【作者】 刘建亲；

【导师】 花日茂；

【作者基本信息】 安徽农业大学 ， 农药学， 2008， 硕士

【摘要】 本实验检测了D3菌株对常用抗生素的抗性情况,其结果为:D3菌株对卡那霉素、四环素的抗性小于10μg·mL^-1,对氯霉素、链霉素、氨苄青霉素的抗性小于5μg·mL^-1,对新霉素、红霉素的抗性更小,分别为2μg·mL^-1和小于0.5μg·mL^-1。并对D3菌株进行了氯霉素的抗性驯化,使其对氯霉素的抗性达到30μg·mL^-1。对抗性驯化的菌株D3-X和出发菌株D3进行了降解毒死蜱能力的测定比较,结果显示,抗性驯化后并未影响出发菌株D3的降解毒死蜱的能力。将驯化菌株D3-X接种到土壤中研究其在土壤中的存活情况。结果表明,驯化菌株在自然土壤和灭菌土壤中均可以存活,在灭菌土壤中的定殖水平略高于自然土壤。驯化菌株接种到土壤后5d之内就已达到最高定殖水平,第5d时灭菌土壤处理的菌株定殖密度为4.9×10⁷cfu/g土,而在自然土壤处理的定殖密度为2.3×10⁷cfu/g土,随着时间的推移,定殖数量均呈下降趋势。在30d时向土壤中加入蛋白胨和酵母膏营养后,驯化菌株在自然土壤中的定殖水平会上升。驯化菌株在黄棕壤、黄红壤与砂姜黑土中的存活力研究表明,D3-X菌株在以上三种土壤中均可以存活且无明显差异,说明D3-X菌株在不同性状的土壤中均具有较强的定殖能力,适合土壤和植物根际污染修复。利用根盒实验研究D3-X菌株在植物根部的存活情况,结果发现,驯化菌株在土壤中垂直方向上主要定殖在0-10cm根段间,且随深度增加而降低。在蕃茄播种后10d以内D3-X就达到了最高定殖水平。第5d时,驯化菌株D3-X已经延伸到蕃茄种子以下根长6cm以内,在0-2cm和2-4cm根段的根际定殖密度分别为4.94×10⁶cfu/g根土和3.22×10⁶cfu/g根土。虽然此时有些番茄根长超过了6cm,但6cm以下根段并未检测到驯化菌株D3-X。到第10d时,番茄主根长已超过8cm,但驯化菌株主要定殖在8cm以内,在8cm以下根段根表土壤中未检测到驯化菌株。到第50d时,10cm根段以内根际和根表土壤中均有驯化菌株存活,2-4cm根段的根际定殖密度为8.45×10²cfu/g根土,0-2cm根段的根表定殖密度也高达1.11×10⁴ cfu/g根。无论在根表还是根际土壤中,在番茄根尖部位都未检测到菌株。由此可见,驯化菌株是从种子向根尖方向扩散的,但并不与根的生长同步,而是稍迟于根的伸长生长。比较接种菌株在番茄根际与根表定殖密度之间的关系,结果发现,根表的定殖密度高于根际土壤中的定殖密度。在番茄播种后同一时间检测驯化菌株,驯化菌株的定殖数量总体上是顺着根向下呈现出逐渐降低的趋势,即驯化菌株在离番茄种子越近的根段定殖数量越高;同一根段驯化菌株的根际定殖数量随着时间的延长而逐渐降低。利用盆栽实验研究D3菌株对土壤中毒死蜱污染的修复,结果表明,D3菌株对毒死蜱的降解随着初始菌量的增加,土壤中毒死蜱降解速率加快,半衰期缩短,修复作用和菌量成正相关。在相同的施菌量下对不同污染浓度的毒死蜱土壤进行修复时,在低污染浓度的土壤中,菌株对污染物修复效果好,毒死蜱的降解速率快,而在高污染浓度的土壤中修复效果略差一些,毒死蜱降解速率要慢一些。随着农药浓度的增加,修复效果依次下降。在同一施菌量下,种植番茄与不种植番茄的土壤中,种植番茄土壤中的毒死蜱降解速度要快于不种植番茄的土壤,特别是在低施菌量的条件下,种植植物对毒死蜱的降解动态的影响更为显著。更多还原

