The Effect of Pre-Germination Treatment with L-Proline on the Germination Dynamics of Forage Soybean Seeds Under Salt Stress

Abstract

The present study was conducted with the objective of evaluating the effects of pre-sowing L-proline (LP) applications on the germination dynamics of forage soybean seeds under salt stress conditions. The seeds used in the study were soaked in LP solutions at concentrations of 0, 50, 100, and 150 mg L-1 for 24 hours at 15ºC. Germination tests were then conducted at NaCl concentrations of 0, 50, 100, and 150 mM. The study was conducted under controlled conditions in accordance with the principles established by ISTA. The experiment was conducted in four replications. The study evaluated the following parameters: total germinated seeds (TGS), germination rate (GR), germination speed index (GSI), average germination time (AGT), germination rate coefficient (GRC), and sensitivity index (SI). The results showed that LP treatments alone had no significant effect on the germination parameters examined. In contrast, it was found that increasing NaCl concentrations significantly reduced GSI and GRC values, while prolonging AGT. The sensitivity index increased with increasing salt concentrations, and the LP x NaCl interaction was found to be significant for this parameter. The highest SI value (1.504) was observed in the combination of 150 mg L-1 LP and 150 mM NaCl. This indicates that high LP doses may exacerbate rather than alleviate stress effects under severe salinity conditions. In general, while LP had no significant effect on overall germination rates, increasing NaCl concentrations severely disrupted germination dynamics. It has been concluded that the effects of amino acid applications depend largely on dosage, stress levels, and their interactions. These findings underscore the importance of optimizing germination conditions and indicate the need to investigate alternative amino acid types, application methods, and dosages to enhance the stress tolerance of forage soybean plants during the germination period.

Keywords

• Abiotic stress
• amino acid
• forage soybean
• germination
• NaCl

Tuz Stresi Altındaki Yemlik Soya Fasulyesi Tohumlarının Çimlenme Dinamikleri Üzerine L-Prolin ile Çimlenme Öncesi İşlemin Etkisi

Abstract

Soya üretimi çimlenme ve erken fide gelişimi aşamalarında tuz stresi nedeniyle sıklıkla kısıtlanmaktadır. Bu çalışma, tuz stresi koşulları altında yemlik soya fasulyesi tohumlarının çimlenme dinamikleri üzerine ekim öncesi L-prolin (LP) uygulamalarının etkilerini değerlendirmek amacıyla gerçekleştirilmiştir. Çalışmada kullanılan tohumlar, 15ºC'de 24 saat boyunca 0, 50, 100 ve 150 mg L-1 konsantrasyonlarında LP çözeltilerinde ıslatılmıştır. Ardından, 0, 50, 100 ve 150 mM NaCl konsantrasyonlarında çimlenme testleri yapılmıştır. Çalışma, ISTA tarafından belirlenen ilkelere uygun olarak kontrollü koşullar altında gerçekleştirilmiştir. Deney dört tekerrürlü olarak gerçekleştirilmiştir. Çalışmada; toplam çimlenen tohum sayısı (ÇTS), çimlenme oranı (ÇO), çimlenme hızı indeksi (ÇHI), ortalama çimlenme süresi (OÇT), çimlenme oranı katsayısı (ÇOK) ve duyarlılık indeksi (DI) parametreleri değerlendirilmiştir. Sonuçlar, LP uygulamalarının tek başına incelenen çimlenme parametrelerini olumsuz etkilemiştir. Buna karşılık, artan NaCl konsantrasyonlarının ÇHI ve ÇOK değerlerini önemli ölçüde düşürdüğü, ÇS süresini ise uzattığı saptanmıştır. DI, tuz konsantrasyonlarının artmasıyla birlikte yükselmiş ve bu parametre açısından LP ile NaCl arasındaki etkileşimin anlamlı olduğu görülmüştür. En yüksek SI değeri (1,504), 150 mg L-1 LP ve 150 mM NaCl kombinasyonunda gözlemlenmiştir. Bu, yüksek LP dozlarının şiddetli tuzluluk koşulları altında stres etkilerini hafifletmek yerine daha da şiddetlendirebileceğini göstermektedir. Genel olarak, LP'nin genel çimlenme oranları üzerinde önemli bir etkisi olmamasına rağmen, artan NaCl konsantrasyonları çimlenme dinamiklerini ciddi şekilde bozmuştur. Amino asit uygulamalarının etkilerinin büyük ölçüde doza, stres seviyelerine ve bunların etkileşimlerine bağlı olduğu sonucuna varılmıştır. Bu bulgular, çimlenme koşullarının optimize edilmesinin önemini vurgulamakta ve çimlenme döneminde yemlik soya fasulyesi bitkilerinin stres toleransını artırmak için alternatif amino asit türleri, uygulama yöntemleri ve dozajlarının araştırılması gerektiğini göstermektedir.

Keywords

• Anahtar Kelimeler: Abiyotik stres
• amino asit
• yemlik soya fasulyesi
• çimlenme
• NaCl

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