Salinity is a major abiotic stress limiting canola ( Brassica napus L.) productivity, especially in arid regions. This study aimed to evaluate the efficiency of plant growth-promoting rhizobacteria (PGPR) in enhancing early seedling tolerance to graded sodium chloride (NaCl) stress and to compare single- and multi-strain inoculations. A greenhouse experiment was conducted under NaCl concentrations ranging from 0 to 200 mM using three treatments: uninoculated control, single strain ( Bacillus subtilis , SB), and a triple-strain consortium ( Bacillus megaterium + Pseudomonas fluorescens + B. subtilis , TB). Growth, physiological, and biochemical traits were analysed, including relative water content (RWC), electrolyte leakage (EC), photosynthetic pigments, phenolic compounds, oxidative stress markers, and antioxidant enzyme activities such as superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), and ascorbate peroxidase (APX). Salinity significantly reduced relative water content (RWC) from 60.10% to 48.63% and increased electrolyte leakage (EC) from 62.79% to 77.95%. TB inoculation mitigated these effects by maintaining higher RWC (53.57%) and lower EC (66.40%) than the control (71.93%). TB-treated plants showed higher chlorophyll (0.84 mg g⁻¹ FW), phenolics (10.34 mg GAE g⁻¹ DW ) , flavonoids (4.10 mg QE g⁻¹ DW ) , antioxidant capacity (85.98%), and proline (122.36 mg g⁻¹ FW ) compared to controls. Oxidative damage decreased, with hydrogen peroxide (H₂O₂) and malondialdehyde (MDA) reduced to 14.01 µmol g⁻¹ FW and 60.22 nmol g⁻¹ FW, respectively. Enzymatic responses differed: SB enhanced SOD and CAT under moderate salinity, while TB increased POD and APX activities under mild stress. PGPR inoculation, particularly multi-strain consortia, alleviates salt-induced oxidative stress and improves osmotic adjustment and antioxidant defense in canola seedlings, offering an eco-friendly strategy for sustainable production in saline soils. Graphical Abstract

This study aimed to compare the accumulation of secondary metabolites in root and stem tissues of Echinacea purpurea and Echinacea pallida grown in vitro on different basal media (MS, WPM, B5). Five major caffeic acid derivatives (CADs: caftaric, chlorogenic, caffeic, echinacoside, and cichoric acid), total phenolic content (TPC), total flavonoid content (TFC), and total antioxidant capacity (TAC) were measured. In E. pallida, the highest levels of caftaric acid (11.29 ± 0.06 mg/g DW) and cichoric acid (11.79 ± 0.01 mg/g DW) were found in root tissues on B5 medium, while echinacoside reached 8.29 ± 0.26 mg/g DW on WPM. Chlorogenic acid was most abundant in roots on MS (1.57 ± 0.06 mg/g DW). Caffeic acid was found in low amounts in WPM and B5 media only. In E. purpurea, cichoric acid reached the highest value overall in B5-grown root tissue (70.64 ± 0.41 mg/g DW). The same tissue also showed high caftaric (11.05 ± 0.03 68 mg/g DW) and caffeic acid (0.35 ± 0.0168 mg/g DW) levels. Chlorogenic acid peaked in WPM roots (5.25 ± 0.68 mg/g DW). Echinacoside was not detected in this species. Antioxidant parameters also differed significantly by species, tissue, and medium. In E. purpurea root tissues, the highest TPC (69.12 ± 1.98 mg GAE/g DW) and TFC (15.74 ± 0.93 mg QE/g DW) were found in B5 medium, while the highest TAC (%85.90) was recorded in WPM. E. pallida generally had lower antioxidant values. Overall, secondary metabolite accumulation was strongly influenced by species, tissue type, and medium. B5 was most effective for CADs, and WPM supported greater antioxidant capacity. E. purpurea outperformed E. pallida in both cichoric acid content and antioxidant potential, indicating its promising potential for targeted metabolite production in plant tissue culture.

