Klemow, Kenneth M. 1984. WATER RELATIONS OF LIMESTONE-QUARRY AND OLD-FIELD HERBACEOUS PLANT SPECIES. Contributed paper: Pennsylvania Academy of Science meeting. Abstract: Proceedings of the Pennsylvania Academy of Science 58:110.
Herbaceous plants colonizing the Jamesville Limestone Quarry near Syracuse, New York are subjected to periodic drought due to shallow soil with a low water-holding capacity. To determine whether quarry-inhabiting plants differed from plants growing naturally in other habitats due to their water relations, stomatal resistance was examined in relation to soil-water depletion. Quarry species studied were Hieracium florentinum and Picris hieracioides. Non-quarry species were Plantago major and Dipsacus sylvestris. Quarry plants tended to deplete soil water more slowly than non-quarry plants. Picris stomata failed to close until the soil was very dry, suggesting that it is a drought-tolerating sppcies. Stomata of Hieracium closed when the soil was still comparatively moist, suggesting that it is a drought-evading, moisture-conserving species. Dipsacus was also a drought-tolerating species, and it seems unlikely that it is excluded from the quarry due to water relations. Plantago individuals were neither drought-tolerators nor drought-evaders and this species is probably excluded from the qunrry due to the lack of appropriate adaptations to periodic severe drought. Findings of this study emphasize that complex and contrasting adaptations allow plants to exploit a stressful habitat. Evolution of Picris and Hieracium has led to two different solutions to the problem of successfully colonizing shallow, dought-prone soils, such as those in the Jamesville quarry.