Se accumulation in flue-cured tobacco related to soil and climate

11 counties in 7 provinces were selected from south and north tobacco growing areas in China to investigate the contents of Se in tobacco in relation to environments under a same cultivation model.The results showed that Se in tobacco plants were changed in the sequence: roots > leaves≈shoots(flowers) > stems.Highest Se was detected in upper leaves,while lowest showed in lower ones.During the growing period,the contents of Se in leaves changed little if any, but the amount of Se accumulation went up with a "S" curve and the accumulation rate of Se appeared as a single peak curve.Even though mean concentrations of Se were similar in tobacco leaves produced in north and south China,the variation coefficients of Se concentrations in tobacco leaves were quite large,indicating the significant influences of environments on them.In regarding Se metrological factors,there was a negative correlation between Se contents in tobacco leaves and rainfall(or relative humidity),but a positive correlation with mean air temperatures(or soil temperatures at 10 cm).Furthermore,a positive correlation was found between the contents of Se in tobacco leaves with soil pH and total Se,whilst a negative correlation with available phosphorus and organic matter in soil.