作　　者： ; ; ;

机构地区： 韶关学院英东农业科学与工程学院

出　　处： 《热带作物学报》 2019年第9期1677-1684,共8页

摘　　要： 采用盆栽砂培试验方法研究了不同钾水平供应下烤烟生长及其对吸收硝态氮的动力学参数特征的影响。主要结论如下:与低钾(K1)、高钾(K3)处理相比,烤烟在中钾(K2)处理时地上部、根系鲜、干重均增加;随钾浓度增加,钾由根系向地上部运输比例增加,而烤烟生育前期净光合速率无显著性差异,但后期净光合速率显著增加;中钾(K2)水平增加根系总根长、总表面积、平均直径和总体积,而高钾(K3)水平反而有抑制作用。不同供钾水平预处理后,烤烟对NO3^--N吸收符合离子吸收动力学模型,其吸收动力学参数表现为钾水平预处理浓度增加后,Vmax增大,Km值增加,但增加的幅度不一致。与低钾(K1)预处理相比,高钾(K3)预处理降低烤烟根系高亲和力系统对NO3^--N的吸收速率,而中钾(K2)处理提高烤烟根系高亲和力系统的NO3^--N的吸收速率,表明烤烟根系吸收NO3?-N的高亲和力系统受钾水平调控,适宜钾浓度预处理提高烤烟根系对低浓度NO3?-N的吸收。对低亲和系统来说,与低钾预处理相比,中钾(K2)和高钾(K3)预处理均提高了烤烟根系低亲和力系统对NO3?-N吸收,表明长期高钾环境生长下的烤烟,根系对硝态氮吸收的低亲和力系统影响较小,而长期低钾环境生长下的烤烟,根系对硝态氮吸收低亲和力系统有抑制作用。 In the present study,the growth and the absorption dynamic parameter of NO3^--N in flue-cured tobacco, which was pretreated in different concentrations of KCl,were investigated with sand culture test. The results showed that compared with low (K1) and high K (K3) treatments,the fresh and dry weight of the shoot and root of the flue-cured tobacco increased under medium potassium (K2) treatments. With the increase of K concentration,the proportion of potassium transported from roots to shoots increased,while the net photosynthetic rate of the flue-cured tobacco had no significant difference in the early growth stage,but increased significantly in the late growth stage. Compared with low (K1),medium K (K2) level increased total root length,total surface area,average diameter and total volume,while high potassium (K3) level inhibited it;the uptake of NO3^--N of the flue-cured tobacco was in accordance with Michelis- Menten equation pretreated with different concentrations of KCl,and the uptake kinetics parameters,Vmax and Km were enhanced with the K pretreatment concentration increased,but the increase range was not consistent. For the high-affinity system,compared with low K (K1) pretreatment,high K (K3) pretreatment decreased the uptake rate of NO3^--N,while medium K (K2) pretreatment increased the uptake rate of NO3^--N,which indicated that the high affinity system of NO3^--N uptake by the flue-cured tobacco was regulated by K level,and appropriate K level pretreatment increased the uptake rate of low concentration NO3^--N. For the low-affinity system,compared with low K pretreatment, medium K (K2) and high K (K3) pretreatment could significantly increase the absorption of NO3^--N,which indicated that the root uptake of NO3^--N of the low-affinity system was less affected by long-term high K environment,while was restrained at long period of low K environment.

关 键 词： 烤烟 钾预处理 硝态氮吸收 动力学特征 亲和力系统

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