A plant-based biostimulant approach to improve salt stress tolerance in tomato: The role of Hypericum heterophyllum Vent. extract

Abstract

Salt stress severely limits seed germination and early seedling establishment in tomato. Plant-derived extracts have recently attracted attention as eco-friendly biostimulants capable of enhancing stress tolerance. The present study investigated the effects of different concentrations of Hypericum heterophyllum whole-plant extract on seed germination, seedling growth, and changes in physiological and biochemical parameters in tomato under salt stress. Tomato seeds were primed with aqueous H. heterophyllum extract at 0.25, 0.5, 1, and 2% (w/v) and subsequently exposed to NaCl-induced (200 mM) salinity stress. Germination percentage, mean germination time, root and shoot length (at early and late seedling stages), membrane damage, total chlorophyll content, and total flavonoid and phenolic contents in tomato leaves were evaluated. Salt stress markedly reduced germination and seedling growth, whereas H. heterophyllum extract treatments significantly alleviated these inhibitory effects in a concentration-dependent manner. The 0.5% and 1% extract concentrations were the most effective in improving germination performance and seedling growth under salt stress. These treatments also decreased membrane damage and increased total chlorophyll content. Moreover, increasing extract concentration led to higher total phenolic and flavonoid contents under salt stress. Overall, these findings suggest that H. heterophyllum extract has strong potential as a natural biostimulant and could be considered a promising, sustainable strategy to enhance salt stress tolerance and improve crop establishment in agricultural production.

Keywords

• Hypericum heterophyllum
• Salt stress
• Tomato
• Seed priming
• Biostimulant.

Domateste tuz stresi toleransını artırmak için bitki bazlı bir biyostimülan yaklaşımı: Hypericum heterophyllum Vent. özütünün rolü

Abstract

Tuz stresi, domateste tohum çimlenmesini ve erken fide oluşumunu ciddi şekilde sınırlandırmaktadır. Bitki kaynaklı özler, son zamanlarda stres toleransını artırabilen çevre dostu biyostimülanlar olarak dikkat çekmektedir. Bu çalışma, Hypericum heterophyllum bitkisinin tamamının farklı konsantrasyonlarının, tuz stresi koşulları altında domateste tohum çimlenmesi, fide büyümesi ve bazı fizyolojik ve biyokimyasal parametrelerdeki değişiklikler üzerindeki etkilerini araştırmıştır. Domates tohumları, %0,25, %0,5, %1 ve %2 (w/v) oranlarında sulu H. heterophyllum özü ile ön işleme tabi tutulmuş ve daha sonra NaCl kaynaklı (200 mM) tuz stresine maruz bırakılmıştır. Çimlenme yüzdesi, ortalama çimlenme süresi, kök ve sürgün uzunluğu (erken ve geç fide aşamalarında), membran hasarı, toplam klorofil içeriği ve domates yapraklarındaki toplam flavonoid ve fenolik içerik değerlendirilmiştir. Tuz stresi, çimlenmeyi ve fide büyümesini belirgin şekilde azaltırken, H. heterophyllum özü uygulamaları, bu engelleyici etkileri konsantrasyona bağlı olarak önemli ölçüde hafifletmiştir. %0,5 ve %1'lik ekstrakt konsantrasyonları, tuz stresi altında çimlenme performansını ve fide büyümesini iyileştirmede en etkili olanlardı. Bu uygulamalar ayrıca membran hasarını azalttı ve toplam klorofil içeriğini artırdı. Dahası, ekstrakt konsantrasyonunun artması, tuz stresi altında daha yüksek toplam fenolik ve flavonoid içeriğine yol açtı. Genel olarak, bu bulgular H. heterophyllum ekstraktının doğal bir biyostimülan olarak güçlü bir potansiyele sahip olduğunu ve tarımsal üretimde tuz stresi toleransını artırmak ve mahsul gelişimini iyileştirmek için umut vadeden, sürdürülebilir bir strateji olarak değerlendirilebileceğini göstermektedir.

Keywords

• Hypericum heterophyllum
• Tuz stresi
• Domates
• Tohum ön işlem
• Biyostimülan.

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