Osmotic adjustment in Leymus cinereus cv. "Trailhead" under field conditions

Osmotic adjustment has been recognized to be an important adaptive response to water stress in higher plants. Although Leymus cinereus cv. "Trailhead" is reputedly a very drought-tolerant rangeland plant, its ability to adjust osmotically in the field has not previously been reported. This study examined the occurrence or not of osmotic adjustment in field-grown plants of Leymus cinereus cv. "Trailhead" during late spring in an arid zone of Patagonia. Plants of this species had been established in the field three years before. With this purpose, leaf laminae of this species were collected and pressure-volume curves made. Results showed turgor maintenance in the face of declining leaf water potentials (i.e., osmotic adjustment) in the study species. Even more, maximum pressure at maximum leaf water potential was increased during a 3-week-period. This response is typical of plants with a previous history of osmotic adjustment as a result of water stress.