Effects of drought stress on growth, nutrition and physiological characteristics of Platycladus orientalis container and bareroot seedlings.

Taking Platycladus orientalis as study materials, this paper investigates how different treatments of drought stress (light, moderate, severe and control) impact the growth, nutrition and physiological characteristics of container and bareroot seedlings by applying the pot method. Results showed that antioxidant enzyme activity, osmotic adjustment substance, and lipid peroxidation products were becoming higher along with drought stress. Under drought stress conditions, antioxidant enzyme activities of container seedlings were significantly higher than those of bareroot ones. However, osmotic adjustment substance and lipid peroxidation products in bareroot seedlings were higher than those in container ones. No significant difference was observed between container and bareroot seedlings under light drought stress. Compared with the irrigated control, the relative water content of P. orientalis container seedlings decreased by 10.43%, as well as that of bareroot ones decreased by 18.36%. However, the relative electric conductance of container and bareroot seedlings increased by 28.87% and 43.49%, respectively, indicative of less change of container seedlings than that of the bareroot ones. Compared with P. orientalis bareroot seedlings, container seedlings had higher dry matter accumulation. Additionally, an increasing effect of container seedlings on dry matter accumulation was obtained along with the increasing drought intensity. Although no significant effect of drought stress on shoot nutrition contents was observed, potassium content of root was significantly increased. Whatever the water conditions, nutrition accumulations of P. orientalis container seedlings were significantly higher than those of bareroot ones. Additionally, an increasing difference between container and bareroot seedlings was observed along with the increasing drought intensity. As a result, container seedlings had higher regulating capacity of antioxidant enzyme, and could reduce the accumulation of lipid peroxidation products in compared with bareroot seedlings. This study also demonstrated the benefits of container seedlings on dry matter accumulation and nutrition absorption, indicative of the better drought resistance of P. orientalis container seedlings than those of bareroot ones.