Journal of Chemical Ecology, Vol. 19, No. 6, 1993 ALKALOIDAL RESPONSES TO DAMAGE IN Nicotiana NATIVE TO NORTH AMERICA IAN T. BALDWIN* and THOMAS E. OHNMEISS Department of Biological Sciences SUNY at Buffalo Buffalo, New York 14260-1300 (Received September 28, 1992; accepted January 27, 1993) Abstract--We performed field tests of alkaloid induction in Nicotiana atten- uata plants growing in southwestern Utah with mimicry of the two major types of damage inflicted by invertebrate and vertebrate herbivores: leaf dam- age and stalk removal, respectively. In undamaged plants, seasonal increases in leaf nicotine content occurred at a rate of 0.046% leaf dry mass/day. Leaf damage doubled the accumulation rate to 0.086-0.138 % leaf dry mass/day, while stalk removal resulted in a quadrupling of the accumulation rate to 0.206% leaf dry mass/day. These damage-induced increases in nicotine accu- mulation are significantly larger than between-plant and phenological varia- tions. Leaf damage to the noruicotine-(N, repanda and N. trigonophylla) and anabasine-accumulating (N. glauca) Nicotiana species native to North Amer- ica resulted in 1.5- to 5-fold increases in their principal leaf alkaloid pools. We conclude that alkaloid induction is not limited to nicotine-accumulating Nicotiana species and that herbivores feeding on previously damaged plants are likely to encounter tissues with alkaloid titers significantly higher than those of undamaged plants. Key Words--Damage-induced responses, Nicotiana attenuata, Nicotiana repanda, Nicotiana glauca, Nicotiana trigonophylla, nicotine, nomicotine, anabasine, herbivory. INTRODUCTION Most of the biosynthetic classes of secondary metabolites are induced by leaf damage (Baldwin, 1993; Rosenthal and Berenbaum, 1991; Tallamy and Raupp, 1991) in at least some plants. These damage-induced metabolites may be part *To whom correspondence should be addressed. 1143 0098-0331/93/0600-1143507.00/0 9 1993PlenumPublishing Corporation