During somatic embryogenesis of Pinus koraiensis, the ability of the embryogenic callus to produce embryos gradually decreases with long-term proliferative culture, which seriously affects large-scale application of this technology. In this study, embryogenic calli of Korean pine 1–100 cell line were used as materials. It was found that in the 7-day subculture cycle of embryogenic calli the somatic embryogenic potential of Korean pine remained for the longer time. In comparison with a subculture cycle of 14 days, indoleacetic acid (IAA), soluble sugar, and starch contents in embryogenic callus were higher with a subculture cycle of 7 days, while hydrogen peroxide (H2O2) content showed the opposite trend. Further, low levels of endogenous abscisic acid (ABA) and high levels of IAA could inhibit somatic embryogenesis of P. koraiensis calli. Among different carbon sources, maltose produced more storage materials and higher superoxide dismutase (SOD) and catalase (CAT) activities than sucrose, which was conducive to cell differentiation and somatic embryogenesis. The results revealed the physiological characteristics of the loss of embryogenic capacity of Korean pine embryogenic callus and provided a basis for the long-term maintenance of its somatic embryogenic capacity.

Different treatments of logging residues can impact on the forest soil carbon pool, but the short-term effects are still unclear. This study aimed to the relationship between the changes of the addition of logging residues and different tree species soil organic carbon content and basic soil parameters. The experimental site was located in Harbin, China, and four logging residue addition levels were set under six forest types, converted to carbon added as 0, 250 (low carbon addition, LC), 500 (medium carbon addition, MC) and 1000 (high carbon addition, HC) g/m2. In the short-term (five months), the logging residues partially decomposed, but the effect on basic soil parameters was small. Soil organic carbon, microbial carbon, and dissolved organic carbon increased significantly in the 0–10 cm soil layer for some tree species, and not significantly in the 10 –20 cm soil layer. There is no consistent relationship between the addition of logging residues and soil parameters under different tree species. That adding logging residues could increase soil carbon pool, there were treespeciesspecific differences in the dynamics of soil processes.