Cyperus brevifolius is a perennial weed in turf grass on golf courses. Recently, some populations of C. brevifolius have been found to survive after application of sulfonylurea herbicides in turf grass. In this research, responses to halosulfuron-methyl and flazasulfuron sulfonylurea herbicide, were examined and the gene encoding acetolactate synthase (ALS) was determined in four accessions that were collected from the survived populations. All the four accessions survived after the treatment with halosulfuron-methyl at a recommended dose of turf in a pot experiment. Analysis of ALS gene revealed that the ALSs of the five accessions have amino acid substitutions; either of Asp376Glu, Pro197Ser or Trp574Leu, which are known to cause sulfonylurea resistance. Thus, sulfonylurea resistant biotypes were found in C. brevifolius in turf grass in Japan, and the resistance was assumed to be caused by amino acid substitutions of ALSs.
By establishing levees with Zoysia japonica “Asagake”, mowing frequency could be reduced from four (i.e. mowing with a grass cutter in May, June, July and September). to three (i.e. May, July, and September) times a year. Number of plants species was similar between levees, but lawn-covered levees had fewer large perennial plants and no woody plants. The “Asagake” levee exhibited the initial stages of secondary succession with less regeneration of large perennials and woody plants. On the other hand, weed-covered levees, which exhibited greater ecological succession, with large perennials and woody plants that regenerated shortly after mowing.
In this study, we used to turf grasses which removing 137Cs, 134Cs and 133Cs from the red clay as relatively safe and environmentally method. We have conducted two experiments (137Cs, 134Cs contaminated field test in Fukushima prefecture and pot experiment in 133Cs added soil under controlled condition) to determine the ability of four grass species (Festuca arundinacea Schre., Lolium perenne L., Poa pratensis L., Cyno dactylon Pers.) to extract Cs isotopes from contaminated soil. The result shows that 1) 137Cs, 134Cs and 133Cs uptake by all species increases according to the level of Cs concentration of soil; 2) all turf grasses became a low to translocation ability of 133Cs to stem as compared with Brassica napus L.; 3) all species occur growth inhibition from the 500 mg/kg 133Cs treatment; 4) the effective usage of oxalic acid on the phytoremediation of 133Cs was not proved. In conclusion, the turf grasses were proved to have low accumulation capability for Cs isotopes. The essence aspect of the problem is to find the workable technique to dissolving out the Cs isotopes which strongly absorbed by the soil, and it requires for further investigation.