Amino Acid Concentrations in Extrafloral Nectar of Impatiens Sultani Increase after Simulated Herbivory
1990
Smith, Lisa L. | Lanza, Janet | Smith, Garon C.
In many plants, extrafloral nectars attract ants that protect the plant from herbivory. Previous work indicates that both sugars and amino acids contribute to ant attraction and that herbivory may affect nectar production or composition. This study was designed to measure the effect of defoliation on sugar and amino acid concentrations in the extrafloral nectar of Impatiens sultani. Twenty—nine fall—raised plants and 45 spring—raised plants were subjected to varying degrees of defoliation in which 25, 50 or 75% of each leaf was removed. Extrafloral nectar was collected immediately before and 24 h after defoliation for the fall—raised plants; additionally, nectar was collected 24h before and 48 and 72 hr after defoliation in the spring—raised plants. Nectars were analyzed for sugar and amino acid content by means of high—pressure liquid chromatography (HPLC). Twenty four hours after defoliation, amino acid content increased dramatically in plants subjected to all three levels of defoliation' amino acid concentrations of nectars 72 h after defoliation were indistinguishable from predefoliation levels. No change in sugar concentrations or nectar volumes was detected. Additional work is needed to determine if the increase in amino acid is adaptive and serves to attract more plant protectors.
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