金银花容器苗对干旱胁迫下接种根际促生细菌的生理响应  

Physiological responses of Lonicera japonica container seedlings to plant growthpromoting rhizobacteria inoculation under drought stress

作　　者：刘方春[1] 马海林[1] 杜振宇[1] 马丙尧[1] 井大炜[2] 邢尚军[1] 

机构地区：[1]山东省林业科学研究院,山东省森林植被生态修复工程技术研究中心,济南250014 [2]德州学院,德州253023

出　　处：《生态学报》2015年第21期7003-7010,共8页Acta Ecologica Sinica

基　　金：山东省科技发展计划专项资助(2010GSF10621,2014GNC113006)

摘　　要：在盆栽试验条件下,以金银花容器苗为试材,研究了不同干旱强度下接种蜡样芽孢杆菌(Bacillus cereus)L90对植物生理特征的影响。结果表明:随着干旱胁迫强度的增加,金银花容器苗的光合速率和气孔导度逐渐降低;而干旱环境下接种L90可显著提高气孔导度,缓解干旱胁迫对净光合速率的抑制;且干旱强度增加,缓解效果增强。接种B.cereus L90可显著抑制干旱胁迫下金银花容器苗PSⅡ最大光化学效率、实际光化学效率和光化学猝灭系数的降低,抑制非光化学猝灭系数的升高。虽然L90并没有提高对照处理中光合色素的绝对含量,但可显著抑制干旱环境下金银花叶片中光合色素的分解。干旱显著降低了金银花叶片中细胞分裂素含量,增加了脱落酸(ABA)的含量;在干旱胁迫下,接种L90可显著提高叶片中细胞分裂素的含量,并可促使根部产生的ABA运输到叶片中。干旱胁迫程度较轻时,L90对金银花容器苗的相对含水量和相对电导率影响不显著;而在重度干旱时,同对照相比,干旱及接种L90处理的相对含水量分别降低20.56%和10.21%,相对电导率分别提高31.42%和16.08%,接种L90处理的变化幅度明显较小。因此,干旱生境下接种B.cereus L90,可增加叶片中细胞分裂素含量,抑制光合色素的分解及光合能力的下降,提高金银花容器苗在干旱环境中的适应能力。Plant growth-promoting rhizobacteria （PGPR） are rhizosphere inhabitants that promote plant growth and suppress diseases. One of the proposed mechanisms through which PGPR enhance plant growth is the production of plant growth regulators, especially cytokinin. However, little information is available about the effects of cytokinin-produeing PGPR inoculation on the drought stress response. Soil water availability is a crucial determining factor of plant yield, because drought stress inhibits stem elongation, leaf expansion, and stomatal movement. Therefore, a strain of rhizobaeteria with a high rate of eytokinin production, Bacillus cereus L90, was selected for use in this investigation. The bacteria were obtained from the rhizosphere of a walnut tree, where water is limited and frequent dry periods occur. Serial dilution and a bioassay for the detection of cytokinin production were both used to isolate and screen the bacterial strain from the soil sample. This study investigated how PGPR affects the physiological characteristics of Lonicera japonica Thunb. under different drought stress treatments （light, moderate, severe, and a control）. The combined effects of B. cereus L90 inoculation and various levels of drought stress on the photosynthetic characteristics, chlorophyll fluorescence parameters, photosynthetic pigment, cytokinin and ABA（ abscisic acid） concentrations, relative water content, and relative electrolyte leakage were studied using the pot method. The results showed that the net photosynthetic rate and stomatal conductance decreased with increasing drought stress. However, B. cereus Lg0 inoculation was associated with an increase in stomatal conductance and net photosynthetic rate in plants under drought stress. B. cereus Lg0 inoculation reduced the negative impact of drought stress on the maximum photochemical efficiency of PS I1 , the actual photochemical efficiency of PS 11 , and the photochemical quenching coefficient. B. cereus L90 inoculation also prevented the non-photochemical que

关 键 词：干旱胁迫 金银花 植物根际促生细菌 蜡样芽孢杆菌 生理响应 

分 类 号：Q945.78[生物学—植物学]