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In this paper we study the climate change characteristics of rainstorm and risk assessment of rainstorm rainfall in Jinshan of Shanghai in recent 60 years with the daily rain data at Jinshan meteorological station from 1959 to 2016 by the methods of abrupt change test, morlet wavelet and so on. The results are as follows. (1) The rainstorm days had been increasing and rainstorm intensity had been increasing indistinctively in Jinshan in recent 60 years. The mutation of rainstorm days from low to high occurred in 1988. The first date of rainstorm had tended to occur early in the recent 60 years. Jinshan had been into the early occurrence stage of rainstorm since 1990s. The last date of rainstorm had tended to occur lately since the 21st century. (2) The risk probability and disaster intensity were the highest for typhoon rainstorm, followed by low pressure rainstorm. The high risk levels of warm sector rainstorm, stationary front rainstorm, low pressure rainstorm and typhoon rainstorm were 50-75 mm, 50-75 mm, 50-90 mm and 50-100 mm, respectively. The corresponding risk probabilities were 28.4%-100%, 28.9%-100%, 32.3%-100% and 33.6%-100%, respectively.

In this study, a myrosinase-producing strain named RJ35 was isolated from a rapeseed field soil, and it was identified by morphological and molecular biological methods. The myrosinase produced by strain RJ35 was purified by sequential ultrafiltration and gel filtration chromatography and its enzymatic properties were studied. Strain RJ35 was assigned to the genus Sphingobacter. The molecular mass of the myrosinase was about 100 kDa. The optimum pH and temperature of the myrosinase were 7.5 and 40 ℃, respectively. Moreover, metal ions had no significant activating effect on the myrosinase. The results of high performance liquid chromatography (HPLC) showed that this enzyme could hydrolyze radish seed extract to produce sulforaphane. Hydrolysis for 30 min under the optimum conditions resulted in a yield of sulforaphane of 5.95 mg/g (radish seed). These research results may lay an experimental foundation for the development of microbial myrosinase.