Combined Humic Acid and Lichen-Derived Endophytic Bacteria Application Alleviates Salt Stress-Induced Oxidative Damage in Alfalfa (Medicago sativa L.)

Aytekın Mammadova; Ökkeş Atıcı; Özlem Gülmez

Article Details

Combined Humic Acid and Lichen-Derived Endophytic Bacteria Application Alleviates Salt Stress-Induced Oxidative Damage in Alfalfa (Medicago sativa L.)

Authors:

Aytekın Mammadova | Ökkeş Atıcı | Özlem Gülmez

Publisher:

Bingol University

Main Topics:

Hücre Metabolizması

Journal:

Türk Doğa ve Fen Dergisi Vol.14 Issue 3, pp.172-182

Document Type:

Article

Publication Date:

9/2025

Document Language:

English

Document ID (Org No.):

2001359150

pISSN:

2149-6366

Keywords:

Abstract:

 This study investigates the synergistic effects of leonardite-sourced humic acid HA and a lichen-derived endophytic bacterium Bacillus wiedmannii in mitigating salt stress in alfalfa Medicago sativa L., cv. Konya. Alfalfa seeds were grown in a peat-perlite mix with different combinations of 100 mM NaCl, HA 500 or 1000 mg L-1, and B. wiedmannii. After 35 days, relative water content RWC, ROS H2O2, O₂.-, MDA, antioxidant enzyme activities, and photosynthetic pigments were measured. The salt stress alone reduced RWC, the photosynthetic pigment amount, and the antioxidant enzyme activities, while elevating H2O2 and O2.-, and MDA accumulation. HA or B. wiedmannii Bw individually partially ameliorated these effects, however, the combined HABw treatment under saline conditions especially 1000 mg L¹ HABwNaCl elevated RWC, and reduced ROS and MDA levels close to the control values. In addition, the antioxidant enzyme activities and the photosynthetic pigment contents were enhanced under the combined treatments compared to the salt alone. These results demonstrate a synergistic effect between HA and B. wiedmannii in alleviating salt stress in the alfalfa by enhancing water status, reducing oxidative damage, and activating antioxidant defenses, suggesting that the coapplication of HA and B. wiedmannii is a promising strategy for improving salt tolerance in forage crops.

 This study investigates the synergistic effects of leonardite-sourced humic acid HA and a lichen-derived endophytic bacterium Bacillus wiedmannii in mitigating salt stress in alfalfa Medicago sativa L., cv. Konya. Alfalfa seeds were grown in a peat-perlite mix with different combinations of 100 mM NaCl, HA 500 or 1000 mg L-1, and B. wiedmannii. After 35 days, relative water content RWC, ROS H2O2, O₂.-, MDA, antioxidant enzyme activities, and photosynthetic pigments were measured. The salt stress alone reduced RWC, the photosynthetic pigment amount, and the antioxidant enzyme activities, while elevating H2O2 and O2.-, and MDA accumulation. HA or B. wiedmannii Bw individually partially ameliorated these effects, however, the combined HABw treatment under saline conditions especially 1000 mg L¹ HABwNaCl elevated RWC, and reduced ROS and MDA levels close to the control values. In addition, the antioxidant enzyme activities and the photosynthetic pigment contents were enhanced under the combined treatments compared to the salt alone. These results demonstrate a synergistic effect between HA and B. wiedmannii in alleviating salt stress in the alfalfa by enhancing water status, reducing oxidative damage, and activating antioxidant defenses, suggesting that the coapplication of HA and B. wiedmannii is a promising strategy for improving salt tolerance in forage crops.