【Abstract】 D3 (Rhodococcus rhodochrous.) strains that had a capability to utilize chlorpyrifos as the sole carbon and energy sources. D3 strains resistant to commonly antibiotics is studied in paper, the results that D3 strain on kanamycin, tetracycline resistance is less than 10μg .mL(-1), for chloramphenicol, streptomycin, ammonia Benzyl penicillin resistance is less than 5μg .mL(-1), the neomycin, erythromycin resistance is smaller, 2μg .mL(-1) and less than 0.5μg .mL(-1) respectively. D3 strain of chloramphenicol resistance to the domestication, to the chloramphenicol resistance to 30μg .mL(-1).The domestication had no serious effect on the chlorpyrifos -degradation ability of the strain .After the domesticated strain D3-X was inoculated into the soil, the colonizing dynamics of the D3-X in soil were studied by the method of enumeration of luminescent colonies on agar media. The results showed that D3-X successfully colonized both in the sterile soil and unsterile soil, and colonizing level of D3-X in sterile soil was higher than that of unsterile soil. The population of D3-X reached to the highest level, 4.9×10~7cfu/g and 2.3×10~7cfu/g soil respectively in the sterile soil and unsterile soil after 5 days.With time delaying the population decreased. The population of D3-X rised when peptone and barm paste were added into soil. The results of survival ability of D3-X in Yellow-Brown Soil,Yellow -red Soil and Shajiang Black Soil meant that strain D3-X could compete with other microbes for space and nutrition in different soils.Being prepared as microbial inoculant and inoculated on seeds of tomato, the colonizing dynamics and distribution of the strain D3-X in soil and rhizosphere of tomato plant in rhizoboxes were studied by the method of enumeration of luminescent colonies on agar media. The results showed that the strain colonized mainly in 0-10cm root segment in vertical direction. The population of D3-X reached to the highest level before 10 days after seeds planted. On the 5th day D3-X spread 6cm below seeds, the population in 0-2cm and 2-4cm root segment was 4.94×10~6cfu/g rhizosphere soil, 3.22×10~6cfu/g rhizosphere soil respectively. No luminescent bacteria were detected below 6cm, although wheat root length was beyond 6cm. On the 10th day, D3strain colonized mainly in 0-8cm root segment, although tomato root length was beyond 10cm, and on the 50th day, the population of D3-X in 0-2cm root segment reached to 1.11×10~3cfu/g root-soil and in 2-4cm8.45×10~2cfu/g root respectively in tomato rhizosphere and tomato rhizoplane. The results of rhizobox culture experiment showed that D3-X spread from seeds toward the direction of root tip, but not synchronized with the stretch of roots. D3-X was not detected in the region of tomato root tip.Colonizing level of D3-X in tomato rhizoplane was higher than that of tomato rhizosphere, and the population of D3-X decreased gradually along the root. The data indicated that the colonizing level of strain D3-X was relative to the distance between the root segment and the seeds, the shorter the distance was, the higher the coloning level was. In addition, the population of D3-X in the same root segment decreased gradually with time delaying.Resarching the effect of D3 strain of Chlorpyrifos on Bioremediation, the results indicated that D3 strain on the degradation of chlorpyrifos as the initial amount of the increase, the rate of soil degradation of chlorpyrifos accelerated, shortening the half-life, bacteria and repair of a positive correlation .In same amount of bacteria,the effect of plant on the decomposition half life of Chlorpyrifos is very remarkable. The degradation rate of chlorpyrifos in soil planted tomatoes is faster than that in soil not planted tomatoes.更多还原