Effects of pre-harvest applications of different source of calcium on the cell wall fractions and stem bending disorder of Gerbera (Gerbera jamesonii L.) cultivar flowers

Abstract

Gerbera flower belongs to the composite family and is one of the top five cut flowers in the world in terms of production and consumption, which has a great economic value in the international flowering industry. This study was designed to evaluate whether calcium pre-harvest application, provided through 0, 0.5, 1 and 1.5% of calcium chloride (CaCl2) and calcium nitrate (CaNO3), could extend the day of stem bending of gerbera cut flower. In the present study, we used two gerbera cultivars ‘Intense’ and ‘Rosaline’ as resistant and sensitive to stem bending, respectively. For evaluation of associated traits with stem bending, the produced flowers were kept in a vase solution containing 200 mg/L hydroxyquinoline with temperature conditions of 20°C. The results showed that day of stem bending of flowers extended 9.62 and 10.37 days by application of 1% CaCl2 for ‘Rosaline’ and ‘Intense’ respectively. All treatments were effective in the increasing relative water content of flower due to increase water uptake. The results also revealed that the calcium pretreatment delayed flowers senescence and increased antioxidant enzyme activity. Application of calcium resulted in an increase in membrane stability index in the cut flowers of both cultivars, providing evidence for delay of senescence in calcium-treated cut flowers. Also, results showed that calcium application significantly increased lignin, cellulose and hemicellulose content of both cultivars. The maximum and the minimum lignin and cellulose content were observed in resistant and sensitive cultivars, respectively. In general, pre-harvest application of calcium (especially 1% CaCl2) with increasing of antioxidant enzyme activity and stem lignification led to decreasing of stem bending disorder in both cultivars.