Background: Salvia halophila Hedge is an endemic sage species confined to the salt steppe ecosystems of Central Anatolia (Türkiye), particularly around the Lake Tuz Basin, and is classified as Endangered (EN) by the IUCN. Its narrow distribution, low seed germination rates, and habitat pressures threaten its survival and restrict the sustainable exploitation of its valuable phytochemicals, such as rosmarinic acid and other phenolics. In vitro micropropagation represents a strategic approach for producing genetically uniform and phytochemically rich plant material, thereby supporting both ex situ conservation and biotechnological applications. Results: Three germination strategies were compared. Chemical priming and direct gibberellic acid (GA₃) applications were largely ineffective, whereas in vitro germination on GA₃-enriched media produced viable seedlings. WPM medium supplemented with 0.5–1.0 mg L⁻¹ GA₃ achieved the highest germination rate (20%). The optimized sterilization treatment minimized fungal contamination (4.4%) while sustaining a high proportion of healthy shoots (73%). For shoot induction, MS medium consistently outperformed WPM, achieving 78% induction and 1.51 shoots per explant versus 50% and 0.86 on WPM. Among cytokinins, meta-topolin (mT) provided the most reliable results, ensuring 90–100% shoot induction with high shoot quality at 0.2–1.0 mg L⁻¹. Rooting experiments demonstrated the superiority of IBA over NAA, with 0.5 mg L⁻¹ IBA yielding 66% rooting and 77% acclimatization. Biochemical profiling showed that micropropagated plantlets accumulated higher phenolic contents (TPC = 15.9 mg GAE g⁻¹ DW) and stronger antioxidant capacity (IC₅₀=24.6 µg mL⁻¹) compared with seed-derived plants. Conclusion: The study successfully established a stage-specific and efficient micropropagation protocol for S. halophila . While WPM medium was more favorable for seed germination, MS medium supplemented with mT and IBA was optimal for shoot regeneration and rooting. The protocol not only enhances propagation efficiency but also increases secondary metabolite accumulation, providing a reliable platform for conservation, sustainable utilization, and potential commercial production of this endangered halophyte.

Bu araştırmada, tuz stresine maruz bırakılan kanola (Brassica napus L.) tohumlarına salisilik asit (SA) ve askorbik asit (AsA) ile priming yapılarak çimlenmeye etkilerinin belirlenmesi ve bu uygulamaların optimum konsantrasyonlarının tespit edilmesi amaçlanmıştır. Araştırmada, 5 farklı NaCI konsantrasyonu (kontrol, 50, 100, 150, 200 mM) ile 2 farklı priming uygulaması (SA ve AsA ) ve her priming uygulamasının 5 farklı konsantrasyonu (kontrol, 0.5, 1.0, 1.5, 2.0 mM) ele alınmıştır. Çalışma tesadüf parsellerinde faktöriyel deneme desenine göre dört tekerrürlü olarak yürütülmüştür. Araştırma sonucunda çimlenme oranı (%), ortalama çimlenme süresi (gün) ve çimlenme indeksi (hızı) değerleri incelenmiştir. SA uygulamaları arasında, 0.5 mM SA konsantrasyonunun, artan tuz dozlarında tuz stresinin olumsuz etkisini azaltarak çimlenmeyi hızlandırdığı, ortalama çimlenme süresini kısalttığı ve çimlenme oranını artırdığı tespit edilmiştir. SA konsantrasyonu artıkça (1.5 mM ve 2.0 mM SA) tüm tuz uygulamalarında çimlenmenin olumsuz etkilendiği belirlenmiştir. AsA uygulamaları arasında ise 0.5, 1.0, 1.5 mM konsantrasyonlarının, tuz stresinin olumsuz etkisini büyük ölçüde azaltarak çimlenme oranı ve çimlenme indeksi değerlerine olumlu etkide bulunduğu belirlenirken, ortalama çimlenme süresi üzerine etki etmediği tespit edilmiştir. Kanola tonumlarına çimlenme öncesi uygulanan SA ve AsA ile priming uygulamalarının, tuz stresinin çimlenme engelleyici etkisini önemli ölçüde ortadan kaldırdığı saptanmış olup, 0.5 mM SA/AsA konsantrasyonları optimum doz olarak belirlenmiştir.

