Effects on Water Stress on Daily Stomatal Conductivity of Stevia rebaudiana

Stevia rebaudiana (Bertoni), an herbaceous perennial plant belong to Asteraceae family, is one of the important source of natural sweetening agents with non-calorie that can be used as an alternative to artificial sweeteners. Plant originating in Paraguay and the south-west of Brazil, have some usage possibilities in many sector and can accumulate glycosides which tastes about 300 times sweeter than sugar cane. The previous studies have shown that stevia plant is affected by water stress. In case of water stress, the plants close their stomata and reduced the rate of transpiration. In this study which was carried out at the Akdeniz University in 2016 under a rainout shelter, it was aimed to determine changes in daily stomatal conductance before and after irrigation (T) for consecutive 15 days. In this scope, stevia plants were grown under 6 different irrigation regimes (I) including a control (I100), plants irrigated with 100% restitution of water consumption and additionally 120% (I120), 80% (I80), 60% (I60), 40% (I40) and 20% (I20) of the control treatment and 2 nitrogen (N) levels including zero N (control, N0) and recommended nitrogen level of 10 kg N/da (N10) in a split plot experimental design with three replicates. Irrigation schedule was based on A-Class evaporation pan and soil moisture level. As a result of study, it was determined that stomatal conductivities were decreased with increasing water stress at each N levels.