酸铝胁迫下难溶性磷对外生菌根真菌生长、无机磷形态及抗氧化酶活性的影响

发布时间：2018-04-29 10:42

本文选题：外生菌根真菌 + 铝毒　；参考：《西南大学》2017年硕士论文

【摘要】：磷是森林植被生长所必需的大量元素之一,其需求量仅次于氮。而土壤酸化引起的活性铝数量增多是土壤有效磷含量降低的主要原因之一。土壤有效磷的缺乏,严重限制了植物的正常生长。优良的外生菌根真菌(ECMF)可与大多数林木形成共生体,在提高植物抗铝毒能力,促进植物对养分元素特别是磷的吸收方面表现突出。试验选取了3种不同的ECMF——彩色豆马勃(Pisolithus tinctorius 715,简称Pt715)、松乳菇的两个株系(Lactarius deliciosus 2,简称Ld2;Lactarius deliciosus 3,简称Ld3)为研究对象,在液体纯培养条件下,研究了酸铝胁迫下难溶性磷对ECMF的生长、氮磷铝吸收、无机磷形态、抗氧化酶活性的影响,以及进行了菌株吸收铝、磷的动力学研究,以筛选出对难溶性磷利用效率高的优良ECMF,同时探索ECMF对难溶性磷的活化作用及机理,为我国酸性富铝林地上的植被修复提供理论和实践依据。具体的研究结果如下:(1)3种供试菌株均能耐受酸铝胁迫,且Fe-P处理对菌丝体生长的促进效果最明显。其中,Ld2表现出较强的耐铝性,在P0、Na-P、Fe-P和Al-P 4种处理下菌丝生物量均显著增加(P0.05),且增幅分别为Fe-P(22.31%)P0(15.87%)Na-P(8.87%)Al-P(6.91%);Pt715的菌丝生物量在Na-P、Fe-P、Al-P处理下显著增加,且Fe-P(32.84%)Na-P(15.35%)Al-P(7.66%);Ld3的菌丝生物量在Na-P和Fe-P处理下显著增加,且Fe-P(17.19%)Na-P(14.06%)。铝胁迫时,难溶性Fe-P、Al-P、Na-P处理下的菌株生长均好于P0处理,且Fe-P效果最好,Al-P次之,Na-P最小。3种菌株中,生物量高低依次为Ld2Ld3Pt715,即Ld2在酸铝胁迫下各种磷处理中的生长速度均优于Ld3和Pt715。(2)3种菌株使培养液的pH值降低,但铝胁迫下pH升高。铝胁迫时,Fe-P和Al-P处理下的菌液pH值均小于Na-P,推测ECMF可能通过分泌H+或有机酸溶解难溶性Fe-P和Al-P、络合Al3+、调节培养环境的pH值来达到抗铝解磷作用。(3)Fe-P和Al-P均促进菌丝体对铝、总磷、Fe-P、Al-P的吸收,但抑制对氮的吸收。酸铝胁迫下菌株对氮、铝、总磷及Al-P的吸收增加。无铝时,3种菌株在Fe-P处理下菌丝体中Fe-P含量最高,但铝胁迫却使其显著降低,而且各菌株在4种磷源处理下均为Al-P含量及占比最高,推测铝可能竞争铁的吸附位点且与磷结合有优先选择性,进而使Fe-P化合物或其他磷形态含量降低。3种菌株中,菌丝体内含磷量高低依次为Ld3Ld2Pt715,即Ld3对磷的利用能力强于Ld2和Pt715。(4)酸铝胁迫显著提高ECMF的SOD、CAT酶活性,但降低POD酶活性(P0.05)。难溶性Fe-P、Al-P处理下的菌丝体SOD、POD、CAT酶活性均高于Na-P,说明难溶性磷处理有利于抗氧化酶升高;铝胁迫使Ld2的SOD、CAT酶活性增幅均大于Ld3和Pt715,POD酶活性降幅均小于Ld3和Pt715,推测Ld2的抗铝胁迫能力较强。(5)相关性分析表明,3种ECMF的总P、Al、Al-P含量呈两两极显著正相关(P0.01),说明P与Al的吸收有协同促进作用,Al-P随总P和Al含量的增多而增多,推测Al和P在进入菌丝体内仍可能相互结合。SOD与CAT酶活性呈极显著正相关,说明SOD与CAT协同促进消除抗氧自由基。SOD、CAT酶活性与P、Al-P含量呈显著正相关(P0.05),说明菌株通过提高SOD、CAT酶活性,抗铝胁迫和活化难溶性磷能力增强。(6)3种菌株的CEC大小依次为Ld3≥Ld2Pt715,推测Ld3和Ld2对Al3+的吸附量大于Pt715。总的来看,Ld3、Ld2吸收铝的Km大、Imax大,表明松乳菇更能适应高浓度铝的土壤环境。(7)铝胁迫下,除Ld2的C_(min)无明显变化外,ECMF吸收磷的Km和C_(min)值均减小,Imax值均增大,即铝增强了菌株吸收磷的能力,并且供试菌株均能够适应低磷的土壤环境。松乳菇的两个株系Ld2和Ld3吸收磷的Km和Imax均小于Pt715,说明松乳菇更能适合低磷的土壤环境。综上,试验所用的3种菌株在酸铝胁迫下均能适应高铝低磷环境,活化利用难溶性磷,且Ld2和Ld3的适应能力和活化利用能力均强于Pt715。其中,Ld2生长速度最快、抗铝性最强,Ld3吸收磷的能力最强。3种菌主要通过分泌H+或有机酸、促进Al-P、Fe-P溶解、增加对养分磷的吸收,增加对Al的吸收或吸附,络合Al3+,提高SOD、POD、CAT酶活性,来活化酸性铝胁迫下的难溶性磷。
[Abstract]:Phosphorus is one of the most important elements necessary for the growth of forest vegetation, and its demand is second only to nitrogen. The increase in the amount of active aluminum caused by soil acidification is one of the main reasons for reducing the content of effective phosphorus in the soil. The lack of available phosphorus seriously restricts the normal growth of plants. The excellent ectomycorrhizal fungi (ECMF) can be formed with most trees. Symbionts, in improving plant resistance to aluminum toxicity and promoting plant uptake of nutrient elements especially phosphorus, have