Sapindus delavayi (Franch.) Radlk. (S. delavayi) is an important biological washing material and biomass energy tree species with a peel rich in saponins and a kernel high in oil content. We used the maximum entropy model (MaxEnt) to predict the suitable habitats for S. delavayi in China, screen the dominant environmental factors affecting its distribution, and analyze the changes in its suitable habitats under future climate change. The results provide a scientific basis for its introduction, cultivation, and germplasm resource collection and protection. Twenty-two environmental variables and China distribution data for S. delavayi were used to construct the species distribution model, and the receiver operating characteristic (ROC) curve was used to verify the model’s accuracy. The dominant environmental factors were screened through the jackknife method, then a geographical information system (ArcGIS) was used to determine the level of suitable habitat division and area calculation. The results showed that the MaxEnt model had an excellent predictive effect for which the area under the ROC curve (AUC) value was as high as 0.959. The annual precipitation (Bio18), minimum temperature of the coldest month (Bio6), temperature seasonality (Bio4), and precipitation of the coldest quarter (Bio19) were the dominant environmental factors that affected the distribution of S. delavayi. Under the current climate, the suitable area for S. delavayi is 1,321,308.07 km², and under the four climate scenarios for the 2050s and 2090s, the suitable area is predicted to change by −3.97%~2.57%. Overall, the centroids of the highly suitable habitats will shift by different degrees to the southwest in the future.

Castanopsis sclerophylla was surveyed for its root turion capacity on Laoshan Island in Zhejiang Province and dispersion patterns of seedlings, genetic diversity and genetic variation coefficient was studied using a SSR (simple sequence repeat) molecular marker technique to explore the genetic diversity of C. sclerophylla (Lindl.) Schott as a community and evaluate the community’s development. The results showed that C. sclerophylla had strong root turion capacity, of which type Re2 was the most frequent, accounting for 32.4 and 82.4 % of the seedlings under the stock plant were from within-community mating; the 6 pairs of SSR primers chosen yielded high resolution with 97.6 % polymorphic sites; the within-community genetic diversity was over 88.9 % with stock plants (0.49) > seedling plants (0.45). Apparently, C. scerophyllan on Laoshan Island, propagating mainly by root turions, has developed high genetic diversity within a short period, keeping the community in a stage of stable growth and moving toward a climax community. The tillers, however, aggravate closing of the community so that it receives less pollen from outside. Within-community mating is thus reaching seriously high levels, which can lead to lower within-community genetic variation, a decline in DNA genetic diversity, and is bad for its development. Therefore, human interference should be taken to expand genetic exchange among communities.

In this study, near infrared spectroscopy has been demonstrated to quickly determine the saponin content in soapnut fruits. Partial least squares analysis combined with pre-processing methods and significance multivariate correlation variable selection was introduced to develop a statistical model calibrated for saponin content in soapnut fruits. The results showed that the first derivative yielded the best partial least squares calibration models with spectra of both the surface of dried fruits and the powder of dry seeded fruits with root mean square error of calibration values of 0.85% and 0.59%, respectively. The surface model presented less accuracy than the powder model. However, when the significance multivariate correlation variable selection method was applied to select the best variables from the spectra, the partial least squares models using spectra of surface and powder samples became similar, with higher R² values (0.84 and 0.90), lower root mean square error of calibration values of 0.23% and 0.39%. It was suggested that near infrared spectroscopy could be a promising and rapid method for predicting the saponin content in the soapnut fruits without grinding them into powder.

The complete chloroplast genome sequence of Chaenomeles cathayensis and Chaenomeles thibetica was characterized from Illumina pair-end sequencing. The length of C. cathayensis and C. thibetica chloroplast genome of was 159,875 bp and 159,907 bp, respectively. The C. cathayensis chloroplast genome contained a large single-copy region (LSC) of 87,813bp, a small single-copy region (SSC) of 19,304 bp, and two inverted repeat (IR) regions of 26,379 bp, which is a quadripartite structure. Similarity, The C. thibetica chloroplast genome also contained a quadripartite structure, including a LSC region (87,851 bp), a SSC region (19,298 bp), and two IR regions (26,379 bp). The overall GC content of C. cathayensis and C. thibetica are both 36.57%. The C. cathayensis and C. thibetica chloroplast genome contains 130 complete genes, including 85 protein-coding genes, 37 tRNA genes, and 8 rRNA genes. The C. thibetica chloroplast genome contains 130 complete genes, including 85 protein-coding genes, 37 tRNA genes, and 8 rRNA genes. The neighbour-joining phylogenetic analysis showed that C. cathayensis and C. thibetica clustered together, indicated that C. cathayensis and C. thibetica have closed evolutionary relationship compared with other Chaenomeles species.