接种不同根瘤菌对花榈木幼苗光合生理的影响及促生效应

为筛选促生效果好的花榈木Ormosia henryi根瘤菌菌株，建立良好的共生固氮体系，从贵州、浙江、安徽、福建、江西等不同地区采集花榈木根瘤并进行分离鉴定，将通过16S rDNA序列分析及回接验证的20株纯化菌株接种到1年生盆栽无菌花榈木幼苗上，并测定接种后花榈木幼苗光合速率、蒸腾速率、叶绿素荧光参数、生长指标及结瘤指标。研究结果表明:20个菌株接种后结瘤率均在90%以上，其中7号菌株结瘤率、结瘤数、根瘤质量均最高。接种根瘤菌能显著（P < 0.05）提高花榈木幼苗光合速率、蒸腾速率以及叶绿素荧光参数，促进花榈木幼苗的地上地下部分生长及总生物量积累，且接种不同菌株的促生效果差异显著（P < 0.05）。与对照相比，接种根瘤菌的花榈木幼苗光合速率、蒸腾速率、实际光合量子产量分别提高41.6%~197.4%，3.2%~512.9%和4.8%~95.2%；总根表面积、根平均直径、根尖数分别增加3.4%~866.1%，6.7%~193.3%和0.5%~92.1%；苗高生长量、地径生长量和生物量分别增加6.3%~273.8%，10.7%~185.7%和37.9%~310.3%。隶属函数综合评价结果表明:对花榈木幼苗光合生理和生长有显著促进作用的前5个菌株号为15号、16号、7号、18号、17号，可作为花榈木幼苗接种的优良菌株。

Growth of Ormosia henryi seedlings and photosynthetic and physiological characteristics with rhizobia inoculation

To screen the growth-promoting strains of rhizobia for Ormosia henryi and to establish a good symbiotic nitrogen-fixing system, root nodules of O. henryi collected from Guizhou, Zhejiang, Anhui, Fujian, and Jiangxi Provinces were isolated and identified. Using randomized block design, 20 strains of rhizobia that passed reinoculation and 16SrDNA sequence analysis were inoculated into one-year-old aseptic potted O. henryi seedlings followed by measurement of the photosynthetic rate, transpiration rate, chlorophyll fluorescence parameters, growth indexes, and nodulation indexes. Results showed that the nodulation rates of the 20 strains were above 90.0%, the nodule number and nodule weight of strain No. 7 was the highest. Compared to the control which was not been inoculated, inoculation rhizobium significantly (P < 0.05) increased photosynthetic rate, transpiration rate and chlorophyll fluorescence parameters of O. henryi seedlings. Rhizobium also promoted the growth of above ground and underground parts as well as accumulation of total biomass. Seedlings with different rhizobium strains increased the photosynthetic rate (41.6%-197.4%), transpiration rate (3.2%-512.9%), actual photosynthetic quantum yield (4.8%-95.2%), total root surface area (3.4%-866.1%), average root diameter (6.7%-193.3%), root number (0.5%-92.1%), seedling height growth (6.3%-273.8%), diameter growth (10.7%-185.7%), and biomass (37.9%-310.3%). The comprehensive evaluation showed that the best five strains for promoting growth of O. henryi seedlings were No. 15, 16, 7, 18, and 17, and these could be used as excellent strains for inoculation of O. henryi seedlings.