由于人为活动的加速而造成的环境污染已成为对现代人类的严重威胁。在污染物中,新出现的问题是环境中的重金属(HM)污染。由于重金属的持久性和危害性影响着生态系统和植物的健康,动物,和人类,它们是环境中最有毒的物质。其中,砷(As)成为主要的环境约束,对植物产生巨大的负面影响,动物,和人类健康。即使在微小的数量,众所周知,它会在人类中引起各种重大疾病,并在植物中引起毒性。进行了研究,以观察促进植物生长的细菌菌株增强玉米的能力(L.)在砷污染土壤中的生长。从污染土壤中分离出30株细菌,筛选植物生长促进潜力和耐砷性。在使用LB培养基的琼脂平板中,有18个分离株对不同水平的砷酸钠(0至50mM)具有抗性。在18个分离株中,产生了83.3%的IAA,甲基红,和氰化氢;55.5%显示过氧化氢酶活性;61.1%显示铁载体产生;88.8%显示磷酸盐溶解;44.4%显示氧化酶,VogesProskauer活动,和KOH溶解度。通过对扩增的16SrRNA基因进行测序,检查了具有显着的砷耐受性和植物生长促进(PGP)活性的最有效的分离株SR3,SD5和MD3。细菌的分离,即,SR3,SD5和MD3,显示多个PGP性状被鉴定为短小芽孢杆菌(NCBI登录号:OR459628),粪类芽孢杆菌(NCBI登录号:OR461560),和伪嗜酸杆菌(NCBI登录号:OR458922),分别。用这些PGPR菌株处理的玉米种子在被50ppm和100ppm砷酸钠污染的盆中生长。与未经处理的砷胁迫植物相比,细菌接种糖原(MD3)的结果为20.54%,18.55%,33.45%,45.08%,光合色素提高48.55%(类胡萝卜素含量,叶绿素含量,气孔导度(gs),气孔下CO2和光合速率),分别。主成分分析解释说,对于每个测试参数,前两个成分的变异性超过96%。结果表明,与其他分离株相比,在砷污染的土壤中,解糖假单胞菌可作为改善玉米生长的有效药剂。
Contamination of the environment due to speedup of anthropogenic activities has become a serious threat to modern humanity. Among the contaminants, the new emerging concern is the heavy metal (HM) contamination in the environment. Because the persistence and harmfulness of heavy metals affect the ecosystem and the health of plants, animals, and humans, they are the most toxic substances in the environment. Among them, Arsenic (As) emerged as major environmental constraint leading to enormous negative effects on the plant, animal, and human health. Even in minute quantity, As is known to cause various critical diseases in humans and toxicity in plants. Research was performed to observe the capability of plant growth-promoting strains of bacteria in enhancing Zea mays (L.) growth in arsenic polluted soil. Total 30 bacterial strains were isolated from the polluted soils, screened for plant growth promotion potential and arsenic tolerance. Eighteen isolates showed resistance to different levels of sodium arsenate (ranging from 0 to 50 mM) in agar plate using LB media. Of 18 isolates, 83.3% produced IAA, methyl red, and hydrogen cyanide; 55.5% exhibited catalase activity; 61.1% showed siderophore production; 88.8% showed phosphate solubilization; and 44.4% showed oxidase, Voges proskauer activity, and KOH solubility. The most efficient isolates SR3, SD5, and MD3 with significant arsenic tolerance and plant growth-promoting (PGP) activity were examined via sequencing of amplified 16S rRNA gene. Isolates of bacteria, i.e., SR3, SD5, and MD3, showing multiple PGP-traits were identified as Bacillus pumilus (NCBI accession number: OR459628), Paenibacillus faecalis (NCBI accession number: OR461560), and Pseudochrobactrum asaccharolyticum (NCBI accession number: OR458922), respectively. Maize seeds treated with these PGPR strains were grown in pots contaminated with 50 ppm and 100 ppm sodium arsenate. Compared to untreated arsenic stressed plants, bacterial inoculation P. asaccharolyticum (MD3) resulted 20.54%, 18.55%, 33.45%, 45.08%, and 48.55% improvement of photosynthetic pigments (carotenoid content, chlorophyll content, stomatal conductance (gs), substomatal CO2, and photosynthetic rate), respectively. Principal component analysis explained that first two components were more than 96% of the variability for each tested parameter. The results indicate that in comparison to other isolates, P. asaccharolyticum isolate can be used as efficient agent for improving maize growth under arsenic polluted soil.