selected 3 different kinds of ECMF - color bean (Pisolithus tinctorius 715, Pt715), two strains of Lactobacillus Pleurotus (Lactarius deliciosus 2, Ld2; Lactarius deliciosus 3, Ld3) as research Under the condition of liquid pure culture, the effects of soluble phosphorus on the growth of ECMF, the absorption of nitrogen, phosphorus and aluminum, the effect of the inorganic phosphorus form and the activity of antioxidant enzymes were studied, and the kinetics of the absorption of aluminum and phosphorus by strains was carried out to screen out the excellent ECMF with high efficiency of soluble phosphorus, and the activity of ECMF to the insoluble phosphorus was also explored. The effect and mechanism of the study provide theoretical and practical basis for the vegetation restoration on the acid rich aluminum forest in China. The results are as follows: (1) 3 strains of strain can tolerate aluminum stress, and the effect of Fe-P treatment on mycelium growth is the most obvious. Among them, Ld2 shows a strong resistance to aluminum, and 4 kinds of bacteria are treated in P0, Na-P, Fe-P and Al-P. The biomass increased significantly (P0.05), and the increase was Fe-P (22.31%) P0 (15.87%) Na-P (8.87%) Al-P (6.91%), and the mycelial biomass of Pt715 increased significantly under Na-P, Fe-P, Al-P, and Fe-P (32.84%) Na-P (15.35%) Al-P (7.66%). The growth of strain Fe-P, Al-P and Na-P was better than P0 treatment, and the effect of Fe-P was the best, Al-P was the best. In Na-P smallest.3 strain, the biomass of the strain was in turn Ld2Ld3Pt715, that is, the growth rate of Ld2 in all kinds of phosphorus treatments under aluminum acid stress was superior to Ld3 and Pt715. (2) 3 strains to reduce the value of the culture solution, but increased under aluminum stress. When aluminum stress was stressed, the pH value of the bacterial solution under Fe-P and Al-P treatment was less than Na-P. It is suggested that ECMF may dissolve difficult Fe-P and Al-P by secreting H+ or organic acid, complexing Al3+ and adjusting the pH value of the culture environment to achieve the effect of anti aluminum phosphate hydrolysis. (3) Fe-P and Al-P all promote the absorption of aluminum, total phosphorus, and nitrogen, but inhibit the absorption of nitrogen. Aluminum stress The absorption of nitrogen, aluminum, total phosphorus and Al-P by the lower strains increased. When the 3 strains were free of aluminum, the content of Fe-P was the highest in the hypha under Fe-P treatment, but the aluminum stress was significantly reduced, and all the strains were Al-P content and the highest proportion under the treatment of 4 kinds of phosphorus sources. Among the Fe-P compounds or other