EFFECT OF SULPHATE RATES SUPPLIED ON SULPHUR METABOLISM AND N, P AND Cl ABSORPTION IN TOBACCO

The effects of sulphate rates supplied on the growth, development and sulphur absorption, metabolism of tobacco ( Nicotiana tobacum var. NC89) were studied in this paper. The results showed that sulfur deficiency retarded tobacco growth, delayed flowering emergence, and got much less plant height, stem diameter, leaf length, leaf width, leaf area and dry weight, etc. than those of normal sulfur nutrition plants. Tobacco plants could suffer very higher sulfate rate applied although the stem diameter and leaf widths were adversely affected. The total sulfur contents increased greatly with the increment of sulfur supply, up to 14 10g/kg under the highest sulfur rate tested. The inorganic sulfur accounted for a large proportion of the total sulfur increase and sulfur in amino acids only for a little fraction of it. Sulphur in protein held the line as the increase of sulfur supply. The correlation analysis showed that the inorganic sulfur contents positively correlated very significantly with total sulfur contents(r=0.9713 ** ). Sulfur and nitrogen promoted and inhibited each other. Both sulfur deficiency and sulfur surplus inhibited the absorption of phosphorus, but the contents of chloride declined straightly with the increase of sulfur supply.