To determine the traits associated with heat and disease tolerance in two creeping bentgrass (Agrostis palustris Huds.) cultivars, CY-2 and Penncross, disease index, turf quality, electrolyte leakage (EL), Electrical conductivity (EC) of dew water on the turf surface, and other mineral components present in their leaf blades in summer were examined. The number of spots caused by the dollar spot disease and the turf area damaged by brown patch in summer were fewer in CY-2 than in Penncross. The turf quality of CY-2 was also higher than that of Penncross. The EC values of dew water on the turf surface of CY-2 were constantly lower than those of Penncross. The difference between EC values in the two creeping bentgrass cultivars may be related to the difference between the turf qualities. Differences in EL from the leaf blade of the cultivars were not significant. In CY-2, the magnesium and calcium concentrations of the shaking extract solution and the leakage of these components from the leaf blade in middle position were lower than those in Penncross. This explains the difference in EC, EL, and turf quality between the two creeping bentgrass cultivars. The deterioration of turf in summer causes increased rate of mineral leakage from the leaves, and this can be detected by the increased EC values of dew water on the turf surface or higher magnesium and calcium concentrations of the shaking extract solution of the leaf blade in middle position. These factors may help us in characterizing the differences in heat and disease tolerance between cultivars.
Annual bluegrass (Poa annua L.) which derived from a putting green (GR) and an orchard (OR) was grown under field conditions from Sep., 2014 to May, 2015. GR and OR produced ripened seeds in Nov., 2014, Mar., Apr., May, 2015 and in Nov., Dec., 2014, Mar, Apr., May, 2015, respectively. Thousand grain weight (TGW), percentage of living seeds (PLS), germination rate in the incubator (GRI) and germination rate in the field (GRF) of the living seeds were measured in each times mentioned above. PLS of both GR and OR were higher than about 90%, regardless of times. The minimum and maximum values of the TGW were reached in May and Mar., 2015, respectively. The GRI values of GR (39.5±7.5% to 84.0±4.2%) were higher than those of OR (0% to 0.6±0.4%). On the other hand, GRF of GR was less than GRI, and the seed of OR was rarely germinated under field conditions. These results suggest that seed dormancy of GR is not so strong as compared to that of OR and the seed is possibly shifted to a primary, secondary and/or enforced dormancy depending on the environmental conditions.
This comparative study was designed to reveal the differences of physiological indicators (heart rate, blood pressure, cerebral blood flow by using a near-infrared spectroscopy (NIRS), and the salivary amylase activity), caused by being on either grassy turf or soil ground. The purpose of this study was to obtain basic data to demonstrate the effect of playground turf on sport and education environments. These indicators were measured in a resting state for six subjects while they were watching the turf or soil surface after having blocked the visual modality by wearing an eye mask. Although there were no differences in the two conditions heart rate and blood pressure, most subjects showed lower values of salivary amylase activity for turf. It was observed that the mean value and standard deviation for the time on turf ground was (20.7±3.3 (KU/L)) as compared to the soil ground (30.6±9.3 (KU/L)), with near statistical significance (p=0.055). There was a tendency towards a higher value at the time of being on the turf ground in the comparison of brain blood flow by NIRS. This tendency was especially evident at the center (9 ch, p<0.05) and the left side (13 ch, p<0.10) of the prefrontal area in the integration values of the cerebral blood flow, where a significant difference was observed.