 This study investigates the synergistic effects of leonardite-sourced humic acid HA and a lichen-derived endophytic bacterium Bacillus wiedmannii in mitigating salt stress in alfalfa Medicago sativa L., cv. Konya. Alfalfa seeds were grown in a peat-perlite mix with different combinations of 100 mM NaCl, HA 500 or 1000 mg L-1, and B. wiedmannii. After 35 days, relative water content RWC, ROS H2O2, O₂.-, MDA, antioxidant enzyme activities, and photosynthetic pigments were measured. The salt stress alone reduced RWC, the photosynthetic pigment amount, and the antioxidant enzyme activities, while elevating H2O2 and O2.-, and MDA accumulation. HA or B. wiedmannii Bw individually partially ameliorated these effects, however, the combined HABw treatment under saline conditions especially 1000 mg L¹ HABwNaCl elevated RWC, and reduced ROS and MDA levels close to the control values. In addition, the antioxidant enzyme activities and the photosynthetic pigment contents were enhanced under the combined treatments compared to the salt alone. These results demonstrate a synergistic effect between HA and B. wiedmannii in alleviating salt stress in the alfalfa by enhancing water status, reducing oxidative damage, and activating antioxidant defenses, suggesting that the coapplication of HA and B. wiedmannii is a promising strategy for improving salt tolerance in forage crops.

 Bu çalışma, leonardit kaynaklı humik asit HA ile liken kökenli bir endofitik bakteri Bacillus wiedmannii arasındaki sinerjik etkinin, yonca bitkisinde Medicago sativa L., cv. Konya tuz stresini hafifletmedeki rolünü araştırdı. Yonca tohumları, 100 mM NaCl, HA 500 veya 1000 mg L-1 ve B. wiedmanniinin farklı kombinasyonlarını içeren turba-perlit karışımında ekildi. 35 gün sonra, bağıl su içeriği RWC, reaktif oksijen türleri H2O2, O.-, MDA malondialdehit, antioksidan enzim aktiviteleri ve fotosentetik pigment düzeyleri ölçülmüştür. Tuz stresi, tek başına uygulandığında RWC, fotosentetik pigment miktarı ve antioksidan enzim aktivitelerinde azalmaya, H2O2, O.-, ve MDA birikiminde ise artışa neden olmuştur. HA veya B. wiedmannii tek başına bu olumsuz etkileri kısmen hafifletmiştir. Ancak, özellikle 1000 mg L-1 HAB. wiedmanniiNaCl kombinasyonu, RWCyi artırmış ve ROS ile MDA seviyelerini kontrol grubuna yakın düzeylere düşürmüştür. Ayrıca, bu kombine uygulama antioksidan enzim aktiviteleri ile fotosentetik pigment içeriklerini, sadece tuz uygulamasına kıyasla artırmıştır. Bu sonuçlar, HA ile B. wiedmannii arasındaki sinerjik etkinin, su dengesini iyileştirerek, oksidatif zararı azaltarak ve antioksidan savunma sistemlerini aktive ederek tuz stresini hafiflettiğini göstermektedir. Bu nedenle HA ve B. wiedmanniinin birlikte uygulanması, yem bitkilerinde tuz toleransını artırmak için umut verici bir strateji olarak değerlendirilebilir.

Article Details

Combined Humic Acid and Lichen-Derived Endophytic Bacteria Application Alleviates Salt Stress-Induced Oxidative Damage in Alfalfa (Medicago sativa L.)

Authors:

Aytekın Mammadova | Ökkeş Atıcı | Özlem Gülmez

Publisher:

Bingol University

Main Topics:

Hücre Metabolizması

Journal:

Türk Doğa ve Fen Dergisi Vol.14 Issue 3, pp.172-182

Document Type:

Article

Publication Date:

9/2025

Document Language:

English

Document ID (Org No.):

2001359150

pISSN:

2149-6366

Salt stress

Alfalfa

Humic acid

Endophyte

Antioxidant

LichenTuz stresi

Yonca

Humik asit

Endofit

Antioksidan

Liken

Issues

Article Details

Authors: Aytekın Mammadova | Ökkeş Atıcı | Özlem Gülmez

Publisher: Bingol University

Main Topics: Hücre Metabolizması

Journal: Türk Doğa ve Fen Dergisi Vol.14 Issue 3, pp.172-182

Document Type: Article

Publication Date: 9/2025

Document Language: English

Document ID (Org No.): 2001359150

pISSN: 2149-6366

Issues

Authors:

Aytekın Mammadova | Ökkeş Atıcı | Özlem Gülmez

Publisher:

Bingol University

Main Topics:

Hücre Metabolizması

Journal:

Türk Doğa ve Fen Dergisi Vol.14 Issue 3, pp.172-182

Document Type:

Article

Publication Date:

9/2025

Document Language:

English

Document ID (Org No.):

2001359150

pISSN:

2149-6366