混合接菌及营养元素对杜鹃苗生理生化特性的影响

Effects of Fungal Addition and Fertilizer Usage on Physiology and Biochemistry of Rhododendron simsii Seedlings

【目的】探索杜鹃苗对不同混合接菌组合及营养元素的生理响应机制。【方法】以2年生杜鹃(Rhododendron simsii)苗为研究对象,采用J1(杜鹃花类菌根真菌混合接菌)、J2(杜鹃花类菌根真菌和马尾松外生菌混合接菌)、J3(不接菌,对照)3种接菌组合与不同氮磷钾施肥水平,研究菌根真菌与氮磷钾肥对杜鹃苗生理生化特性的影响,测定杜鹃幼苗生物量、叶绿素含量(chl)、超氧化物歧化酶(SOD)活性、过氧化物酶(POD)活性、过氧化氢酶(CAT)活性、丙二醛(MDA)含量、可溶性蛋白(SP)含量、可溶性糖(SS)含量、生长素(IAA)含量、细胞分裂素(ZR)含量、赤霉素(GA3)和脱落酸(ABA)含量的变化情况,并采用主成分分析法对各指标进行筛选。【结果】混合接菌和施肥处理都能提高杜鹃叶片的叶绿素a含量、叶绿素b含量、叶绿素总含量、SOD活性、POD活性、CAT活性、SP含量、IAA含量、ZR含量和GA3含量,降低杜鹃幼苗的MDA含量,同时接菌处理较不接菌处理只需要施正常氮磷钾肥量的1/4~1/2水平即可最大程度增强杜鹃苗的生理水平,特别是接J2处理。菌根共生体可能是通过促进养分吸收,增强光合作用能力,刺激激素合成,降低膜脂过氧化程度,提高保护酶活性,增强杜鹃苗的抗逆能力,促进杜鹃苗生长。根据相关性分析可得,各指标均具有相关性。【结论】生理生化指标总体表现为接菌处理优于不接菌处理,J2处理施养分1/2水平(即施用尿素1.1 g·株^-1、钙镁磷1 g·株^-1、氯化钾0.7 g·株^-1)对杜鹃苗生长及生理生化指标的影响最为明显,叶绿素含量(Chl)、超氧化物歧化酶活性(SOD)、可溶性蛋白(SP)、生长素(IAA)、赤霉素(GA3)可以作为反映杜鹃苗生长评价的主要指标。

【Objective】Responses of azalea(Rhododendron simsii)seedlings cultivated under the applications of fungi and NPK fertilizer were studied.【Method】Various fungal additions and NPK fertilizations were applied in cultivating 2-year-old azalea seedlings.The fungal treatments included Rhododendron mycorrhizae(J1),mixture of R.mycorrhizae and exophytic Pinus massoniana(J2),and blank control(J3).The fertilization was varied on the rate of application.Physiology and biochemistry of the azalea seedlings grown under the treatments were determined.Seedling biomass,chlorophyll(Chl)content,and activities of superoxide dismutase(SOD),peroxidase(POD),and catalase(CAT),as well as contents of malondialdehyde(MDA),soluble protein(SP),soluble sugar(SS),auxin(IAA),cytokinin(ZR),gibberellic acid(GA3),and abscisic acid(ABA)of the plants were measured and subjected to a principal component analysis.【Results】The fungal additions increased the contents of Chla,Chlb,total Chl,SP,IAA,ZR,and GA3 as well as the activities of SOD,POD,and CAT,but reduced the MDA content in the seedlings.The addition,especially J2 treatment,allowed the seedlings to performed well physiologically with merely 1/4 to 1/2 of the normally applied amount of NPK fertilizer.It was speculated that the mycorrhizal symbiosis as observed might be the result of the improved nutrient absorption,photosynthesis,hormone synthesis,protective enzyme activity,stress resistance,and growth of,as well as the reduced membrane lipid peroxidation in the plants.It appeared that all indicators selected for this study were correlated.【Conclusion】The overall physiological and biochemical indicators on the azalea seedlings cultivated with the fungal applications were better than those of control.In particular,the treatment of J2 not only reduced the NPK fertilization by half(i.e.,urea 1.1 g·plant^-1,CaMgP 1 g·plant^-1,and KCl 0.7 g KCl·pllant^-1)but also elevated the levels of Chl,SOD,SP,IAA,and GA3 on the azalea seedlings.