Effect of Sodium Lignate Immersion on seed Vigor and Physiological Characteristics of Platycladus orientalis seeds

To investigate the effects of sodium lignosulfonate (BCOL) seed soaking on seed vigor and physiological characteristics of Platycladus orientalis, artificial aging was used to prepare P. orientalis seeds with different vigor levels: high vigor (unaged), medium vigor (aged for 4 d), and low vigor (aged for 7 d). The seeds were soaked in BCOL solutions at concentrations of 0, 25, 50, 100, and 200 mg/L, followed by the determination of seed germination indices, seedling growth indices, and physiological indices including malondialdehyde (MDA) content, soluble protein (SP) content, soluble sugar (SS) content, proline (Pro) content, relative electrical conductivity (REC) of exudate, peroxidase (POD) activity, and catalase (CAT) activity. Correlation analysis and principal component analysis were performed on the above indices. The results showed that seed soaking with appropriate concentrations of BCOL could inhibit the increase in REC and MDA content of P. orientalis seeds, promote the enhancement of POD and CAT activities, and facilitate the accumulation of SP, SS, and Pro. Principal component analysis indicated that for high and medium vigor P. orientalis seeds, treatment with 50 mg/L BCOL exhibited the optimal performance in related indices; while for low vigor seeds, the optimal treatment was 100 mg/L BCOL.