铝对马尾松菌根苗生长及营养元素吸收的影响

Effects of Aluminum on growth and nutrient element absorption of mycorrhizal Pinus massoniana seedlings

以接种褐环乳牛肝菌和未接种的马尾松幼苗为试验材料,采用水培法研究不同浓度铝(Al^3+)处理(0、0.2、0.4、0.8和1.2 mmol·L^-1)对菌根化和非菌根化马尾松幼苗生长、营养元素吸收的影响,揭示菌根化马尾松苗木对Al^3+的适应机制,为减轻马尾松苗木铝毒害现象提供理论和技术依据。结果表明,在相同浓度Al^3+胁迫下,接种褐环乳牛肝菌的马尾松幼苗苗高、生物量、根系形态以及对氮(N)、磷(P)、钾(K)的吸收能力均优于不接种的马尾松苗。马尾松幼苗苗高、干物质量积累以及根系生长随着Al^3+浓度的增大均呈现先升后降再升的趋势,随着Al^3+浓度的逐渐增大,马尾松幼苗根、茎、叶中的N、P、K含量呈现出低促高抑的趋势,根、茎、叶中Al^3+含量的分配为根>茎>叶。Al^3+胁迫下,接种褐环乳牛肝菌的马尾松幼苗,通过改变马尾松幼苗根系结构,促进了幼苗的生长,特别是根系的生长,以及对N、P、K等营养元素的吸收,抑制了根系吸收Al^3+,提高了马尾松幼苗的耐铝能力。

This study aims to investigate the adaptation mechanism of mycorrhizal Pinus massoniana seedlings to aluminum(Al^3+),and to provide a theoretical and technical basis for alleviating aluminum toxicity in P.massoniana seedlings.The effect of mycorrhiza on growth and nutrient absorption in P.massoniana seedlings was investigated by comparing uninoculated seedlings(control)with seedlings inoculated with Suillus luteus(SL),subjected to one of five different Al^3+concentrations(0,0.2,0.4,0.8 and 1.2 mmol·L^-1)grown in a hydroponic system.Results showed inoculated seedlings,when compared to uninoculated seedlings grown in equivalent Al^3+concentrations,demonstrated increased growth in plant height,biomass,and root morphology,as well as an increased capacity to absorb N,P and K.For both inoculated and uninoculated P.massoniana seedlings;the height of the plant,accumulation of dry matter mass,and root growth,showed a fluctuating trend of first rising,then falling,then further rising with increased concentrations of Al^3+.In addition,for both inoculated and uninoculated seedlings,the gradual increase of Al^3+concentration of N,P and K content in roots,stems,and leaves demonstrated a tendency toward low concentration thus promoting high concentration inhibition(the order of Al^3+content measured in three plant organs,ordered from high to low,was root>stem>leaf).The results of our study suggest that P.massoniana seedlings inoculated with SL under Al^3+stress appear to be able to promote the absorption of nutrients(such as N,P and K)and inhibit absorption of Al^3+in mycorrhizal P.massoniana seedlings by changing the structure of the root.