Little information is available concerning physiological responses of Kentucky bluegrass (Poa pratensis L.) (KBG) cultivars to salinity. Growth and physiological responses of ‘Limousine’ and ‘Kenblue’ KBG to a range of salinity levels were investigated. Grasses were grown in solution culture and exposed to salinity levels of 2.2, 5.2, 8.2, 11.2, and 14.2 dS m−1 for 10 wk. Though both cultivars exhibited increased leaf firing with increasing salinity, Limousine exhibited less leaf firing than Kenblue at salinity levels above 5.2 dS m−1 In addition, salinity levels that caused 25% shoot growth reduction were 3.2 dS m−1 for Kenblue and 4.7 dS m−1 for Limousine, indicating that Limousine has better salinity tolerance. Under moderate (8.2 dS m−1) salinity stress, Limousine produced ∼50% more root growth than Kenblue. Water relations diverged between cultivars at 8.2 and 14.2 dS m−1, as Limousine had higher leaf water and osmotic potentials, as well as more positive turgor. While glycinebetaine was not detected in either cultivar, proline increased in leaves with increasing salinity, and was higher in Kenblue than Limousine at 8.2, 11.2, and 14.2 dS m−1 This suggests that compatible solute accumulation is not a salinity tolerance mechanism of KBG, and that proline accumulation is merely an indication of salt injury. Limousine maintained 52% lower shoot Na+, 30.4% lower Cl−, and 52% higher shoot K+/Na+ ratio than Kenblue at the highest salinity level. These results suggest that salinity tolerance in KBG is largely attributable to maintenance of higher root growth, and more positive turgor, higher K+/Na+ ratio, and less Cl− accumulation in shoots. These traits may serve as useful selection criteria in breeding efforts to develop salt tolerant KBG.

High dimensional quantum states are of fundamental interest for quantum information processing. They give access to large Hilbert spaces and, in turn, enable the encoding of quantum information on multiple modes. One method to create such quantum states is parametric down-conversion (PDC) in waveguide arrays (WGAs) which allows for the creation of highly entangled photon pairs in controlled, easily accessible spatial modes, with unique spectral properties.In this paper we examine both theoretically and experimentally the PDC process in a lithium niobate WGA. We measure the spatial and spectral properties of the emitted photon pairs, revealing correlations between spectral and spatial 6

It is demonstrated that neither deletion of HO-2 nor BK channels affect acute, sustained, and chronic vascular responses to alveolar hypoxia in the lung.

Freezing tolerance is an important trait that determines geographical adaptation of a turfgrass. This study was conducted to assess the relative freezing tolerance, seasonal changes in freezing tolerance (LT50), and winter survival of six cultivars of buffalograss [Buchloë dactyloides (Nutt.) Engelm.]. The cultivars 91‐118, Tatanka, Texoka, Stampede, UCR‐95, and 609 were grown in the field at Fort Collins, CO. From September 1998 to April 1999 and from October 1999 to May 2000, stolons were sampled monthly from each plot and subjected to laboratory freezing tests. Survival and recovery following the freezing test indicated that all cultivars had similar LT50 in September and gradually increased in winter hardiness during fall. However, the capacity to acclimate and the maximum freezing tolerance were significantly different among the cultivars. Ranking of grasses for mean LT50 (°C) was Tatanka (−18.1) = 91‐118 (−18.0) ≤ Texoka (−17.1) < 609 (−14.4) < Stampede (−12.4) < UCR‐95 (−9.2) during midwinter in 1998‐1999 and Texoka (−21.7) = 91‐118 (−21.6) = Tatanka (−21.0) < 609 (−15.8) = Stampede (−15.1) < UCR‐95 (−14.0) during midwinter in 1999‐2000. Following freezing treatments, Tatanka and 91‐118 maintained a higher relative shoot and root regrowth than other cultivars. Root regrowth was reduced by freezing to a greater extent than shoot regrowth for all cultivars. Field winter survival, a measure of winter hardiness, in 1998, 1999, and 2000 was generally in agreement with laboratory test results, showing that Stampede, 609, and UCR‐95 were more susceptible to winterkill than 91‐118 and Tatanka. The differences in freezing tolerance among the cultivars tested indicates substantial intraspecific variation that may be used for breeding improvement.

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.