[Dynamic changes of dominant tree species in broad-leaved Korean pine forest at different succession stages in Changbai Mountains].

Taking the broad-leaved Korean pine forest stands at four different succession stages after clear-cutting in Changbai Mountains as test objects, this paper studied the change characteristics of community composition and dominant species. The tree species richness, Shannon diversity index, and Simpson dominance index at different succession stages had less change, but the evenness and abundance changed greatly. As succession progressed, the community composition changed constantly, i.e., species number decreased, while the basal area sum and the maximum importance value of dominant tree species increased, suggesting that the dominance of dominant species was continuously improved with succession. In the succession process of broad-leaved Korean pine forest in Changbai Mountains, Betula platyphylla, Populus davidiana, Phellodendron amurense, Ulmus japonica, and other intolerant or semi-intolerant tree species decreased, while Tilia amurensis, Fraxinus mandshurica, Pinus koraiensis, Acer mono, and other shade-tolerant species increased.

Design, synthesis, and bioactivities screening of a diaryl ketone-inspired pesticide molecular library as derived from natural products.

Three natural products, 1,5-diphenylpentan-1-one, 1,5-diphenylpent-2-en-1-one, and 3-hydroxy-1,5-diphenylpentan-1-one, with good insecticidal activities were extracted from Stellera chamaejasme L. Based on their shared diaryl ketone moiety as 'pharmacophores', a series of diaryl ketones were synthesized and tested for insecticidal activity, acetylcholinesterase inhibitory activity, and antifungal activity. All synthesized compounds showed poor insecticidal and acetylcholinesterase inhibitory activities. Compound III with a furyl ring showed strong activities against plant pathogenic fungi. The IC(50) of compound (E)-1-(2,4-dichlorophenyl)-3-(furan-2-yl)- -prop-2-en-1-one (III(2) ) was 1.20 mg/L against Rhizoctonia solani, suggesting its strong potential as a novel antifungal drug.

[Forest recovery state in wind disaster area of Changbai Mountains, Northeast China].

Based on the field investigation in windfall areas of Changbai Mountains, this paper studied the community recovery characteristics of broad-leaved Korean pine forest (BKPF), spruce fir forest (SFF), and Erman's birch forest (EBF) that were disturbed by wind disaster 23 years ago. The recovery rate of these three forest types was in the order of BKPF > SFF > EBF, and their total community index was 0.49, 0.44, and 0.33, respectively. The effects of the wind disaster on the forest tree species composition and diversity were different. In BKPF, the total number of trees increased significantly, but the tree species number and alpha diversity index had no significant change; in SFF, only the Shannon diversity index and Simpson dominance index decreased significantly; while in EBF, all diversity indices except Pielou evenness index had significant decrease. The responses of dominance tree composition and regeneration to the wind disaster depended on forest types. Comparing with the plots not suffered from wind disaster, the BKPF under wind disaster disturbance had greatly different dominance tree compositions, but the difference in both SFF and EBF was not significant. The BKPF's sapling regeneration was fairly good, while the SFF's was small, and EBF almost had no sapling regeneration. All the results suggested that the effects of wind disaster disturbance on the test forest ecosystems in study areas was not removed even after 23 years, and the recovery of forest after wind disaster disturbance needs a relatively long time.

[Effects of precipitation and interspecific competition on Quercus mongolica and pinus koraiensis seedlings growth].

Aiming at the variation of precipitation pattern caused by global warming, a field simulation experiment was conducted to study the effects of 30% increase (+W) and decrease (-W) of precipitation on the morphology, growth, and biomass partitioning of mono- and mixed cultured seedlings of Quercus mongolica and Pinus koraiensis, the two dominant tree species in temperate broad-leaved Korean pine mixed forest in Changbai Mountains. Comparing with monoculture, mixed culture increased the canopy width and main root length of Q. mongolica seedlings, but decreased the basal diameter, plant height, leaf number, and dry masses of root, stem, leaf and whole plant of P. koraiensis seedlings significantly. Treatment (-W) increased the stem/mass ratio while decreased the main root length of Q. mongolica seedlings, and decreased the main root length, leaf number, dry masses of leaf and whole plant, and leaf/mass ratio, while increased the stem/mass ratio of P. koraiensis seedlings significantly, compared with treatment CK. Treatment (+W) had no significant effect on these indices of the two species. At early growth stage, interspecific competition and precipitation pattern had significant effects on the morphology and growth of the seedlings, and the responses were much stronger for P. koraiensis than for Q. mongolica.

[Application of rDNA-ITS sequence in entomology].

As an important complement of the information obtained from mtDNA, the internal transcribed spacer (ITS) of nuclear ribosomal DNA is being increasingly applied in entomological study. This paper introduced the structure and characters of ITS, and summarized its applications in identifying insect species and in studying their relative relationships and phylogenesis, evolution and spread, and relations with environment. ITS was mainly applied in identifying the species whose morphological differences were subtle. The research of relative relationships and phylogenesis was aimed to understand the species origin and evolution, while the study on the relations with environment was mainly focused on sociological and parasitic insects. The problems and their possible causes in ITS application were discussed.