Abstract: The analysis on the 1971-2000 meteorological data showed that in the Loess Plateau of East Gansu, air temperature had an obvious increasing trend, especially in winter and spring, and the mean, maximum and minimum temperature increased simultaneously. The maximum temperature got its peak at the turn of seasons, while the minimum temperature always presented increasing trend, with larger increment than that of the maximum temperature. Both the minimum and maximum temperatures were increased obviously in December. Under the effects of climate warming, evaporation increased notably, and the beginning of boundary temperature was advanced while its ending was delayed. The accumulated temperature of ≥0 ℃ and ≥10℃ increased, frost-free period lengthened, and soil moisture in spring and autumn reduced. No significant variation was observed in precipitation, bright sunshine duration, solar radiation, and air relative humidity. The variation of these elements caused by climate warming had both advantages and disadvantages to agricultural production. To improve agricultural economic benefits, agricultural administrative departments should adjust and optimize farming systems in time, go after profits and avoid disadvantages, and make full use of climate resources, according to the variation characters of local climate.

Key words: Cd²⁺, Pollution of heavy metal, Alternanthera philoxeroides, Antioxidant enzyme systems, Ultrastructure