接种固氮菌Klebsiella sp.120对甘蔗光合特性和主要矿质营养元素含量的影响

【目的】甘蔗是最重要的糖料和能源作物,生物量大,产量高,但大量氮肥的使用不仅增加了甘蔗的种植成本,而且对农田环境造成了污染。发挥与甘蔗联合固氮的生物固氮菌的作用,是降低甘蔗氮肥施用量的方法之一。Klebsiella sp.120是从广西种植的甘蔗体内分离到的具有固氮能力的菌株。为了探讨该菌对甘蔗的促生效应及其在甘蔗上的应用潜能,本文研究了接种该固氮菌对甘蔗光合特性及矿质元素含量的影响。【方法】采用桶栽方法,在甘蔗的分蘖期用接种菌株淋浇4个不同甘蔗品种的根际,在处理后的30 d和60 d取样分析该菌对甘蔗的光合生理和矿质营养元素含量的影响。【结果】接种菌株对4个甘蔗品种的叶绿素含量和净光合速率有一定的促进作用,但不同品种之间存在差异。处理30 d后,淋浇固氮菌处理的甘蔗品种ROC22的叶绿素含量明显提高,比对照增加23%。另外3个甘蔗品种(B8、GT21和GT28)处理组的叶绿素含量均有一定的提高,但与对照相比差异不显著。处理30 d后,只有ROC22和B8品种的净光合速率高于对照,且ROC22品种处理与对照间的差异达到了显著水平。处理60 d后,4个甘蔗品种的净光合速率均高于处理30 d,而且各品种接种处理均高于对照,其中以对ROC22和GT21的促进效果最为明显,达到了显著水平。接种处理对不同甘蔗品种的营养元素含量影响不同,接种处理对4个甘蔗品种叶片中的氮元素含量有促进作用,其中对ROC22的促进效果最为明显,接种处理比对照增加59.8%。接种固氮菌对甘蔗叶片磷和钾元素含量的影响不明显。接种固氮菌对4个甘蔗品种叶片的铁、锰元素含量的影响不明显;ROC22叶片中的锌含量及ROC22和B8叶片中的铜含量接种处理与对照相比显著提高。【结论】接种Klebsiella sp.120固氮菌对甘蔗光合特性及矿质元素含量的影响与甘蔗品种有关,其中对ROC22品种的促生效果最为明显。研究结果可为固氮菌株Klebsiella sp.120在甘蔗上的进一步应用提供参考依据。

Effects of inoculating nitrogen fixing bacteria Klebsiella sp.120on photosynthetic characteristics and mineral nutrient contents of sugarcane

【Objectives】 Sugarcane (Saccharum officinarum L.) isan important sugar and energy crop with high biomass and high productivity. However, application of large amount chemical nitrogen fertilizer in sugarcane is very common in China, which not only increases the production cost, but also causes environmental pollution.A possible method of reducing sugarcane nitrogen fertilization is inoculation of nitrogen fixation bacteria. The nitrogen fixing bacteria (NFB) strain Klebsiella sp.120 was isolated from surface-sterilized roots of sugarcane cultivar ROC22.Its effect on photosynthetic characteristics and mineral nutrient accumulation in sugarcane was investigated.【Methods】 Four sugarcane cultivars were planted in pots. The strain Klebsiella sp.120 was inoculated to the plants by root watering at the tillering stage. Effects of the inoculation on photosynthetic characteristics and mineral nutrient accumulation of the four cultivars were studied after the treatment of 30 and 60 days, respectively.【Results】 The results show that the photosynthetic rates and chlorophyll contents of different cultivars are affected differently by the inoculation with Klebsiella sp.120.After 30 days inoculation increases signiticantly the chlorophyll contents in leaves of sugarcane cultivar ROC22 (increased by 23%),slightly in the other three sugarcane cultivars B8, GT21 and GT28, compared to the uninoculated controls. The net photosynthetic rates of sugarcane cultivar ROC22 and B8 are higher than the controls after 30 days, and there are significant differences. The net photosynthetic rates of the four sugarcane cultivars inoculated the strain after 60 days are higher than those after 30 days. The net photosynthetic rates of the four sugarcane cultivars are significantly higher than controls after the treatment 60 days. The effects of inoculation on the net photosynthetic rates are better in the cultivars ROC22 and GT21. The effects of the inoculation treatments on the nutrient element contents are different. The contents of N in the NFB inoculation treatment group are all higher than control group for the four sugarcane cultivars, especially incultivar ROC22(increased by 59.8%). There are no differences in the contents of P and K in all the cultivars between the inoculation treatment group and the control group. Among the four cultivars, the Zn content in leaves of ROC22 and the Cu contents in leaves of ROC22 and B8 are improved significantly by inoculating, compared with the control. 【Conclusions】 The effects of inoculating Klebsiella sp. 120 on the photosynthetic characteristics and mineral contents depend on sugarcane cultivars. The effect is most obvious in the sugarcane cultivar ROC22 among the selected four sugarcane cultivars.Therefore,experiment should be carried out for different sugarcane cultivars for the effective performance ofthe strain Klebsiella sp.120.