ABSTRACT

The information about the use of plant growth-promoting endophytic bacteria (PGPEB) with ornamental plants is still scarce. This study was designed to isolate and characterize PGPEB from different plants (Gossypium, Cyperus, Corchorus olitorius and Oryza sativa) and to evaluate their potential in plant growth promotion in tuberose (Polianthes tuberosa L.). A total of 25 isolates were obtained from the surface-disinfected plant parts. Five isolates were initially selected for their ability to produce indole-3-acetic acid and phosphate-solubilization activity in addition to the ability to form a biofilm. The most potent isolate was selected and identified as Klebsiella variicola RS-1. A pot experiment was designed to examine the ability of the selected isolate to aid tuberose withstanding different concentration of irrigation water salinity with EC values of 1.2 (control), 4.5, 6, and 7.5 ds m^-1 during two successive growing seasons. At higher salinity levels (7.5 ds m^-1), both inoculated and sprayed plants recorded high levels of catalase and peroxidase activities 3 and 1.5 times over untreated plants respectively. Also, leaf length was increased about 46% and 37% in inoculated and sprayed plants respectively over untreated ones. The same trend was observed in most other vegetative parameters.

摘要

关于将植物促生长内生细菌 (PGPEB) 用于观赏植物的信息仍然很少。本研究旨在分离和表征来自不同植物（棉、香附、Corchorus olitorius 和 Oryza sativa）的PGPEB，并评估它们在晚香玉 ( Polianthes tuberosa  L.) 中促进植物生长的潜力。从表面消毒的植物部分共获得 25 个分离株。除了形成生物膜的能力外，最初选择了五个分离株，因为它们能够产生吲哚-3-乙酸和磷酸盐溶解活性。选择了最有效的分离株并鉴定为 水痘克雷伯菌 RS-1。盆栽实验旨在检查所选分离株 在两个连续生长季节期间帮助晚香玉耐受不同浓度灌溉水盐度的能力，  EC 值为 1.2（对照）、4.5、6 和 7.5 ds m ^-1。在较高的盐度水平 (7.5 ds m ^-1 ) 下，接种和喷洒的植物都记录了高水平的过氧化氢酶和过氧化物酶活性，分别是未处理植物的 3 倍和 1.5 倍。此外，与未处理的植物相比，接种和喷洒植物的叶长分别增加了约 46% 和 37%。在大多数其他植物参数中观察到相同的趋势。