不同形态氮素与不同镁浓度供应对烤烟光合荧光特性的影响

Effects of Different Nitrogen Forms and Different Magnesium Concentrations on Photosynthetic Fluorescence Characteristics of Flue-Cured Tobacco

为了解不同形态氮素与不同镁浓度对烤烟早期光合荧光特性及生长的影响,以翠碧一号烤烟为材料,采用水培试验方法,在温度较低、光照较弱条件下设置3种氮素处理和两个镁水平,分析不同处理烟株光合荧光特性及生长的差异。结果表明,加镁条件下铵、硝态氮各50%处理烟株的生物量、最大净光合速率(P_(max))、表观量子效率(AQY)和光系统Ⅱ(PSⅡ)与光系统Ⅰ(PSⅠ)及系统间电子传递链的整体功能活性指数(PI_(total))均最高,其中生物量相较于纯硝态氮且加镁处理提高21.7%,相较于纯铵态氮加镁处理提高96.0%;不加镁条件下全硝态氮处理P_(max)和AQY高于铵、硝态氮各50%处理且显著高于全铵态氮处理。纯硝态氮处理和铵、硝态氮各50%处理加镁后显著提高各项指标,但加镁对全氨态氮处理没有显著性影响。可见,在温度较低、光照较弱条件下,铵、硝各50%且加镁处理更有利于烤烟早期的生长发育。

In order to understand the effects of different nitrogen forms and magnesium concentrations on the photosynthetic fluorescence characteristics and growth of flue-cured tobacco at early stages,using Cuibi No.1 flue-cured tobacco as the material,three nitrogen treatments and two magnesium levels were set under low temperature and low light by a hydroponics test method,and the photosynthetic fluorescence characteristics and growth differences of different treatments were analyzed.The results showed that biomass,_(max)imum net photosynthetic rate(P_(max)),apparent quantum efficiency(AQY)and the overall functional activity index(PI_(total))of the electron transport chain between PSII and PSI systems were the highest in the treatment with 50%ammonium and 50%nitrate under the condition of magnesium application.The biomass of the treatment with 50%ammonium and 50%nitrate increased by 21.7%compared with the treatment with pure nitrate nitrogen,and increased by 96.0%compared with the treatment with pure ammonium nitrogen under the condition of magnesium application.P_(max) and AQY of the pure nitrate nitrogen treatment were higher than those of the treatment with 50%ammonium and 50%nitrate and significantly higher than those of the pure ammonium nitrogen treatment under the condition of no magnesium.The addition of magnesium to the treatment of pure nitrate and treatment with 50%ammonium and 50%nitrate significantly improved all the indexes,but had no significant effect on the treatment of pure ammonia.The results showed that under the conditions of low temperature and weak light,the treatment with 50%ammonium and 50%nitrate and magnesium application can significantly improve chloroplast pigment content,electron transport efficiency,enhance photosynthetic capacity,promote biomass accumulation,and is more conducive to the early growth and development of flue-cured tobacco.