%0 Journal Article %T Effect of Heat Stress Duration on Growth, Flowering and Electrolyte Leakage in Four Cultivars of Calendula officinalis %A Nazdar, Tayebeh %A Tehranifar, Ali %A Nemati, Seyyed Hossein %A Samiei, Leila %J Journal of Ornamental plants %@ 2251-6433 %D 2017