Pollen size and pistil length variation: the influence of flower-functionality and pollination system.

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

ORGANISMS DIVERSITY & EVOLUTION

SPRINGER HEIDELBERG

Año: 2009 vol. 9 p. 75 - 82

1439-6092

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. o´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.