Effects of Spraying Period and Concentration of Naphthylacetic Acid on Carbon Metabolite Contents and Key Enzyme Activities in Upper Leaves of Flue-Cured Tobacco
Long Shangyuan
Huang Renjie
Zhang Yu
Xiong Jing
Wu Xueqiao
Gao Junyi
Li Pengzhi
Gao Huanye
Abstract：In order to explore the metabolic mechanism of spraying exogenous naphthylacetic acid(NAA)on the formation of availability in the upper leaves of flue-cured tobacco,Yunyan 87 was used as test material in this study.A two-factor randomized block trial with 12 treatments of NAA spraying period(on the topping day,at 15 days after topping,at 30 days after topping)and spraying concentration(0,10,30,50 mg/L)was designed,and their effects on content of carbon metabolites,key enzymes activities and related gene expressions in the upper leaves of flue-cured tobacco were studied.The results showed that spraying high concentration of NAA on the topping day and spraying low concentration of NAA at 15 days after topping could promote the accumulation of starch in the upper leaves,and spraying NAA at 15 days after topping could pro-mote the accumulation of total sugar and reducing sugar,while spraying NAA at 30 days after topping reduced the content of total sugar and reducing sugar.In terms of key enzymes activities,the sucrose synthetase(SS)and sucrose phosphate synthase(SPS)activities were the highest when NAA was sprayed with medium high concentration at 15 days after topping,but the invertase(INV)activity of the upper leaves were inhibited by spraying NAA.In terms of the expression levels of key enzyme genes,spraying NAA reduced the expression levels of SS gene NtSS and INV gene NtINV.In conclusion,under the ecological conditions in Weining tobacco area,Bijie City,Guizhou Province,spraying 30 mg/L NAA at 15 days after topping was the most beneficial to improve the key enzymes activities of carbon metabolism in the upper leaves of Yunyan 87,increas the expres-sion of enzyme genes,and coordinate the carbon metabolism process during the maturity of upper leaves of to-bacco.
Keywords：Flue-cured tobaccoNaphthylacetic acid(NAA)Upper leavesCarbon metabolism
Publication Date：2025-12-30
Online Publishing Date：2026-05-22(First online date of this platform, not the publication date of the document)
Pages：6( 48-53 )