnostatistical significancewasobtainedforthecorrelationinpollination-generalistplants.Contrarytoourexpectations,pollination- specialistplantsdidnotshowlessmeanintraspecificvariationinfloraltraitsthanpollination-generalistplants. Therefore,therelationshipbetweenpollensizeandpistillengthamongspeciessuggeststhatthepollinationsystemmay be oflessimportanceasaselectiveforcethanflowerfunctionality. r 2009 Gesellschaftfu¨r BiologischeSystematik.PublishedbyElsevierGmbH.Allrightsreserved. Keywords: Coefficient ofvariation;Functionalcorrelation;Pistillength;Pollensize;Pollinationsystems;Pollinators Twenty-fivebioticallypollinatedplantsoftheChacoSerranoForest(Co´rdoba, Argentina)werestudiedinorderto analyze whether‘flowerfunctionality’isrelatedtotherelationshipbetweenpollensizeandpistillength.Becauseflower functionalitymayactontherespectivemeanvaluesofpollensizeandpistillengthratherthanonintraspecific variationinthesetraits,weexpected(1)ahighpositivecorrelationbetweenpollensizeandpistillengthinasetof sympatricspecies,independentoftheirdegreeofpollinationspecializationorgeneralization;and(2)nointerspecific correlationbetweenthecoefficientsofvariation(CVs)ofthosetraits.Ontheotherhand,ontheassumptionthat pollinatorsareinfluencingthevariationinfloraltraits(e.g.inpistillength)weexpectedlowermeanphenotypic variationofpollensizeandpistillengthinpollination-specialistplantsthaninpollination-generalistones.Apositive correlationbetweenpollensizeandpistillengthwasfoundforthesetofspecies,butnotbetweentheCVsofthese traits. Thistrendwasmaintainedwhenpollination-specialistplantswereanalyzedseparately,butnostatistical significancewasobtainedforthecorrelationinpollination-generalistplants.Contrarytoourexpectations,pollination- specialistplantsdidnotshowlessmeanintraspecificvariationinfloraltraitsthanpollination-generalistplants. Therefore,therelationshipbetweenpollensizeandpistillengthamongspeciessuggeststhatthepollinationsystemmay be oflessimportanceasaselectiveforcethanflowerfunctionality. r 2009 Gesellschaftfu¨r BiologischeSystematik.PublishedbyElsevierGmbH.Allrightsreserved. Keywords: Coefficient ofvariation;Functionalcorrelation;Pistillength;Pollensize;Pollinationsystems;Pollinators