Understanding turfgrass response to silicon (Si) application under salinity conditions is important to find a way to improve turfgrass salt tolerance for turf management. The objective of the study was to investigate effects of increasing amendment concentrations of Na2SiO3 on turf growth and distribution of Na+ and K+ in seedlings of kentucky bluegrass (KBG) (Poa pratensis L.) under salinity stress. This growth chamber experiment was consisted of a control (no salinity and no Si) and five Si amendment treatments (0, 0.24, 0.48, 0.72, and 0.96 g Si/kg saline soil) under 10 g·kg−1 salinity conditions. Seed germination rate was significantly increased after 12 d under 0.48 g·kg−1 Si treatment. Plant height and canopy coverage were increased under 0.72 g·kg−1 Si treatment after 40 and 44 d of treatment, respectively, and tiller number was increased under 0.96 g·kg−1 Si treatment compared with 0 Si under saline conditions. With the supplement of Si at 0.48 to 0.96 g·kg−1, the ratio of Na+/K+ in shoots was decreased and individual leaf area was increased compared with 0 Si under saline conditions. The increase in individual leaf area was mainly the result of the increase in the leaf blade length. The concentration of K+ in shoots was significantly increased, whereas the concentrations of Na+ in roots were significantly decreased under all Si amendment treatments. The content of K+ was higher in shoots than in roots, but the ratio of Na+/K+ in roots was higher than in shoots in all Si amendment treatments. The results indicate that under saline conditions, Si induced the transfer of K+ from roots to shoots but inhibited the absorption and transfer of Na+, which may contribute to better turf quality and growth with Si treatment under saline conditions.
The objective of this study was to determine physiological traits for drought survival and post-drought recovery upon re-watering in two C3 perennial grass species, kentucky bluegrass [KBG (Poa pratensis)] and perennial ryegrass [PRG (Lolium perenne)]. Plants were maintained well watered or exposed to drought stress by withholding irrigation and were then re-watered in a growth chamber. KBG had significantly higher grass quality and leaf photochemical efficiency, and lower electrolyte leakage than PRG during 20 days of drought. After 7 days of re-watering, drought-damaged leaves were rehydrated to the control level in KBG, but could not fully recover in PRG. KBG produced a greater number of new roots, while PRG had more rapid elongation of new roots after 16 days of re-watering. Superior drought tolerance in KBG was associated with osmotic adjustment, higher cell wall elasticity, and lower relative water content at zero turgor. Osmotic adjustment, cell wall elasticity, and cell membrane stability could play important roles in leaf desiccation tolerance and drought survival in perennial grass species. In addition, post-drought recovery of leaf hydration level and physiological activity could be associated with the accumulation of carbohydrates in leaves and rhizomes during drought stress and new root production after re-watering.