不同苗龄毛棉杜鹃幼苗与杜鹃类菌根真菌的共生效应

Symbiotic effects between Rhododendron moulmainense seedlings of different ages and ericoid mycorrhizal fungi

【目的】分析接种杜鹃类真菌对不同苗龄毛棉杜鹃(Rhododendron moulmainense)的共生效应,为毛棉杜鹃菌根化育苗提供理论依据。【方法】设大苗龄(b,1.5年生)、中苗龄(m,1.0年生)和小苗龄(s,0.5年生)3种毛棉杜鹃实生苗苗龄,通过回接试验,测定分析接种福廷瓶头霉菌(Phialocephala fortinii,Pf)和聚多曲霉菌(Aspergillus sydowii,As)的毛棉杜鹃幼苗生长、根系形态和叶绿素荧光参数等指标。【结果】与不接种任何真菌对照(CK)相比,接种Pf和As两种菌种对大、中苗龄毛棉杜鹃幼苗生长均有促进作用,接种As对大、中苗龄地上或地下部的促进作用均小于接种Pf。其中,接种Pf对中苗龄毛棉杜鹃幼苗地上部生长的促进作用最明显,对大苗龄毛棉杜鹃幼苗地上部生长的促进作用次之;接种Pf对大苗龄毛棉杜鹃幼苗根系生长的促进作用最明显,对中苗龄毛棉杜鹃幼苗根系生长的促进作用次之;接种Pf和As对小苗龄毛棉杜鹃幼苗地上部及根系生长表现抑制作用。3个苗龄接菌组毛棉杜鹃幼苗的比叶面积均小于CK组;接菌组的实际光量子产量(YII)、非光化学淬灭(NPQ)和表观光合电子传递速率(ETR)均显著高于CK组(P<0.05),各苗龄相对于CK组提高倍数排序为小苗龄>中苗龄>大苗龄。总体上,接种Pf对毛棉杜鹃幼苗光合能力的提高作用优于接种As。【结论】接种Pf和As可与大、中和小苗龄毛棉杜鹃幼苗形成良好的共生体,其中,大苗龄和中苗龄接种Pf和As后可提高其光合能力,促进植株和根系生长,尤其以接种Pf的促进作用更明显,小苗龄接种Pf和As后生长受到一定的抑制。因此,毛棉杜鹃的菌根化育苗以选择中苗龄接种Pf效果更佳。

【Objective】Symbiotic effects of ericoid mycorrhizal fungi inoculation on Rhododendron moulmainense were analyzed to provide reference for growing seedling with mycorrhizae.【Method】Big seedlings(b,1.5years),middle seedlings(m,1.0year)and small seedlings(s,0.5year)of R.moulmainense were set.Arti-ficial inoculation experiment was applied to analyze effects of Phialocephala fortinii(Pf)and Aspergillus sydowii(As)inoculation on seedling growth,root system characteristics and chlorophyll fluorescence parameters of R.moulmainense.【Result】Seedling growth of big and middle seedlings inoculated with Pf and As were promoted compared with non-inoculated seedlings(CK).The promotion effects of As on above ground and underground parts of big and middle seedlings were smaller than As.Pf inoculation had the optimal promotion effects on above ground part of middle seedlings,and followed by the effects on above ground part of big seedlings.Root growth improvement of big seedlings inoculated with Pf was the most obvious,that of middle seedlings was the second.However,Pf and As inoculation presented inhibition effects on above ground part and root of small seedlings.Specific leaf areas of inoculated seedlings were lower than that of CK.Yield of light quantum(YII),nonphotochemical quenching(NPQ),electron transferring rate(ETR)of inoculated seedlings were significantly higher than those of CK(P<0.05),those of CK(P<0.05),and their multiples of ascension compared with CK were:small seedlings>middle seedlings>big seedlings.As a whole,photosynthetic ability of seedlings inoculated with Pf was higher than those inoculated with As.【Conclusion】After inoculation,big,middle and small seedlings can form good symbiosis with Pf and As.Photosynthetic ability,plant and root growth of big and middle seedlings inoculated with Pf and As are promoted,and the effects of Pf are more obvious.But growth of small seedlings inoculated with Pf and As is inhibited.Therefore,Pf inoculation applying to middle seedlings is recommended for growing seedling with mycorrhizae.