Abstract Detail



Ecology

Koptur, Suzanne [1], Primoli, Andrea Salas [2], Pimienta, Maria [3].

Defoliation in perennial plants: predictable and surprising results in Senna species.

      When some plants are defoliated, they may suffer by reaching a smaller final size than if they had not been damaged.  Other plants may compensate for damage, and put more energy into growth than they may have otherwise, ending up the same size as if they have never been damaged.  And others may overcompensate, ending up larger after defoliation than if they had been spared from damage.  We investigated the response of Senna species to defoliation, comparing the responses of two native and several ornamental congeners, all of which grow locally in southern Florida. Senna (Fabaceae) is a widespread genus that has received much attention from systematists and ecologists. Many Senna spp. bear foliar nectaries that attract beneficial insects that protect them from herbivores. We grew different species from seed in a greenhouse and subjected them to three levels of defoliation for a period of several months, to measure effects of leaf area removal on plant height, number of leaves, number of flowers, and number of extrafloral nectaries.  Defoliation treatments started after seedlings were established, and as new leaves were produced, each received its assigned level of leaf removal. As expected, the greater the level of damage, the lower the final plant height. In some species we observed greater numbers of leaves produced with moderate defoliation. Additionally, the number of extrafloral nectaries increased in some species with defoliation, suggesting that extrafloral nectar production may be an inducible defense in those species. 


1 - Florida International University, Department Of Biological Sciences, 11200 SW 8th St., Miami, FL, 33199, United States
2 - 2259 Tequesta Lane, Miami, FL, 33133, United States
3 - 1429 SW 5th TR, Biology Department, Miami, FL, 33199, US

Keywords:
defoliation
Compensation
extrafloral
nectaries
legume
Fabaceae
Induction
defense.

Presentation Type: Oral Paper
Number: ECO7001
Abstract ID:870
Candidate for Awards:None


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