PEG 6000 Kuraklık Stresi Altında Phaseolus vulgaris Genotiplerinin Çimlenmesi ve Dayanıklılığı

Abstract

Bu çalışma, PEG 6000 ile indüklenen osmotik kuraklık stresi altında farklı fasulye (Phaseolus vulgaris L.) genotiplerinin çimlenme aşamasındaki performansını ve tolerans düzeylerini belirlemeyi amaçlamıştır. Küresel kuraklık riskinin arttığı bir bağlamda, erken fide gelişim aşamasındaki stres toleransını aydınlatmak, sürdürülebilir üretim ve ıslah stratejileri açısından hayati önem taşımaktadır. Bulgular, artan osmotik stres seviyelerinin plumula ve radikula uzunluklarını önemli ölçüde azalttığını göstermiştir; buna bağlı olarak, hipokotil, plumula ve radikulanın taze ve kuru ağırlıklarında belirgin düşüşler gözlemlenmiştir. Özellikle şiddetli stres koşullarında (−5 bar), tüm genotiplerde sürgün ve kök gelişimi önemli ölçüde baskılanmış ve biyokütle birikimi belirgin şekilde kısıtlanmıştır. Bununla birlikte, kuraklık tepkisi açısından genotipler arasında önemli farklılıklar tespit edilmiştir. KKF-BY-15-28 genotipi, çimlenme aşamasında kök ve sürgün büyümesini daha etkili bir şekilde sürdürerek daha toleranslı bir profil sergilerken, Karaman-2016 genotipi hem uzunluk hem de biyokütle parametrelerinde belirgin azalmalar göstererek kuraklık stresine karşı yüksek duyarlılık sergilemiştir. Berrak ve KKF-BY-15-8 genotipleri orta düzeyde performans sergilemiştir; ancak stres şiddeti arttıkça büyüme parametrelerinde önemli düşüşler gözlemlenmiştir. Sonuç olarak, çimlenme aşamasında ölçülen morfolojik ve biyokütle bazlı parametrelerin güvenilir ve pratik göstergeler olduğu ortaya konmuştur.

Keywords

• Biyokütle dağılımı
• ozmotik stres toleransı
• kök-gövde büyüme dinamikleri
• tohum canlılığı

Germination and Tolerance of Phaseolus vulgaris Genotypes under PEG 6000 Drought Stress

Abstract

This study aimed to determine the germination-stage performance and tolerance levels of different common bean (Phaseolus vulgaris L.) genotypes under osmotic drought stress induced by PEG 6000. In the context of the increasing global drought risk, elucidating stress tolerance during the early seedling developmental stage is of critical importance for sustainable production and breeding strategies. The findings demonstrated that increasing osmotic stress levels significantly reduced plumule and radicle lengths; correspondingly, marked decreases were observed in the fresh and dry weights of the hypocotyl, plumule, and radicle. Particularly under severe stress conditions (−5 bar), shoot and root development were substantially suppressed across all genotypes, and biomass accumulation was markedly constrained. Nevertheless, significant differences were detected among genotypes in terms of drought response. The KKF-BY-15-28 genotype exhibited a relatively more tolerant profile by sustaining root and shoot growth more effectively during the germination stage, whereas the Karaman-2016 genotype showed pronounced reductions in both length and biomass parameters, indicating high sensitivity to drought stress. The Berrak and KKF-BY-15-8 genotypes displayed intermediate performance; however, substantial declines in growth parameters were observed as stress severity increased. In conclusion, morphological and biomass-based parameters measured at the germination stage were demonstrated to be reliable and practical indicators for the early assessment of drought tolerance in common bean. This approach may be an effective tool for preliminary selection of drought-tolerant genotypes.

Keywords

• Biomass allocation
• osmotic stress tolerance
• root–shoot growth dynamics
• seed vigor

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