ABSTRACT
Variability of allozymes (1170 individuals, 47 populations) and chloroplast DNA (692 individuals, 29 populations) was examined in native European and introduced North American populations of Epipactis helleborine (Orchidaceae). At the species level, the percentage of allozyme loci that were polymorphic (P(99)) was 67%, with a mean of 2.11 alleles (A) per locus, and an expected heterozygosity (H(exp)) of 0.294. At the population level, mean P(99) = 56%, mean A = 1.81, and mean H(exp) = 0.231. Although field observations suggest that self-pollination occurs frequently, populations had a genetic structure consistent with Hardy-Weinberg expectations and random mating (mean F(IS) = 0.002). There was significant deviation from panmixia associated with population differentiation (mean F(ST) = 0.206). The distribution of two chloroplast haplotypes showed that 15 of the 29 populations were polymorphic. Using both nuclear and organelle F(ST) estimates, a pollen to seed flow ratio of 1.43â:â1 was calculated. This is very low compared with published estimates for other plant groups, consistent with the high dispersability of orchid seeds. Finally, there was no evidence for a genetic bottleneck associated with the introduction of E. helleborine to North America.
ABSTRACT
Fifteen adults, hospitalized for fiberoptic endoscopy studies, were tested under two conditions using impedance audiometry. The first series of tests was conducted prior to the fiberoptic studies and sedation; the second immediately following examination, approximately 20 minutes after sedation with diazepam (Valium) and meperidine (Demerol) hydrochloride. Sedation with diazepam and meperidine failed to have a significant effect on tympanometry, static compliance, or differential loudness. These drugs were therefore considered effective sedatives for conducting impedance studies on difficult-to-test patients. This procedure is not recommended as a routine procedure and should be done only as a last resort.
