Effect of Calcium Nitrate Applications on Plant Development and Some Physiological Characteristics of Sunflower Seedlings Grown Under Drought Conditions

Drought stress is one of the abiotic stresses that negatively affects plant growth, development and product yield. In recent years, nutrient solution applications to leaves have been frequently used to reduce the negative effects of drought stress. This study was conducted in 2024 at the Atatürk University, Plant Production Application and Research Center to determine the effect of calcium nitrate applications during the seedling period on the growth and some physiological characteristics of sunflower (Helianthus annuus L.) grown under drought stress. The study was based on two-factor completely randomized experimental design with three irrigation levels [full irrigation (100% (I0), 70% (I1) and 40% (I2) of field capacity), two Ca(NO3)2 concentrations (15 mM and 30 mM)]. The study was carried out as a pot trial based on this experimental design. At the end of the trial period, plant growth parameters and some physiological measurements and analyzes were performed on sunflower plants and the differences between the treatments were evaluated. According to the research findings, significant differences were observed between the different treatments and irrigation levels. The application of Ca(NO3)2 significantly influenced plant growth parameters (such as plant height, stem diameter, fresh and dry weight) and physiological parameters [such as tissue relative water content (RWC)] in sunflower grown under varying irrigation levels. At the end of the study, it was determined that dry conditions negatively affected plant growth in sunflowers and reduced the RWC value. In conclusion; calcium nitrate applications reduced this negative effect of drought compared to the control application. It can be said that especially the results obtained from the application of 15 Mm CaN at 70% (I1) irrigation level are relatively less affected by drought.