施氮量和氮磷配比对云烟87生长及碳代谢的影响OA

To explore the nutrient synergistic fertilization model for enhancing the accumulation of sweet-related substances in tobacco leaves,a randomized block field experiment was conducted using Yunyan 87 as the material at the Tobacco Production Technology Center in Yongzhou City,Hunan Province,in 2024.Two experimental factors were set up:nitrogen application level(conventional nitrogen application and increased nitrogen application)and nitrogen-phosphorus ratio(N∶P2 O5=1∶0.7,1∶1,and 1∶1.3),resulting in a total of six treatments.The growth,photosynthetic characteristics,and key enzyme activities involved in carbohydrate synthesis during carbon metabolism were compared and analyzed under different treatments.The results showed that with the increase in phosphorus application ratio,the plant height,stem girth,and the length and width of the largest lower leaves at the rosette and vigorous growth stages significantly increased,and the number of leaves and the length and width of the largest middle leaves at the maturity stage also significantly increased.Under the same nitrogen application level,increasing phosphorus fertilizer significantly enhanced the transpiration rate,photosynthetic rate,and stomatal conductance of tobacco leaves throughout the growth period.Under the same nitrogen-phosphorus ratio,increasing nitrogen application had no significant effect on agronomic traits and photosynthesis across the whole growth period.In terms of sugar synthesis,sucrose phosphate synthase activity in tobacco leaves significantly increased with the increase in phosphorus application ratio and nitrogen application level,while adenosine diphosphate glucose pyrophosphorylase activity first increased and then decreased with the increase in phosphorus application ratio.The increase in phosphorus application ratio was conducive to the accumulation of reducing sugars in mature tobacco leaves,whereas increased nitrogen application significantly reduced the total sugar content in tobacco leaves.Comprehensive analysis indicates that under conventional nitrogen application conditions in the tobacco-rice rotation area of southern Hunan,controlling the N∶P2 O5 ratio at 1∶1.3 can effectively optimize the agronomic traits of tobacco leaves,enhance photosynthetic and carbon metabolic,synergistically promote the accumulation of reducing sugars,and improve tobacco quality.