Carbon Isotope Discrimination of Three Kentucky Bluegrass Cultivars with Contrasting Salinity Tolerance

Abstract

tolerant cultivars showing less growth reduction than sensitive cultivars under saline conditions (Qian et al., We evaluated leaf C isotope discrimination as affected by salinity 2001; Suplick-Ploense et al., 2002). Growth reduction among three Kentucky bluegrass (Poa pratensis L.) cultivars that differ in their salt tolerance. 'Moonlight', 'NorthStar', and 'P-105' under salt stress could be attributed to excessive ion Kentucky bluegrass (KBG) were grown in solution culture and exaccumulation in the plant tissue and/or to water stress posed to salinity levels of 2.0, 5.0, 8.0, 11.0, and 14.0 dS m Ϫ1 for 12 due to low external osmotic potential resulting from sawk. All cultivars exhibited increased leaf firing with increasing salinity. linity. However, Moonlight and NorthStar exhibited less leaf firing than Selection for salt tolerant species and/or cultivars in P105 at all salinity levels. The salinity levels that caused 25% shoot the field is time consuming and difficult due to spatial growth reduction were 4.9 dS m Ϫ1 for NorthStar and Moonlight and and temporal variations of salinity level and salt compo-4.1 dS m Ϫ1 for P105, indicating that Moonlight and NorthStar have sition. Measurement of C isotopic composition and ⌬ better salinity tolerance than P105. When salinity level was in the in nonstressed, controlled environments has been found range of 2.0 to 8.0 dS m Ϫ1 , Moonlight produced 1.9-fold more root mass than NorthStar, and NorthStar exhibited 3.9-fold more root mass to be related to water use efficiency in the field, producthan P105. When salinity exceeded 8.0 dS m Ϫ1 , NorthStar had similar tion under water stress conditions, and plant-environroot mass as Moonlight, and both showed greater root mass than mental interactions in many cool-season grasses (Far-P105. Cultivar P105 had a higher C isotope discrimination (⌬) than quhar and Richards, 1984; Johnson et al., 1990; Johnson Moonlight and NorthStar under nonsaline conditions (Ͻ2 dS m Ϫ1 )and Bassett, 1991). Ebdon et al. (1998) reported that C but a lower ⌬ than Moonlight and NorthStar at 11.0 dS m Ϫ1 salinity.isotope discrimination is a useful criterion for assessing The great reduction in ⌬ of P105 as salinity increased suggests that water use efficiency in KBG. It is unknown if ⌬ is associsalinity induced a greater degree of stomatal resistance that provided ated with KBG salt tolerance and if low ⌬ of KBG less opportunity for discrimination against the heavier isotope. Carbon grown under nonsaline conditions would provide an isotope discrimination may serve as a useful selection criterion in breeding efforts to develop salt tolerant KBG.

Interaction Effects of Salinity and Mowing on Performance and Physiology of Bermudagrass Cultivars

“…The decline in clipping yield under higher salinity was more severe and more rapid at lower mowing heights for all cultivars (Fig. In previous literature, salinity levels that resulted in 25% clipping yield reduction have been used as indicator of salinity tolerance (Qian et al, 2001(Qian et al, , 2004(Qian et al, , 2007Suplick-Ploense et al, 2002;Lee et al, 2004a, b;Fu et al, 2005;Shahba, 2010). Clipping yield decreased linearly with increasing salinity level under the three mowing regimes.…”

“…Most studies comparing salinity tolerance among different grass species have been conducted under a single mowing regime or under unmowed conditions (Youngner et al, 1967;Marcum, 2001;Qian et al 2004;Shahba, 2010). The interaction eff ects of salinity and mowing on bermudagrass are not well understood.…”

Salinity Effects on Seed Germination and Vegetative Growth of Greens‐Type Poa annua Relative to Other Cool‐Season Turfgrass Species

“…Qian et al (2004) studied salinity tolerance of three Kentucky bluegrass cultivars using hydroponics and reported that Northstar and Moonlight were relatively more salt tolerant than ‘P105’. Additionally, Northstar was found to be more salt tolerant than Moonlight based on salt damage ratings in field studies (Rose‐Fricker and Wipff, 2001).…”

“…Nine greens‐type P. annua experimental lines (PSU 96‐1‐9, PSU 98‐3‐30, PSU 98‐4‐21, PSU 99‐2‐5, PSU 99‐3‐19, PSU 99‐9‐21, PSU 99‐11‐6, PSU 01‐1‐46, and PSU 05‐1‐14) were chosen to represent the high to low range of salinity tolerance observed in a previous long‐term salinity stress study (Dai et al, 2008). Inclusion of other cool‐season turfgrass cultivars was based on published salt studies: three creeping bentgrass cultivars (Mariner, Seaside II, and ‘Penncross’) (Marcum, 2001), two Kentucky bluegrass cultivars (Moonlight and Northstar) (Qian et al, 2004; Rose‐Fricker and Wipff, 2001), and one perennial ryegrass cultivar (Charger II) (Rose‐Fricker and Wipff, 2001) (Table 1).…”

Relationship between Carbon Isotope Discrimination and Grain Yield in Spring Wheat under Different Water Regimes and under Saline Conditions in the Ningxia Province (North‐west China)

“…In cotton ( Gossypium hirsutum L.), Brugnoli and Lauteri (1991) demonstrated that the effect of salt stress on Δ was mostly because of the reduction of stomatal conductance. In Kentucky bluegrass ( Poa pratensis L.) Δ was found to be higher in salt tolerant genotypes (Quian et al. 2004).…”