Abstract: A solution of 6-benzylaminopurine in a polar solvent dispersed in water and sprayed over the foliage of grass for the growth of grass roots in concentration of 25 to 300 p.p.m. The solution is sprayed onto the leaves and stems of grass at a rate at which 6-benzylaminopurine is applied in an amount of 2.5 to 30 mg. per m.sup.2 of turf.

Abstract: A sheet film is produced from a tubular thermoplastic resin film by cooling a molten tubular film of crystalline thermoplastic resin, for example, polypropylene, extruded downward from an annular die in direct contact simultaneously with cooling liquids on the outside and inside of the film, the cooling liquid on the outside being in an outside cooling liquid tank and in contact with the outside of the film and the cooling liquid on the inside flowing down along the surface of a mandrel provided through the outside cooling liquid tank and in contact with the inside of the film, a liquid level of the cooling liquid on the inside being kept higher by 5-15 mm than that of the cooling liquid on the outside; cutting open length wise one or two side ends of the film just before being flattened and folded by nip rolls thereby to discharge the cooling liquid from the inside; and removing the liquid attached to the surfaces of the resulting sheet films withdrawn by the nip rolls promptly.