The amount of secondary metabolites can be increased with different elicitor applications in vitro. It has been determined that zinc sulphate significantly increases the amount of capsaicin in the cell culture of red hot pepper. It is important to determine how the metal applied as elicitor will have an effect on plant metabolism. In the study, it was aimed to determine the effects of zinc sulphate (ZnSO4) applied to the cell suspension cultures of pepper seeds at different concentrations (0.1 M, 0.2 M, 0.4 M) and for periods (24, 48, 72 hours) on the total protein and phenolic substance amounts, and superoxide dismutase-peroxidase enzyme activities of pepper calluses. It was observed that the amount of protein increased, superoxide dismutase and peroxidase enzyme activities decreased, and the total amount of phenolic substance increased especially in 72 hours of treatment where zinc was applied as elicitor. These results show that ZnSO4 can be used as an abiotic elicitor in plant cell culture media.

Drought stress is one of the most serious abiotic stresses that cause a reduction in plant growth, development and yield in the world. The aim of this study is to reveal the morphological, physiological and biochemical responses of the Demre pepper variety and nine different pepper genotypes against drought stress. Pepper seeds were planted into trays containing peat: perlite (2: 1) mixture. Then, seedlings having two leaves were transferred to plastic pots containing mixture of peat:perlite (2:1) mixture. Drought stress application was started when the plants have four leaves. The control plants were irrigated with nutrition solution. Genotypes were classified according to the severity of leaf damage symptoms by using 0-5 scale. In addition, shoot fresh and dry weight, plant height, stem diameter, leaf number, leaf area, relative water content (RWC), membrane injury index (MII), potassium (K) and calcium (Ca) concentration of shoot, malondialdehyde content (MDA), total chlorophyll and carotenoid, total flavonoid and phenolic content, anitoxidative enzyme activities (superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), ascorbate peroxidase (APX)) were also determined. As a result of the study, it was determined that drought had negative effect in terms of morphological and physiological parameters, and this effect revealed differences among genotypes. While drought stress increased MDA and antioxidative enzyme activity, BIB-6 and BIB-8 genotypes were found to be the most tolerant genotypes among the genotypes examined.

Arjinin, bitkilerde stres metabolizmasında yer alan çeşitli metabolitlerin öncülüğünü yapan bir aminoasit olmasının yanı sıra, bitkilerin çevresel streslere yanıtını modüle edebilen bir sinyal molekülüdür. Tuzluluk stresi, özellikle mısır (Zea mays) yetiştiriciliğinde, mahsul verimliliğini artırma açısından önemli bir zorluk oluşturmaktadır. Bu çalışma, L-argininin (L-arg) lipid peroksidasyonunu, bazı antioksidan enzim aktivitelerini ve bu enzimlerin gen ifade seviyelerini modüle ederek tuz stresinin neden olduğu oksidatif hasarı hafifletmedeki potansiyel rolünü araştırmaktadır. Bulgularımız, 200 mM tuz stresi uygulamasında H2O2 ve MDA seviyelerinin arttığını, ancak 1,5 ve 3 mM L-arg uygulamalarının bu seviyeleri azalttığını göstermektedir. Ayrıca çalışmamızda, süperoksit dismutaz (SOD), peroksidaz (POD) ve askorbat peroksidaz (APX) aktiviteleri ile ZmSOD, ZmPOD ve ZmAPX gen ifade seviyelerinin tuz stresi altında giderek arttığı, ancak L-arg’ın bu parametreleri arttırmada daha etkili olduğu belirlenmiştir. En yüksek artışlar SOD enzim aktivitesinde ve ZmSOD gen ifadesinde gözlemlenmiştir. Bu araştırma, tuz stresinde bazı moleküler ve biyokimyasal yanıtların anlaşılmasını derinleştirerek, L-arg uygulamasının bitkilerin çevresel zorluklara karşı direncini artırmada kritik bilgiler sunabileceği önemli bir literatür kaynağıdır.