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The changes and distribution of non-structural carbohydrate (NSC, including soluble sugar and starch) content in different organs of one-year-old Caryopteris mongolica seedlings were investigated under suitable water condition (CK), slow-dying drought stress, and fast-dying drought stress. There was no significant difference in soluble sugar content of all organs between slow-dying drought stress and CK. With the extended duration of drought, the soluble sugar content in stem increased firstly and then decreased, while starch and NSC contents decreased. The soluble sugar content in coarse roots decreased, while starch and NSC contents increased. The soluble sugar content in leaves increased, while starch and NSC contents of leaves decreased. The NSC content of leaves, stems, coarse roots and fine roots were 6.2%, 7.8%, 8.3% and 7.4% at the death time (80 days), respectively. Under fast-dying drought stress, soluble sugar content in all organs was higher than that in CK, while starch and NSC contents were lower than that in CK. With the increasing time, soluble sugar content of roots decreased, while starch and NSC contents increased. The soluble sugar, starch and NSC contents in stems increased. The soluble sugar content of leaves increased, while starch and NSC contents decreased. The NSC content of leaves, stems, coarse roots and fine roots were 5.9%, 6.6%, 8.9% and 7.7% at lethal time (30 days), respectively. Under different drought stress, non-structural carbohydrates among different organs of C. mongolica seedlings showed different dynamics. Under slow-dying drought stress, NSC gave priority to allocate energy for maintaining physiological metabolism of organs. Under fast-dying drought stress, NSC mainly maintained plant metabolism in the form of soluble sugar, regulated osmotic potential, promoted water absorption, and coped with drastic drought stress.

In order to improve the protection system to reduce the damage of biodiversity and protect broad-leaved Korean pine mixed forest, 64 forest farms from 6 Forestry Bureaus around Changbai Mountains Nature Reserve were investigated and analyzed. A total of 41 plants were selected as key protected plants, and felling area, cropland, mining area, highway, railway and residential area were considered as the disturbance factors. GAP and GIS spatial analysis were used to draw the indicator plant and disturbance intensity distribution maps. The results showed that the indicator species distribution was uneven. The indicator plant enrichment regions were located on the north western and southern slopes centered with Shengli and Lenggouzi forest farms of Quanyang County, respectively, and single distributions of the endemic plants were found in Baoshan, Henshan, Lenggouzi and Heishan forest farms. The different disturbance severities were observed in the different forest farms, among which the north part in Lushuihe and Baihe forest farms were severely disrupted. Two ecologically critical areas, Quanyang-Lushuihe-Baihe on the north slope of Changbai Mountains and the east part of Changbai County on the south slope, were determined based on the comprehensive analysis.