Author Correction: Labile organic carbon pools and enzyme activities of Pinus massoniana plantation soil as affected by understory vegetation removal and thinning.[Pubmed: 30042478]

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[Growth responses of Castanopsis hystrix and Pinus massoniana plantations to throughfall reduction in subtropical China.][Pubmed: 30039672]

为了预测和评估全球气候变化背景下森林生长和生产力对降水格局变化和季节性干旱的响应,以南亚热带红锥和马尾松人工林为对象,设置穿透雨减少50%和不减雨(对照)处理,开展连续3年(2015—2017年)的模拟试验,研究降雨减少对人工林胸径生长、凋落物量和叶面积指数的影响.结果表明: 与对照相比,穿透雨减少导致红锥2017年胸径增长量显著降低31.8%,而对马尾松无影响;红锥叶面积指数平均降低8.8%,马尾松叶面积指数降低7.2%或者不变;红锥林2015年枝凋落量和2017年凋落物总量分别增加29.6%和35.8%,马尾松林2015年其他树种(除了马尾松以外)叶凋落量显著减少50.7%,而其他凋落物组分无显著变化.短期穿透雨减少对人工林产生了干旱胁迫作用,这种作用存在年际变异和树种差异.

[Changes of total phenols and condensed tannins during the decomposition of mixed leaf litter of Pinus massoniana and broad-leaved trees.][Pubmed: 30039660]

采用凋落物分解袋法,研究四川低山丘陵区马尾松与檫木、香椿、香樟3种阔叶树种的混合凋落叶及纯马尾松凋落叶分解过程中总酚和缩合单宁的变化特征.设置马尾松:檫木质量比为6:4、7:3、8:2,马尾松:香椿质量比为6:4、7:3、8:2,马尾松:香樟质量比为6:4、7:3、8:2混合处理.结果表明:经过180 d的分解,纯马尾松凋落叶缩合单宁的降解率为84.4%,混合凋落叶缩合单宁的降解率均高于纯马尾松凋落叶.在所有组合中,马尾松:香樟6:4混合凋落叶的缩合单宁和总酚降解率最高,分别为90.3%和68.6%,凋落叶的混合促进了马尾松凋落叶缩合单宁和总酚的分解.随着分解时间的延长,马尾松与3种阔叶凋落叶所有混合处理缩合单宁的降解率均呈现先上升后趋于稳定的趋势.而纯马尾松凋落叶、马尾松:香樟(7:3)和马尾松与香椿的所有混合处理总酚的降解率呈现在分解前90 d上升此后下降的趋势;马尾松与檫木的所有混合处理及马尾松:香樟6:4和8:2混合处理总酚降解率呈现上升趋势.混合凋落叶分解过程中,单宁和总酚的变化特征还与凋落物基质质量、凋落物分解相关酶(多酚氧化酶、过氧化物酶、亮氨酸氨基肽)的活性有关.

[Responses of soil and aggregate-associated organic carbon mineralization to throughfall reduction in a Pinus massoniana plantation.][Pubmed: 29974685]

None

Soil propagule bank of ectomycorrhizal fungi associated with Masson pine (Pinus massoniana) grown in a manganese mine wasteland.[Pubmed: 29870548]

Ectomycorrhizal (ECM) fungal propagule bank could facilitate the regeneration and plantation of seedlings in disturbed area. In this study, Masson pine (Pinus massoniana) seedlings were used to bait the ECM fungal propagule bank buried in the soils collected from a manganese (Mn) mine wasteland and a non-polluted area in China. After 6-month growth, we found the seedlings grown in the Mn mine soil (Mn:3200 mg kg-1) did not display any toxicity symptoms. Based on morphotyping and ITS-PCR sequencing, we identified a total of 16 ECM fungal OTUs (operative taxonomic units) at 97% similarity threshold, among which 11 OTUs were recovered in the Mn mine soils and 14 in the non-polluted soil. Two soil types shared 9 OTUs and both of them were dominated by a Tylospora sp. Based on those soil propagule banks in Masson pine forests reported in previous, we speculated that some Atheliaceae species may be preferred in the soil propagule bank of some pine species, such as Masson pine. In addition, NMDS ordination displayed geographical position effects on soil propagule banks in five Masson pine forest from three sites at regional scale. In conclusion, Masson pine ECM seedlings could grow well in the Mn wasteland as a suitable tree species used for reforestation application in Mn mineland, in addition, Mn pollution did not alter the dominant ECM fungal species in the soil propagule banks.