phosphorus forms, the level of phosphorus content in the hyphae of.3 strains was Ld3Ld2Pt715, that is, the utilization of Ld3 to phosphorus is stronger than that of Ld2 and Pt715. (4). The activity of SOD and CAT enzyme in ECMF is significantly increased, but the POD enzyme activity (P0.05) is reduced. Na-P, indicating that the treatment of soluble phosphorus is beneficial to the increase of antioxidant enzymes; aluminum coerced Ld2 SOD, CAT enzyme activity increased more than Ld3 and Pt715, POD enzyme activity decreased less than Ld3 and Pt715, and speculates that Ld2 is stronger in resistance to aluminum stress. (5) correlation analysis shows that the total P of the 3 ECMF is two and two poles. Al-P increased with the increase of total P and Al content. It is suggested that Al and P may still have a significant positive correlation with the activity of.SOD and CAT enzyme in the hyphae into the mycelium, indicating that SOD and CAT synergistically promote the elimination of oxygen free radicals,.SOD, and the activity of CAT enzyme is significantly positively correlated with P. The activity of AT enzyme, resistance to aluminum stress and activation of insoluble phosphorus increased. (6) the CEC size of 3 strains was Ld3 > Ld2Pt715 in turn. The adsorption amount of Ld3 and Ld2 on Al3+ was greater than Pt715., Ld3, Ld2 absorption of aluminum was large and Imax was large, indicating that the mushroom could adapt to the soil environment of high concentration aluminum. (7) there was no obvious change under aluminum stress. In addition, the Km and C_ (min) value of ECMF absorption decreased and the Imax value increased, that is, aluminum enhanced the ability to absorb phosphorus, and the tested strains were able to adapt to the low phosphorus soil environment. The Km and Imax of the two strains of Lactobacillus Pleurotus, Ld2 and Ld3, were less than Pt715, indicating that Lactobacillus Pleurotus can be more suitable for low phosphorus soil environment. The 3 strains can adapt to the environment of high aluminum and low phosphorus under the stress of aluminum and activate the refractory phosphorus, and the adaptability and activation ability of Ld2 and Ld3 are stronger than that of Pt715.. Ld2 has the fastest growth rate and the strongest aluminum resistance. The strongest.3 bacteria of Ld3 absorb the H+ or organic acids, which can promote Al-P, Fe-P dissolve and increase the nutrition. The absorption of phosphorus increased the absorption and adsorption of Al, complexed Al3+, enhanced SOD, POD and CAT enzyme activities to activate the insoluble phosphorus under acidic aluminum stress.

【学位授予单位】：西南大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S718.81

【参考文献】