Respiration Rate and Endogenous Hormone Levels in Relation to the Flower Development of Tree Peonies Respiration Rate and Endogenous Hormone Levels in Relation to the Flower Development of Tree Peonies Difference of Endopeptidase Activity in Petals between Two Cut Rose Cultivars with Diferent Tolerance to W ater Deficit Stress during Flower Opening and Senescence Difference of Endopeptidase Activity in Petals between Two Cut Rose Cultivars with Diferent Tolerance to W ater Deficit Stress during Flower Opening and Senescence Effects of Exogenous Abscisic Acid,Nitric Oxide and Hydrogen Peroxide on Stomatal Movement in Petals and Leaves of Zephyranthes candida