Effects of different healing agents on acclimatization success of in vitro rooted Garnem (Prunus dulcis × Prunus persica) rootstock

Continuing productivity of the acclimatization stage of plantlets means successful micropropagation. Due to the free water and high humidity in the culture container environment, poorly developed cuticle results in rapid water loss and drying of plantlets with watery stems and leaves, incomplete stomata, and large intercellular space. When plantlets are exposed to an environmental condition different from the culture medium, problems, such as rapid water loss and drying, may be encountered, and the survival rate of plantlets in vitro may be reduced. The aim of this study was to reduce the stress factors that occur during the acclimatization phase. For this reason, various healing agents have been used. Some of these compounds are ascorbic acid (AsA), salicylic acid (SA), and sodium nitroprusside (SNP). In the study, the response of AsA (100.0 and 200.0 mg L⁻¹), SA (100.0 and 200.0 mg L⁻¹), and SNP (100.0 and 200.0 µM) applications on growth parameters (survival rate (%), node count (pieces per plant), count of leaves (pieces per plant), shoot length (mm), and shoot diameter (mm)) and physiological variable (Soil Plant Analysis Development (SPAD)) were examined. The AsA100 (100.0 mg L⁻¹ ascorbic acid), AsA200 (200.0 mg L⁻¹ ascorbic acid), and SNP100 (100.0 µM sodium nitroprusside) applications resulted in an improvement in node count, leaf count per plant, shoot length, and shoot diameter parameters. The highest shoot length (60.50 ± 7.81 mm) and node count (16.83 ± 1.15 pieces per plantlet) were achieved with the AsA100 application. The maximum stem diameter (2.31 ± 0.37 mm) was determined with the SNP100 application. There were no statistically significant differences found in the survival rate, leaf count, and SPAD parameter. The current study determined that AsA, SA, and SNP applications were effective in regulating several growth parameters in Garnem plantlets and in reducing acclimation stress thereby facilitating adaptation to external conditions.