| In order to study the resistance to sulfur dioxide (SO2), four warm-season turfgrasses [Tall fescue (Festuca arundinacea),Perennial ryegrass (Loliumperenne L.),Creeping bentgrass(Agrostis stolonifera), and Kentucky bluegrass(Poa apratensis L)], which are commonly used for city greening, were selected as target species for investigation. The turfgrasses were treated with SO2 using the artificial simulated fumigation method, and five concentration levels of SO2, including CK (natural state), S1 (0.375ppm), S2 (1.125ppm), S3 (1.875ppm) and S4 (2.625ppm), were designed in this study. Content of total chlorophyll, MDA, proline,soluble protein, soluble sugar, sulfur,superoxide dismutase(SOD), activites of peroxidase(POD), catalase(CAT) were tested. The comprehensive evaluation for the resistance of four turfgrasses to SO2 were studied data analyses by mathematical methods such as Correlation analysis and fuzzy mathematics method etc.The main results are as the followings.(1) The visible injury symptoms caused by different SO2 concentration treatment were obviously different on four turfgrasses. The injured areas appeared on the Tall Fescue leaves was yellow,the separated part of injured and normal was brown; Brown and yellow spots appeared between the veins of Perennial ryegrass; The leaves of Creeping bentgrass began wilting, chlorosis, lose their luster; the leaves of Kentucky bluegrss become yellow,and the turfgrass density declines.(2) The chlorophyll of Tall Fescue, Perennial ryegrass,Creeping bentgrass, Kentucky bluegrss content become low under the SO2 stress.(3) Along with increase of SO2 concentration, MDA content in leaves increased gradually, and Tall Fescue, Perennial ryegrass on the S3 were maximum;Then Creeping bentgrass, Kentucky bluegrss on the S4 were maximum.(4) The activity of SOD,POD,CAT about Tall Fescue appeared an increasing and then a decreasing trend with enhancing of the concentration of the SO2,and on the S1 were maximum;the activity of SOD,POD other turfgrasses decreased, moreover were always lower than that of the check; CAT activity of Perennial ryegrass, Creeping bentgrass increased and then decreased, howwver Kentucky bluegrass decreased directly.(5) While the concentration of SO2 rose, The content of proline in Tall Fescue, Perennial ryegrass increase with enhanced of SO2,and on the S4 reached the highest,compared with check, increased by 222.52%,210.16%, the proline content in each treatment of Creeping bentgrass were higher than that of the check, The biggest increase in S2 processing, increased by 51.63%. Proline content in Kentucky bluegrass was only increased in S1 treatment, a rise of 50.41%.(6) The soluble sugar content of Tall Fescue, Perennial ryegrass, Creeping bentgrass, Kentucky bluegrss decreased gradually with elevated concentrations of SO2 under the SO2 stress, compared with CK, decreased by 19.9%,22.83%,27.33%,32.88% in highest concentration.(7) After SO2 treatment, The protein content is gradually reduced with SO2 increasing, the soluble protein content in Tall Fescue, Perennial ryegrass, Creeping bentgrass, Kentucky bluegrass, compared with CK, respectively decreased by 27.33%,31.12%, 33.82%,51.66% in highest concentration.(8) The sulfur content of every turfgrass gradually increased with SO2 increasing.The sulfur content of Kentucky bluegrass was slightly less than Perennial ryegrass in addition to the S1 processing, sulfur content in turfgrass under other processing are the largest.(9) Synthetical evaluation result based on fuzzy mathematics and subordinate function analysis suggested that the resistance of the four turfgrasses to SO2 was ordered in sequence from strong to weak as following:Tall fescue> Perennial ryegrass> Creeping bentgrass> Kentucky bluegrass. Considering,tall fescue on the ability of the sulfur resistance and the capacity of absorbed pollutants are all stronger than other three turfgrasses, so in the urban greening choose that as the priority turfgrasses. |
