Effects of Solution Applied and Different Encapsulation Method of Plant Growth Promoting Bacteria (PGPB) on the Physiological Response of Sunflower to Drought Stress

Improving drought tolerance in pre-sprouted sugarcane through inoculation with plant growth-promoting bacteria: assessment of biochemical activity, nutrient uptake, and physiological performance

Pre-sprouted sugarcane seedlings are increasingly used to ensure uniform crop establishment; however, their performance is highly constrained by water deficit under climate change scenarios. This research evaluated whether a consortium of Bacillus licheniformis (FMCH001) and Bacillus subtilis (FMCH002) could mitigate drought stress by improving root development, soil microbial activity, and plant nutritional and physiological responses under different water regimes. The experiment was conducted in a randomized block design using a 4 × 2 factorial scheme, with four water regimes (20, 40, 60, and 80% of field capacity) and two inoculation treatments (with and without bacteria), with four replicates. Bacillus inoculation alleviated the adverse effects of water deficit, particularly under severe water restriction (20, 40, and 60% of field capacity), by increasing root length, surface area, volume, and diameter. Inoculated treatments showed higher arylsulfatase, β-glucosidase, acid phosphatase, and urease activities, indicating enhanced soil microbial functioning. These responses were associated with increased leaf concentrations of N, P, K, Ca, Fe, and Zn. Furthermore, inoculated plants exhibited improved photosynthetic performance, including higher PSII efficiency, electron transport rate, net CO 2 assimilation, water use efficiency, and carboxylation efficiency, contributing to better establishment and development throughout the sugarcane growth cycle. Inoculation with Bacillus subtilis and Bacillus licheniformis mitigated the effects of water deficit in pre-sprouted sugarcane seedlings by promoting root development, enhancing soil microbial activity, and increasing nutrient acquisition, thereby improving plant mineral nutrition and photosynthetic performance.

Interactive effects of plant growth-promoting rhizobacteria and drought stress on the growth and yield of shallot (Allium ascalonicum L.) cultivated in saline soil

This study evaluated the effects of plant growth-promoting rhizobacteria (PGPR) and drought-stress timing on the growth, yield, and physiological responses of shallot ( Allium ascalonicum L.) cultivated in saline soil. The experiment was conducted using a factorial randomized block design with PGPR concentrations of 0, 20, and 40 mL L⁻¹ and drought-stress timing consisting of no stress, early growth stress (1–14 DAP), vegetative stress (15–28 DAP), and bulb formation stress (29–42 DAP). The final soil EC reached 6 dS m⁻¹, while soil moisture during drought periods declined to 30–50%. PGPR improved plant length, leaf area, tiller number, plant dry weight, and net assimilation rate. PGPR at 40 mL L⁻¹ was more effective for vegetative growth, whereas 20 mL L⁻¹ tended to enhance proline and flavonoid accumulation. Drought during early and vegetative phases caused the greatest reductions in growth and yield. These findings indicate that PGPR supports shallot performance in saline soil, but its effectiveness depends strongly on water availability during critical growth phases.

Physiological and molecular responses of lentil to plant growth-promoting rhizobacteria (PGPR) inoculation and targeted foliar application of melatonin and spermidine under dryland drought stress

Evaluation of Drought Tolerance in In Vitro potato (Solanum tuberosum L.) cv. Dayang Sumbi Plantlets Using Polyethylene Glycol (PEG) 6000

Potato (Solanum tuberosum L.) is an important food crop whose productivity tends to decline under drought stress conditions. Water deficit limits water uptake, reduces cell turgor pressure, and disrupts photosynthesis, resulting in inhibited plant growth. Development of drought-tolerant potato cultivars can be achieved through in vitro culture using polyethylene glycol (PEG) 6000 as a selective agent that lowers the water potential of the culture medium without causing direct damage to plant cells. This study aimed to evaluate the effect of PEG 6000 on the growth of in vitro potato plantlets of the Dayang Sumbi cultivar and to determine the concentration that could still be tolerated under drought stress conditions. The experiment was conducted at the Botany Laboratory, Faculty of Mathematics and Natural Sciences, Universitas Lampung, using a Completely Randomized Design (CRD) with five PEG 6000 concentrations (0%, 5%, 10%, 15%, and 20%) and five replications. The observed parameters included plantlet survival percentage, plantlet height, number of leaves, and stomatal index. The data were analyzed using analysis of variance (ANOVA) followed by Tukey's Honestly Significant Difference (HSD) test at a 5% significance level. The results showed that all plantlets remained viable, with a 100% survival rate across all PEG 6000 concentrations during the two-week observation period. Significant differences were observed in plantlet height, leaf number, and stomatal index, all of which decreased progressively with increasing PEG 6000 concentration and reached their lowest values at 20% PEG 6000. A PEG 6000 concentration of 10% was found to support the growth tolerance of Solanum tuberosum L. cv. Dayang Sumbi plantlets under in vitro drought stress conditions.

Potential of Bacillus aryabhattai and Pseudomonas fluorescens for Promoting Plant Growth under Water Stress

The findings demonstrate the potential of B. aryabhattai and P. fluorescens as plant growth-promoting bacteria capable of enhancing soybean development, with B. aryabhattai showing particular promise for improving plant performance under water-limited conditions.

Exogenously Applied Vanillic Acid Confers Drought Resilience in Cabbage (Brassica oleracea var. capitata L.) by Modulating Morpho-Physiological and Biochemical Responses

F foliar application of exogenously used vanillic acid resulted in significant improvements in plant morphology and in physiological and biochemical traits, thereby improving stress tolerance, maintaining cellular functions, and enhancing growth and development in cabbage plants.