A pot study was performed to examine the effect of plant growth-promoting rhizobacteria (PGPR) including Azospirillum lipoferum or Azotobacter chroococcum on growth criteria (leaf area and seedlings fresh and dry weight), pigments [chlorophylls (Chl a and b) and carotenoids], osmolytes (soluble sugars, soluble proteins and proline), nutrient uptake, antioxidant enzyme activities, and oxidative stress in maize plants under normal and salt-affected soils. The results showed that salt stress induced a reduction in growth traits, pigments, soluble proteins, K+, and K+/Na+ ratio. On the other side, it increased soluble sugars, proline, Na+, malondialdehyde (MDA), and the activity of peroxidase (POD) and catalase (CAT). Meanwhile, salt stress did not significantly change the activity of ascorbate peroxidase (APX) in maize plants. The inoculation using Azospirillum lipoferum or Azotobacter chroococcum significantly enhanced growth parameters, pigments, K+, osmolytes, K+/Na+ ratio, and the activity of CAT, POD, and APX of the salt-affected maize plants as well as uninoculated control plants. In addition, the results showed that both types of bacteria have attributed to lower MDA and Na+ in maize plants. Interestingly, Azospirillum lipoferum has affected more compared to Azotobacter chroococcum in control and salt-stressed plants. We, therefore, have observed in this study that microbial inoculation significantly improved plant physiological activities and that adding bacteria such as Azospiroillum or Azotobacter to the soil could mitigate the negative effects of salt stress on maize plants.

中文翻译：

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接种脂固氮螺菌或色球菌固氮菌通过改善盐分条件下的生理活动来增强玉米的生长

进行了一项盆栽研究，以检查促进植物生长的根际细菌 (PGPR) 对生长标准（叶面积和幼苗鲜重和干重）、色素 [叶绿素（叶绿素（Chl a 和 b）和类胡萝卜素）的影响，包括固氮螺菌或色球固氮菌] 、渗透质（可溶性糖、可溶性蛋白质和脯氨酸）、养分吸收、抗氧化酶活性和正常土壤和盐渍土壤下玉米植株的氧化应激。结果表明，盐胁迫导致生长性状、色素、可溶性蛋白质、K+ 和 K+/Na+ 比率降低。另一方面，它增加了可溶性糖、脯氨酸、Na+、丙二醛 (MDA) 以及过氧化物酶 (POD) 和过氧化氢酶 (CAT) 的活性。同时，盐胁迫没有显着改变玉米植株抗坏血酸过氧化物酶（APX）的活性。使用 Azospirillum lipoferum 或 Azotobacter chroococcum 接种显着提高了受盐影响的玉米植物以及未接种对照植物的生长参数、色素、K+、渗透物、K+/Na+ 比率以及 CAT、POD 和 APX 的活性。此外，结果表明，这两种细菌都归因于玉米植株中较低的 MDA 和 Na+。有趣的是，在对照和盐胁迫的植物中，与色球菌固氮菌相比，固氮螺菌的影响更大。因此，我们在本研究中观察到微生物接种显着改善了植物的生理活动，向土壤中添加固氮螺菌或固氮菌等细菌可以减轻盐胁迫对玉米植物的负面影响。