摘要
为提高植物根际促生细菌在干旱环境下的应用效果,以Bacillus cereus DZ1为供试菌株,探讨了清水稀释和豆芽汁营养液稀释处理下其在交联聚丙烯酰胺（CLP）中的存活特征,然后通过金银花造林实验,研究了接种B.subtilis DZ1（PGPR）、施用CLP（CLP）、接种B.subtilis DZ1并混施CLP（C-P）和CLP-PGPR凝胶（CPG）对植物生长及根际环境微生物特征的影响。结果表明,同清水稀释处理相比,豆芽汁营养液稀释处理CLP中的有效活菌数量显著提高19.45%~664.05%,CLP可以作为PGPR的吸附载体。同PGPR处理相比,CPG处理根系分泌物中的氨基酸总量、有机酸总量和总糖含量分别提高37.36%、30.04%和8.18%;直接接种B.cereus DZ1对根际土壤微生物量碳影响较小,但CPG处理显著提高了微生物量碳含量,并明显增强了土壤微生物呼吸作用,其微生物呼吸速率较PGPR、CLP、C-P和CK分别高出18.02%、9.93%、8.56%和18.91%;CPG处理还降低了代谢熵,与另外4个处理相比其下降幅度分别为12.74%、7.62%、8.02%和14.02%。无论B.cereus DZ1何种接种方式均对金银花的造林成活率影响不显著,但CPG处理显著增加了植物的干物质积累量,其叶片相对含水率较C-P处理显著增加10.34%,而相对电导率降低9.70%。可见,CLP-PGPR凝胶方式更有利于接种微生物的定殖存活,可改善金银花根际土壤的微生态环境,增强植物干旱耐受性的同时促进植物生长。
Plant growth-promoting rhizobacteria （PGPR） are beneficial native soil bacteria that colonize the rhizosphere or plant roots and regulate the functional properties of agricultural systems. One of the proposed mechanisms through which PGPR enhances plant growth is the production of plant growth regulators, especially cytokinin. However, little information is available regarding cytokinin-producing PGPR inoculation on growth and water stress consistence of Lonicera japonica Thunb. seedlings. Therefore, a bacterial strain with high cytokinin production and known positive effects on plant growth was selected for use in present investigation. Cross-linked polyacrylamide is a widely studied super-absorbent polymer with segments of hydrophilic groups that can absorb and retain liquids, with the absorbed water it is difficult to remove even under pressure. In addition, because of the water absorbing properties of these macromolecules, cross-linked polyacrylamide were used in a wide range of applications in agriculture and forestry. Firstly, an inoculation experiment was conducted to determine whether cross-linked polyacrylamide could be used as carrier for PGPR by inoculating Bacillus cereus DZ1. And then, a Lonicera japonica Thumb. afforestation experiment, including five treatments, i.e. PGPR （B. subtilis DZ1 inoculation alone） , CLP （cross-linked polyacrylamide was applied alone） , C- P （B. subtilis inoculation with CLP） , CPG （gel was made of PGPR and CLP） , and CK （neither B. subtilis nor CLP was applied） was conducted. The experiment was to evaluate the effect of different ways of PGPR application on Lonicera japonica Thumb. growth and microbial characteristics in rhizosphere soils. Results indicated that compared with the diluted water treatment, the number of effective viable bacteria of bean sprout juice dilution treatment in cross-linked polyacrylamide was significantly increased by 19.45% ~ 664.05%, which meant that CLP can be used as an carrier for B. subtilis DZI. The root exudates, namely amino acids, organic acids and total sugars in CPG treated Lonicera japonica Thumb. rhizosphere soils were significantly increased by 37.36%, 30.04% and 8. 18% than those in PGPR treatment. Although B. subtilis DZ1 inoculation alone had no significant effect on microbial biomass carbon contents, the CPG treatment evidently increased microbial biomass carbon and significantly enhanced microbial respiration, showing 18.02%, 9.93%, 8.56% and 18.91% increases in microbial respiration rate over the treatments of PGPR, CLP, C - P and CK, respectively. At the same time, the metabolic quotient was reduced by the CPG treatment, demonstrating 12.74%, 7.62%, 8.02% and 14.02% decreases, respectively. Besides, the CPG treatment achieved the highest Simpson index, however the lowest Shannon and McIntosh index among all the treatments. CPG treatment had no significant effect on afforestation survival rate, it was beneficial to the shoot and root dry matter accumulation of Lonicera japonica Thumb. Compared with C - P treatment, CPG treatment increased the relative water content of Lonicera japonica Thumb. leaves by 10.34%, 9.70%. As a result, the CLP- PGPR gel whereas decreased the retative electric conductance by can alleviate the drought stress and interfere with the suppression of plant growth through regulating the micro ecological environment of Lonicera japonica Thumb. rhizosphere soil, showing a real potential to perform as a drought stress inhibitor in arid environments.
出处
《农业机械学报》
EI
CAS
CSCD
北大核心
2016年第11期163-171,共9页
Transactions of the Chinese Society for Agricultural Machinery
基金
国家自然科学基金项目(31570614)
山东省科技发展计划项目(2010GSF10621
2014GNC113006)
关键词
金银花
植物根际促生细菌
交联聚丙烯酰胺
凝胶
根际
Lonicera japonica Thunb.
plant growth-promoting rhizobacteria
cross-linked poly-acrylamide
gel
rhizosphere
