Studies on the effects of heavy metal stress on photosynthesis and physiology of Dian Hong rose

Dian Hong rose is the largest edible rose variety in Yunnan, rich in glutathione, in addition to ornamental value, is also an important raw material in the food flavor industry. In recent years, due to the serious soil pollution in China, there are few reports on the physiological and biochemical reactions of rose under heavy metal stress, and the heavy metal tolerance of Dian Hong rose remains to be studied. In this experiment, the photosynthetic and physiological effects of chromium and cadmium on Dian Hong rose were investigated by single stress treatment (single stress treatment refers to the addition of only one heavy metal to the treatment). The study results demonstrated that as the treatment concentrations of chromium (Cr) and cadmium (Cd) increased, the content of soluble sugars, soluble proteins, malondialdehyde, peroxidase, and catalase in the leaves correspondingly augmented. The pigment content of leaves decreased with the increase of treatment concentration.The daily variation trends of net photosynthetic rate (Pn) and transpiration rate (Tr) of leaves were similar, showing A trend of first increasing and then decreasing. When the concentration of Cr ion in treatment A exceeded 300 mg•Kg^− 1, and the concentration of Cd in treatment B exceeded 50 mg•Kg^− 1, the net photosynthetic rate of leaves was worse than that in control group, and the net photosynthetic rate gradually decreased with the increase of stress concentration. The above studies indicated that the plant damage caused by metabolic imbalance could be reduced by increasing osmotic regulatory substances in leaves and inducing active oxygen scavenging system when the rose was stressed by heavy metals. In a certain concentration range, its growth trend was better than that of the control group, which proved that the Dian Hong rose had a certain degree of heavy metal stress tolerance.