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Excessive nutrient inputs imperil the stability of forest ecosystems via modifying the interactions among soil properties, microbes, and plants, particularly in forests composed of cash crops that are under intensive disturbances of agricultural activities, such as Torreya grandis. Understanding the potential drivers of soil microbial community helps scientists develop effective strategies for balancing the protection and productivity of the ancient Torreya forest. Here, we assayed the link between plant and soil parameters and prokaryote communities in bulk soil and T. grandis rhizosphere in 900-year-old stands by detecting plant and soil properties in two independent sites in southeastern China. Our results showed no apparent influence of stand age on the compositions of prokaryote communities in bulk soil and T. grandis rhizosphere. In contrast, soil abiotic factors (i.e., soil pH) overwhelm plant characteristics (i.e., height, plant tissue carbon, nitrogen, and phosphorus content) and contribute most to the shift in prokaryote communities in bulk soil and T. grandis rhizosphere. Soil pH leads to an increase in microbiota alpha diversity in both compartments. With the help of a random forest, we found a critical transition point of pH (pH = 4.9) for the dominance of acidic and near-neutral bacterial groups. Co-occurrence network analysis further revealed a substantially simplified network in plots with a pH of4.9 versus samples with a pH of ≥4.9, indicating that soil acidification induces biodiversity loss and disrupts potential interactions among soil microbes. Our findings provide empirical evidence that soil abiotic properties nearly completely offset the roles of host plants in the assembly and potential interactions of rhizosphere microorganisms. Hence, reduction in inorganic fertilization and proper liming protocols should be seriously considered by local farmers to protect ancient Torreya forests.

The Masson pine breeding programme has advanced to the third cycle. However, breeding and deployment are based largely on plantation inventory zones rather than biological patterns of genotype by environment interaction (G × E) and consequently cannot deliver optimal genetic gains across the whole plantation estate. The present study analysed G × E in family tests of Masson pine planted in the eastern and central regions of China. Twenty-six controlled pollination families were selected at three experimental sites. Measurements were performed at 8 years of age for diameter at breast height, total height, and volume. The genotype and G × E (GGE) biplot was used to study the effects of G × E, and the type B correlation coefficients was used to evaluate the extent of G × E. Significant site, family and family × site effects on growth traits were found (p h f 2 ) and individual heritability ( h s 2 ) ranged from 0.59 to 0.84 and 0.16 to 0.38. The type B correlation refers to genetic correlation between different environments. In this study, type B correlation coefficients between tested sites were all less than 0.8, indicating significant G × E among families at different sites. The volume of family 6 was highest at the TZS and XJ sites, and that of family 4 was highest at the SW site. 12 superior families and 49 superior individual trees were selected, and, as determined by comparison with the controls, the real gain (G) of volume was 23.70% and 279.53%, respectively. At the three sites, the individual volumes of families 6, and 15 were larger and more stable than those of other families, while family 4 was large and unstable. The analyses revealed that those families that perform best in all the tests can be planted in areas with similar environmental traits to the sites tested here. Excellent genotypes with stable and high yield can provide a basis for follow-up breeding work.

A comparative analysis was undertaken of the genetic diversity and genetic structure of three coordinal tree species from southeastern China. The species Phoebe chekiangensis C.B. Shang, Phoebe bournei (Hemsl.) Yang and Machilus pauhoi kanehira are all valued for their timber. Nine populations from two provinces were screened for variability with ISSR markers. Percentage of polymorphic loci, Nei's gene diversity, and Shannon's index were lower in P . chekiangensis ( PPL % = 78.8%, h = 0.2301, and I = 0.3522) than in P . bournei ( PPL % = 90.3%, h = 0.3223, and I = 0.4776) or M . pauhoi kanehira ( PPL % = 92.0%, h = 0.3714, and I = 0.5412). Larger populations were found to possess greater genetic diversity. Distinct genetic differentiation was found to have taken place in P. bournei , and barrier analysis showed two barriers in the four populations studied. Special environments were found to influence population differentiation.

Ormosia hosiei is native to China and valued for its timber. In order to help preserve this endangered wild species, we investigated the distribution of O. hosiei populations in southern China. Based on ISSR markers, 101 clear and reproducible DNA fragments were generated. Of these, 96 (95.1%) were polymorphic. Shannon’s index (I) and Nei’s gene diversity (h) were 0.5483 and 0.3747, indicating a high level of genetic diversity. Moreover, there was a lack of significant association between genetic and geographical distances in the populations. The distribution of genetic diversity among the wild populations of O. hosiei in southern China may be the result of events in the species’ evolutionary history, including habitat fragmentation and habitat damage caused by human activity. Based on these findings, we suggest that areas with larger populations of O. hosiei should take effective measures to ensure the conservation.