不同氮素水平下内生真菌印度梨形孢定殖对烟草生长发育及物质代谢的影响

Effects of Endophytic Fungus Piriformospora indica on Growth and Metabolism of Tobacco at Different Levels of Nitrogen Nutrition

为了明确印度梨形孢(Piriformospora indica)对烟草生长发育的影响,采用平板共培养及室内盆栽试验比较了不同氮素水平下印度梨形孢定殖对烟草叶片的光合速率、总氮、NO3-含量以及代谢产物等的影响。结果表明,印度梨形孢能够定殖于烟草根部,在不同氮素水平下均能促进烟草生长,提高烟草的光合速率。低氮素水平(4 mmol/L)下,印度梨形孢定殖的烟草叶片中总氮、NO3-含量与对照差异不显著。中、高氮素水平下(8和12 mmol/L),印度梨形孢定殖明显降低了烟叶中的总氮和NO3-含量。中氮素水平下,印度梨形孢定殖显著增加了光合代谢途径中某些产物的含量(葡萄糖、D-果糖);在高氮素水平下,印度梨形孢定殖促进了光合产物的积累与氨基酸的合成代谢。因此,印度梨形孢定殖对烟草的碳氮代谢具有调节作用。

To clarify the influences of endophytic fungus Piriformospora indica （P. indica） on the growth and development of tobacco, the effects of P. indica on the net photosynthetic rate of tobacco leaf, and metabolites, the contents of total nitrogen and nitrate in tobacco at different nitrogen nutrition levels were compared via co-culture plate experiments and indoor pot experiments. The results showed that P. indica could colonize in tobacco roots, it promoted the growth of tobacco and improve the net photosynthetic rate at various nitrogen levels. At the low nitrogen level （4 mmol/L）, the total nitrogen and NO3- contents in leaves of tobacco colonized by P. indica and the control （CK） presented no significant difference; however, at the high （12 mmol/L） and medium （8 mmol/L） nitrogen levels, they were significantly reduced in colonized tobacco. Furthermore, the results of metabolite analysis indicated that P. indica colonization increased the content of some products produced in the route of photosynthetic metabolism （such as glucose and D-fructose） at medium nitrogen level; it promoted the accumulation of photosynthetic products and synthetic metabolism of amino acid at high nitrogen level. Therefore, P. indica colonization played a role in regulating the metabolism of carbon and nitrogen in tobacco.