盐胁迫下丛枝菌根真菌接种和虎尾草伴生对羊草生长和生理特性的影响

Effects of Arbuscular Mycorrhizal Fungi Inoculation and Association with Chloris virgata on Growth and Physiological Characteristics of Leymus chinensis under Salt Stress

松嫩平原盐渍化土壤中广泛分布的丛枝菌根真菌(Arbuscular mycorrhizal fungi,AMF)能够与该地区的优势草种——羊草(Leymus chinensis)良好共生并提高其盐碱耐性。同时,虎尾草(Chloris virgata)作为羊草的自然伴生种,可能通过种间互作影响羊草生长,但有关虎尾草伴生以及虎尾草与AMF共同作用影响羊草生长的机制尚未见报道。本研究以松嫩盐碱草地羊草根围的AMF群落为接菌剂,虎尾草为伴生种,开展盆栽控制试验,探究盐胁迫下AMF、虎尾草以及二者相互作用对土著植物羊草生长的影响。结果表明:(1)盐胁迫显著抑制羊草生长,但能够促进AMF对羊草根系的侵染。(2)盐胁迫下,接种AMF能够提高球囊霉素相关土壤蛋白含量、羊草地上生物量和过氧化物酶活性,并促进叶片生长和叶绿素合成;而虎尾草伴生可以显著提高盐胁迫下羊草幼苗的叶绿素含量、过氧化氢酶活性和渗透调节物质浓度;AMF与虎尾草伴生共同作用有效缓解了羊草植株损伤,其根系侵染、球囊霉素相关土壤蛋白含量、叶长、地上生物量以及过氧化氢酶活性均得到提高,同时,该处理的丙二醛含量最低。(3)在无盐胁迫处理组中,除球囊霉素相关土壤蛋白含量、过氧化氢酶活性以及可溶性糖含量外,AMF接种、虎尾草伴生和二者交互处理组的羊草植株生长和生理指标数值均低于对照组。

Arbuscular mycorrhizal fungi(AMF)widely distributed in salinized soil of Songnen Plain were able to symbiosis well with Leymus chinensis,the dominant grass species in the area,and improved its saline-alkali tolerance.Chloris virgata,a natural companion species of L.chinensis,may affect the growth of L.chinensis through interspecies interaction.However,the mechanisms underlying the association of C.virgata and the combined effects of C.virgata and AMF on L.chinensis growth had not been reported.In this study,the AMF community in the rhizosphere of L.chinensis in Songnen saline-alkali grassland was used as inoculation,and C.virgata as a companion species to establish a pot control experiment to explore the effects of AMF,C.virgata and their interaction on the growth of indigenous plant L.chinensis under salt stress.The results were as follows:(1)Salt stress significantly inhibited the growth of L.chinensis,but could promote the invasion of AMF on the root system of L.chinensis.(2)Under salt stress,inoculation with AMF could increase the glomalin-related soil protein(GRSP)content,aboveground biomass and peroxidase activity,and promote leaf growth and chlorophyll synthesis.As a companion species,C.virgata could significantly increase the chlorophyll content,catalase activity,and osmoregulatory substance concentration of L.chinensis seedlings under salt stress.The combined effect of AMF and its companion species effectively alleviated plant damage,resulting in increased root infection,GRSP content,leaf length of L.chinensis,aboveground biomass,and catalase activity.Meanwhile the malondialdehyde content of the treatment was the lowest.(3)In the salt free stress treatment group,except for the GRSP content,catalase activity,and soluble sugar concentration,the plant growth and physiological indices of AMF inoculation,C.virgata accompanying,and their interaction treatment groups were lower than those of the control group.