| 1 | Morphological plasticity and phosphorus uptake mechanisms of hybrid Eucalyptus roots under spatially heterogeneous phosphorus stress显示文摘In this study, we subjected the root systems of eight Eucalyptus hybrids currently cultivated in southern China to heterogeneous phosphorus stress to provide a scientific basis for the selection of a highly phosphorusefficient Eucalyptus variety. When the ability of these hybrids to locate phosphorus under different experimental conditions(phosphorus supply in a homogeneous or heterogeneous manner vs. no phosphorus supply) was compared, the main growth characteristics of Eucalyptus,such as plant height, diameter, dry mass, and phosphorus content, significantly improved when the phosphorus supply was increased from no phosphorus or heterogeneous phosphorus(half of the phosphorus amount) to homogeneous phosphorus. Across these three conditions, the growth traits of different Eucalyptus hybrids differed significantly, indicating different adaptabilities of the hybrids to various phosphorus conditions. The growth traits of the aboveground tissues of Eucalyptus under different phosphorus conditions were largely influenced by the morphology of the underground root system. In addition, the root morphology of Eucalyptus under heterogeneous phosphorus treatment suggested that there were two mechanisms for locating nutrients. Eucalyptus hybrids such as Urophylla 3229, Grandis 9, Guanglin 3, 201-2, and Dunn produced more roots proximal to the phosphorus supply; the other hybrids, Urophylla 3216, Grandis 5, and Guanglin 9, relied mainly on the growth of roots opposite the phosphorus supply to obtain adequate nutrients for growth. With these two strategies, a wide range of nutrients was obtained, root distribution was greater, more soil volume was covered, the contact area of the roots with soil phosphorus was increased, and the uptake of phosphorus by the root system was increased. These results demonstrate that Eucalyptus relies on changes to morphological characteristics of the root system to increase accessibility to phosphorus resources. | Chuifan Zhou Wuya Jiang Ying Li Xiaolong Hou Aiqin Liu Liping Cai | 2017 | Journal of Forestry Research2017，28，4： | 3 |
| 2 | Effects of biochar and litter on carbon and nitrogen mineralization and soil microbial community structure in a China fir plantation显示文摘To investigate the effects of biochar addition(1 or 3%)to the soil of a China fir plantation with or without litter,we conducted a 90-day incubation experiment.We also studied the C and N dynamics and the microbial community structure of the soil.In soil without litter,the application of biochar at a rate of 3%significantly decreased CO2 emissions,while addition of 1%biochar had no effect.Biochar application did not affect the net N mineralization rate but significantly reduced the NH4?concentration after 90 days.In litter-enriched soil,biochar application had no significant effect on total CO2 emissions;however,application of 3%biochar significantly reduced the net N mineralization rate.Biochar application to soil with or without litter immediately reduced the dissolved organic carbon(DOC)concentration independent of the application rate,which was primarily due to sorption of DOC by the biochar.Phospholipid fatty acid analysis demonstrated that both concentrations of added biochar to soil(with or without litter)altered the soil microbial community structure at the end of incubation,although the effect of biochar was not as strong as the effect of time or litter application.The effect of biochar addition alone on microbial community structure was inconsistent over time.Litter added to soil significantly increased fungi and reduced Gram-positive bacteria.In the presence of litter,biochar applied at both 1%and 3%significantly increased(p<0.05)the proportion of actinomycete only at day 90.Our results indicate biochar as a potentially effective measure for C sequestration in the test soil of a China fir plantation,even in the presence of litter. | Ying Li Chuifan Zhou Yunxiao Qiu Mulualem Tigabu Xiangqing Ma | 2019 | Journal of Forestry Research2019，30，5： | 3 |
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