Determination of salt tolerance in petunia at seed germination and seedling early growth stages

Identification of salt tolerant plant species and cultivars is important for preserving and developing urban landscape and increasing water use efficiency in these plantings. Petunia (Petunia hybrida) is of the most important outdoor plants; therefore, identification of salt tolerant petunia cultivars is critical. Screening during seed germination and seedling early growth is considered as a rapid and accurate approach for determining plant salt tolerance. In this study, the effects of sodium chloride derived salt stress (0, 25 and 50 mM NaCl in the Hoagland‟s nutrient solution) were investigated on germination and early growth of 15 cultivars (five Persian, five English and five Dutch cultivars) as a factorial experiment based on a completely randomized design with three replications and 20 seeds per replicate. Seeds were grown in trays containing uniform media of perlite, cocopeat, and sand were irrigated with different concentrations of NaCl in the Hoagland‟s nutrition solution. Number of germinated seeds was recorded every day and 60 days after seed cultivation, plant growth indices including fresh and dry mass of stem, leaves, and roots shoot: root ratio, mean leaf area, number of damaged leaves, relative water content of the plants, and membrane stability index were recorded. Salt stress reduced seed germination rate and final seed germination percentage and reduced shoot and root growth of all cultivars. Furthermore, salt stress reduced the membrane stability index and increased the water content of the plants. Under salt stress, White Calibrachoa (Persian) and Prism White (English) cultivars represented lower growth limitation and damage than other cultivars; therefore, these cultivars were introduced as the most salt tolerant and Prism Ruby and Prism Red cultivars were introduced as the most sensitive cultivars.

کلیدواژه ها:

Membrane stability index ، Osmotic stress ، Seed germination ، Germination rate ، Plant growth ، Petunia hybrida