Effects of mixed leaf litter from predominant afforestation tree species on decomposition rates in the Three Gorges Reservoir, China.[Pubmed: 29803039]

To determine whether mixed plantations can improve nutrient cycling and to elucidate the mechanisms of such effects, a field litterbag experiment with seven treatments involving Pinus massoniana (P.), Cupressus funebris (C.) and Quercus variabilis (Q.) litter in equal mass proportions (pure litter; pairwise combinations; and the combination of all three species) was conducted in a Pinus massoniana plantation in the region of the Three Gorges Reservoir, China. We measured mass loss and the release of C, N and P from the litter treatments and assessed the effects of mixing litter in each sampling phase and for various decomposition periods. At the end of the study, the mass loss and release of C, N and P among the treatments relative to their initial contents ranged from 47.6% to 62.8%, 59.5% to 75.2%, 63.5% to 78.2% and 58.9% to 72.6%, respectively. Primary mass loss and nutrient release occurred during a phase with high temperatures and precipitation, and decomposition was closely correlated with the initial lignin/N ratio and N concentration. Compared with the decay values of Quercus litter, mixing litter increased N release by 1.2% for the P. + Q. and C. + Q. combinations and increased P release by 3.0-6.3% for the three litter mixture combinations. Additionally, the P. + Q. and C. + Q. two-species mixtures exhibited greater decay than the three-species mixture. Mixing the two coniferous species (P. + C.) also increased decomposition. Furthermore, positive nonadditive mass loss occurred after incubation for 240 d, and mixing effects on the nonadditive release of C, N and P occurred immediately in 60 d incubations in all treatments. In conclusion, mixing these three species or two of species can improve material cycling in plantations, and Quercus appears to be a priority candidate for mixed planting with Pinus and/or Cupressus.

Taishan Pinus massoniana Pollen Polysaccharides Enhance Immune Responses in Chickens Infected by Avian Leukosis Virus Subgroup B.[Pubmed: 29768058]

Immunosuppressive virus, which can cause suppressed immunity and vaccination failure, frequently occurs in chicken flocks and seriously destroys the poultry industry. Our previous studies have reported that Taishan Pinus massoniana pollen polysaccharide (TPPPS) possess immunomodulatory effects and improve the immune effects of vaccines. In this study, avian leukosis virus subgroup B (ALV-B) was chosen as immunosuppressive virus to artificially establish immunosuppressive models in chickens, and the immune modulatory ability of TPPPS on the immune response of chickens was evaluated. Four randomly assigned groups (Group I-IV) of these immunosuppressed chickens were administered with TPPPS at doses of 0, 100, 200, and 400 mg/kg (every kilogram chick), respectively. Group V was administered with saline as control. At seven day old, 10 chickens randomly selected from Group I-V were inoculated with the attenuated Newcastle disease (ND) vaccine. The results showed that during the monitoring period, TPPPS significantly enhanced weight of immune organs, peripheral lymphocyte proliferation, the percentage of CD4+ and the ratio of CD4+/CD8+, IL-2 and IFN-γ production, and ALV-B antibody positive rate of chickens in a dose-dependent manner, with 400 mg/kg TPPPS being the most effective. In addition, the antibody titer against Newcastle disease virus (NDV) in Group IV with 400 mg/kg was significantly higher than those in other groups. We observed the stronger immunity in the TPPPS group, which indicates that TPPPS could be used as an immunoenhancer to relieve immunosuppression caused by ALV-B in the poultry industry.

Intra-annual wood formation of subtropical Chinese red pine shows better growth in dry season than wet season.[Pubmed: 29757427]

China's subtropical forests play a vital role in sequestering global carbon; therefore, it is critical to conduct a precise investigation of intra-annual wood formation in these ecosystems to clarify the mechanisms behind this. Two field experiments were established in Chinese subtropical forests to monitor weekly the intra-annual xylem formation of Pinus massoniana Lamb. from January to December 2015, using the recently developed micro-sampling approach. The effects of climate on wood formation were also assessed using linear or mixed models. Results indicate that there is an inactive period that might be semi-dormancy in subtropical pine ecosystems in January compared with the complete dormancy in temperate and boreal ecosystems and the fully active or short-term dormancy in tropical ecosystems. The duration of xylem formation of Chinese red pine in subtropical China in 2015 was 4-6 months longer than temperate and boreal forests. Moreover, trees were found to grow better during the dry season than the wet season, indicating that the Chinese red pine ecosystem is more strongly regulated by net energy than by environmental factors. Our findings indicate that China's subtropical pine forests may benefit from the expected longer dry seasons, possibly leading to better forest growth and improved carbon sequestration under continued climate warming.