Salt Stress Effects on Root Viability and Major Phytohormones in Leaves and Roots for Two Creeping Bentgrass Cultivars Differing in Salt Tolerance.

Salinity stress is becoming more challenging in turfgrass management with the increasing use of recycled water for irrigation. Creeping bentgrass (Agrostis stolonifera L.) is a turfgrass species that contains significant cultivar variation in salt stress tolerance but the mechanism related to this cultivar variation is not fully understood. A growth chamber study was conducted to evaluate salt ion concentrations, physiological responses and hormone analysis at 4, 8, and 12 dS/m in a relatively salt tolerant (‘Mariner’) compared to a salt sensitive cultivar (‘Penncross’) of creeping bentgrass. Greater salt tolerance was evident in ‘Mariner’ at 12 dS/m which showed significantly lower electrolyte leakage, higher relative water content, osmolality, photochemical efficiency and yield compared to ‘Penncross’. A higher K+ and lower Na+ content was maintained in leaves of ‘Marinar’ compared to ‘Penncross’ while roots of ‘Mariner’ maintained higher Ca2+ content under stressed and non-stressed conditions. ‘Mariner’ leaves showed an increased accumulation of abscisic acid (ABA), jasmonic acid (JA), salicylic acid (SA) and zeatin while roots maintained higher Indole acetic acid (IAA) and SA compared to ‘Penncross’. Our results suggests that differential regulation of phytohormone profiles may play an important role in salt stress adaptation and tolerance in creeping bentgrass.