关键词: 烤烟, 硫, 光合特性, 氮平衡指数, 农艺性状, 生物量分配

Abstract: Tobacco planting area with medium sulphur content(27.04 mg/kg) was selected,and by controlling the amount of sulfur fertilizer application(24 kg/ha,48 kg/ha,96 kg/ha,144 kg/ ha and 192 kg/ha),we studied the effect of sulphur on physiological characteristics and growth and development characteristics in budding stage.The results showed that,when the amount of sulfur fertilizer application increased in the range of 24—144 kg/ha,there was no significant change in the photosynthetic characteristics of flue-cured tobacco leaves, however, when the sulfur fertilizer application amount exceeded 144 kg/ha, the leaf stomatal conductance, transpiration rate, water use efficiency and net photosynthetic rate all decreased significantly.When the amount of sulfur fertilizer application increased in the range of 24—96 kg/ha,the root sulphur concentration and leaf N balance index increased by 48.0% and 26.0%,but when the sulfur fertilizer application amount exceeded 96 kg/ha,both the root sulphur concentration and the leaf N balance index decreased.When the sulfur fertilizer application amount increased in the range of 24—192 kg/ ha,the sulphur concentration of upper,middle and lower leaves increased by 22.7%,25.0% and 46.2% respectively,the maximum leaf length and leaf width increased by 6.4% and 15.5% respectively,and the density of upper and middle leaves increased by 12.8% and 21.2% respectively,the biomass of stems and roots decreased by 26.3% and 20.2% respectively,and the ratio of stem to leaf decreased by 20.3%,but the ratio of aboveground and underground biomass did not change significantly.Appropriate sulfur fertilizer application amount could increase the single leaf weight of flue-cured tobacco leaves,and that of upper leaves increased significantly(by up to 23.0%),but too much sulfur fertilizer decreased the single leaf weight,and that of lower leaves decreased significantly.These results indicate that,when the soil available sulfur content is moderate,the effects of sulfur fertilizer application increase on the physiological characteristics and growth and development of flue-cured tobacco differ.Taking into account all the above indicators,the sulfur fertilizer application amount of 48—144 kg/ha is favorable for the growth and development of flue-cured tobacco,when the yield of the middle and upper tobacco leaves is higher, leaf density is moderate and the growth and development relevant characteristics are also better.The local sulfur fertilizer application amount of 144.9 kg/ha reaches the
upper limit of the optimum sulfur application rate,so the local sulfur fertilizer application amount could be reduced.

Key words: Flue-cured tobacco, Sulfur, Photosynthetic characteristics, Nitrogen balance index, Agronomic traits, Biomass allocation