Effect of Pollination Success on Floral Longevity in the Orchid Calypso bulbosa OrchidaceaeReportar como inadecuado

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color, staminate, limitations, mimicry, biology, duration, individual flowers, pistillate phases, reproduction, fruit production

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Subject-Keyword: color staminate limitations mimicry biology duration individual flowers pistillate phases reproduction fruit production

Type of item: Journal Article Published

Language: English



Description: The lifespan of an individual flower is often affected by pollination success. Species differ regarding whether male function pollen removal, female function pollen deposition, or both trigger floral senescence. We studied senescence in the single- flowered, deceptive orchid Calypso bulbosa by manipulating the degree of male and female reproductive success. We found that deposition of any amount of pollen resulted in dramatic changes in shape and color within 4 d, whereas unmanipulated flowers and those that had had pollinia removed remained unchanged for 8-11 d after treatment. Selection may favor the reproductive function that is less easily satisfied as the trigger for senescence, because a flower that senesces after accom- plishment of this function is likely to have already succeeded at the more easily satisfied one. Deceptive i.e., rewardless flowers are more likely to satisfy male than female function since the latter requires that a pollinator be fooled twice, first to pick up pollen and second to deposit it. A survey of naturally pollinated Calypso showed that male function, pollinium removal, was more likely to occur than female function, deposition 95% vs. 66% of visited flowers; thus floral senescence in Calypso is triggered by achievement of the function less likely to succeed. Studies of senescence triggers in species in which female function is more likely to be achieved than male are necessary to further test this hypothesis.

Date created: 1995

DOI: doi:10.7939-R3WW0W

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Rights: This version of this article is open access and can be downloaded and shared. The original authors and source must be cited.

Autor: Proctor, H.C. Harder, L.D.

Fuente: https://era.library.ualberta.ca/


AmericanJournalofBotany82(9): 1131-1136.
HARDER Department ofBiologicalSciences,University ofCalgary, Calgary, Alberta,CanadaT2N 1N4 Thelifespan ofan individualflower is oftenaffected bypollination success.Speciesdiffer regarding whether malefunction (pollenremoval),femalefunction (pollendeposition), orbothtrigger in thesinglefloralsenescence. We studiedsenescence flowered, deceptiveorchidCalypsobulbosabymanipulating thedegreeofmaleand femalereproductive success.We found indramatic thatdeposition ofanyamountofpollenresulted changesin shapeandcolorwithin4 d,whereasunmanipulated and thosethathad had polliniaremovedremainedunchanged flowers for8-11 d aftertreatment. Selectionmayfavorthe reproductive function thatis lesseasilysatisfied as thetrigger forsenescence, becausea flower thatsenescesafteraccomplishment ofthisfunction is likelyto have alreadysucceededat themoreeasilysatisfied one.
Deceptive(i.e.,rewardless) be fooledtwice,first flowers are morelikelyto satisfy malethanfemalefunction sincethelatterrequiresthata pollinator to pickup pollenand secondto depositit.A surveyofnaturally pollinatedCalypsoshowedthatmalefunction, pollinium thusfloralsenescence removal,was morelikelyto occurthanfemalefunction, deposition (95% vs.
66% ofvisitedflowers); in Calypsois triggered in speciesin by achievement of thefunction less likelyto succeed.Studiesof senescencetriggers whichfemalefunction is morelikelyto be achievedthanmaleare necessary to further testthishypothesis. The lifespanofan individualflower, theperiodduring spans thatare independent of whethermale or female whichit is attractiveand available to pollinators, can pollinationfunctions have been achieved.For example, measurefromminutesto months(van derPijl and Dod- theCommelinaceae, and Pontederiaceae, Convolvulaceae, son, 1966).
At the end of its lifea flowermay change Tumeraceaeh...

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