内生真菌对营养亏缺下金钗石斛幼苗生长的影响

Effects of Endophytic Fungi on the Seedling Growth Characteristics of Dendrobium nobile under Nutritional Deficiency

【目的】探讨营养亏缺下内生真菌对金钗石斛组培苗生长的影响。【方法】金钗石斛组培苗移栽时在其根部分别添加内生真菌37号、117号、120号菌株及无菌水,然后再分别在1倍、1/2倍、1/4倍和1/8倍Hoagland营养液中培养30 d,通过测定植株生长特征、生理特性等指标来判定内生真菌在不同稀释倍数营养液中的作用效果。【结果】随着Hoagland营养液逐渐变稀,各内生真菌处理组的植株干重、叶绿素SPAD值、总生物碱、水溶性多糖和氮磷钾含量增加量显著高于对照组,根长和根茎比增加量显著小于对照组。3株内生真菌处理间各种指标变化并不完全相同,37号菌株在增加干重和总生物碱含量上作用最为显著,而120号菌株在控制根长和根茎比、提高水溶性多糖含量、增加对磷和钾元素的吸收上效果更为突出,117号菌株在提高叶绿素SPAD值和促进植株吸收氮元素上作用最为明显。【结论】3株菌株均能促进金钗石斛幼苗在营养亏缺下的生长,但作用效果各不相同,生产中混合使用效果更佳。

[Purpose]The effects of No.37,117 and 120 endophytic fungi strains isolated from Dendrobium nobile on the growth and physiological characteristics of D.nobile under nutritional deficiency condition were detected in this study.[Method]The endophytic fungi strains No.37,117,120 and distilled water were sprayed on the root of tissue culture regenerated seedlings of D.nobile.Each group was cultivated for 30 days with 1,1/2,1/4 and 1/8 of Hoagland nutrient solution,respectively.After 30 days,the effect of endophytic fungi inoculation was determined by measuring the plant growth and physiological characteristics.[Results]With the decrease of Hoagland solution concentration,the endophyte treatment groups were significantly higher than the control group(treated with distilled water)in dry weight,chlorophyll SPAD value,total alkaloids,water-soluble polysaccharides and NPK content.The root length and root shoot ratio increased less than the control group.The changes of various indexes were not completely the same between the three endophytic fungi strain treatments.Strain No.37 treatment showed the most significant ability in dry weight and total alkaloid content increase.Strain No.120 was more prominent in controlling root length and root shoot ratio,promoting water-soluble polysaccharide content and phosphorus and potassium absorption.Strain No.117 showed the most obvious effect on increasing chlorophyll SPAD value and promoting nitrogen absorption.[Conclusion]All of these three endophytic fungi strains can promote the growth of D.nobile seedlings under nutrient deficit condition,but they showed different types of effect.Therefore,the combination use of these three endophytic fungi will produce better results.