MANPREET KAUR, MUKESH KUMAR, POOJA SHARMA, ROHIT GOYAT, TAPAN KUMAR MUKHERJEE AND ARUN KARNWAL
Department of Sciences, Chandigarh School of Business, Chandigarh Group of Colleges, Jhanjeri, Mohali-140 307 (Punjab), India
*(e-mail: arunkarnwal@gmail.com; Mobile: 70186 08676)
(Received: December 26, 2024; Accepted: February 7, 2025)
ABSTRACT
Rheum emodi, a perennial herb thriving at high altitudes (1800-4400 m), possesses numerous medicinal properties. However, the plant faces endangerment in its natural habitat due to excessive exploitation. Current research was aimed at investigating the effect of stress-tolerant endophytic bacteria on the growth of R. emodi cultivated at lower altitudes (748 ft) under salt and heavy metal stress. Endophytic bacteria, namely, Pelomonas aquatica AIS1S and Solibacillus silvestris DL3R2, were isolated from Abutilon indicum and Hermocallis fulva, respectively, and identified using 16s rRNA sequencing. Seeds were inoculated with these bacteria and planted in sterile soil with low carbon, potassium and phosphorus content. Plant growth was monitored over three months, and the phytochemical composition of the experimental plants was compared with that of in situ plants serving as control. The results indicated that seeds inoculated with P. aquatica AIS1S and S. silvestris DL3R2 exhibited higher germination rates than control. The highest germination rate 2.33±0.47 was observed at a 2% salt concentration upon inoculation with P. aquatica AIS1S, while the lowest 0.33±0.47 was recorded at a 6% cadmium concentration upon inoculation with P. aquatica AIS1S. High-Performance Liquid Chromatography (HPLC) analysis revealed that root samples collected from the experimental site (lower altitude) exhibited higher levels of quercetin (0.47%) and gallic acid (0.18%) compared to those from higher altitudes (natural site), which contained 0.41% quercetin and 0.16% gallic acid. Additionally, emodin, physcion, and rhein were identified as other compounds in the root samples at 254 nm.This study provided a basis that plants can be grown under stress conditions with the help of stress-tolerant endophytic bacteria, thus providing a new strategy for the conservation of plants.
Key words: Rheum emodi, Pelomonas aquatica AIS1S, Solibacillus silvestris DL3R2, lead, cadmium, quercetin