Responses of Root Border Cells of Cucumber (Cucumis sativus) and Pumpkin (Cucurbita moschata × Cucurbita maxima) Seedlings to Cinnamic Acid Stress

摘要

In the present study, effects of cinnamic acid (CA) concentrations on root border cells (RBCs) of the seedlings of cucumber and pumpkin were investigated. Two different concentrations of CA along with a control i.e., 0, 0.125 and 0.250 mmol L -1 were used. Their effects on numbers, survival rates, mucigel thicknesses, apoptosis rates of RBCs and the root activities were monitored. Survival rates of RBCs and root activities of both cucumber and pumpkin were decreased at 0.125 and 0.250 mmol L -1 CA. These inhibitory effects were more significant on cucumber. However, the mucigel thicknesses and apoptosis rates in RBCs of both cucumber and pumpkin were increased at 0.125 and 0.250 mmol L -1 concentrations of CA. In comparison with cucumber, greater mucigel thickness and lower apoptosis rates of RBCs were detected in pumpkin. At a concentration of 0.250 mmol L -1 CA, while RBCs attached to the root tips, root activities decreased by 18.8% in cucumber. This change was insignificant in pumpkin. After removing the RBCs, the root activities of both cucumber and pumpkin were sharply inhibited by 0.250 mmol L -1 CA. This inhibition was higher in cucumber than pumpkin. It has indicated that, RBCs could increase plant’s resistance to CA stress, which was characterized by low apoptosis rate and thick mucigel. The resistance of RBCs in pumpkin to CA stress was stronger than RBCs of cucumber.