Bu araştırmada, tıbbi özelliklere sahip endemik Astragalus trojanus Stev. bitkisinin nodal kültürler ile klonal çoğaltımı amaçlanmıştır. Tohumlar Murashige ve Skoog (MS) besin ortamında çimlendirilmiş ve elde edilen steril fidelerin nodal segmentleri eksplant olarak kullanılmıştır. İlk olarak MS ve Woody Plant Medium (WPM) besin ortamlarının sürgün çoğaltımına etkileri araştırılmıştır. Eksplantlar farklı konsantrasyonlarda (0.2, 0.5, 1.0, 2.0 mg/L) 6-benzil amino purin (BAP) içeren MS ya da WPM besin ortamlarında kültüre alınmıştır. Kültürden 4 hafta sonra en fazla sürgün sayısı (2.80 adet/eksplant) 0.5 mg/L BAP içeren WPM ortamında elde edilmiştir. Çalışmanın devamında nodal segmentler, sitokinin kaynağı ve konsantrasyonlarının sürgün çoğaltımına etkisini belirlemek amacıyla BAP, thidiazuron (TDZ), kinetin (KIN)’in farklı konsantrasyonlarını (0.2, 0.5, 1.0, 2.0 mg/L) içeren WPM temel besin ortamında kültüre alınmıştır. 4 hafta sonunda elde edilen sürgün sayıları bakımından TDZ ve KIN’in benzer etki gösterdiği, en yüksek sürgün sayısının (2.09 adet/eksplant) BAP’dan elde edildiği tespit edilmiştir. Rejenere sürgünler köklenme için 1 veya 3 mg/L indol-3-butirik asit (IBA), naftalen asetik asit (NAA) veya indol-3-asetik asit (IAA) içeren WPM ortamlarına aktarılmıştır. Kültürden 4 hafta sonra en yüksek köklenme yüzdesi (%80) 3 mg/L IBA içeren WPM ortamından elde edilirken, en fazla kök sayısı (4.33 adet/eskplant) 3 mg/L IAA içeren WPM ortamından elde edilmiştir. Köklenen bitkicikler 1:1 oranında torf ve perlit içeren plastik bardaklara aktarılarak dış ortama başarıyla alıştırılmış ve tam bitki gelişimi 15 hafta sonunda tamamlanmıştır. Bu araştırma ile, Astragalus trojanus Stev. endemik türünde etkili bir klonal çoğaltım metodu tanımlanmıştır.

Biostimulants have been used in recent years as innovative approaches to stabilize or increase the yield and quality of plants under abiotic stress conditions. Seaweeds, one of the biostimulants, have been used in many cultivated plants and favorable results have been obtained in terms of yield, quality and elemental composition of plant nutrients. Although it is known that safflower plant is sensitive to salt during emergence and germination period, salt and seaweed applications have not been investigated on this plant before. It was aimed to examine the tolerance mechanisms of seaweed applications in safflower plant under salinity stress in terms of some morphological parameters and elemental composition of plant nutrients. The five different doses of salt treatment (0 mM NaCl-distilled water as control, 50 mM, 100 mM, 150 mM, 200 mM) and four different doses of Ascophyllum nodosum seaweed extract (0 g L-1 - distilled water as control, 2 g L-1, 4 g L-1, 6 g L-1) were used as the treatment groups in this study conducted in the climate chamber under controlled conditions. When the figures obtained from safflower plants treated with seaweed in terms of growth parameters were evaluated; root and shoot length, fresh root and shoot weights, dry root and shoot weights generally increased with increasing doses, while relative water content decreased. As salinity stress increased, decreases were generally recorded in all growth parameters obtained. Improved elemental composition of plant nutrients both shoot and root were also observed with seaweed extract applications. In particular, K and Mg in shoot, Ca, Cu and Mg in root increased with increasing seaweed applications. The findings obtained from the study show that seaweed is a promising agricultural application on growth parameters and elemental composition of plant nutrients and reduces the negative effects of salinity stress on safflower plant.