Browsing by Subject "Rhizosphere"

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  • Huang, Yue; Zou, Jie; Kang, Zongjing; Zhang, Xiaoping; Penttinen, Petri; Zhang, Xiaoping; Li, Xiaolin (2021)
    We inoculated Tuber aestivum and Tuber sinoaestivum on Carya illinoinensis to explore the effects of inoculation on host plant growth, enzyme activities, the physicochemical properties of rhizosphere soil, the denitrifying bacterial community in the rhizosphere, and the distribution of mating type genes in the rhizosphere. We found that the Tuber spp. inoculation increased the height of the host plant and that the stem circumference of the host was greater two months after inoculation. Six months after inoculation, the peroxidase activity of the seedlings inoculated with T. sinoaestivum was higher than that of the control. At four and six months after inoculation, the superoxidase dismutase activities of the seedlings inoculated with T. aestivum were higher than those of the seedlings inoculated with T. sinoaestivum. Six months after inoculation, nitrate nitrogen content was lowest in the control and highest in the T. sinoaestivum treatment. Among the nirS-type denitrifying bacteria community, the relative abundances of Proteobacteria were high. T. aestivum and T. sinoaestivum inoculation did not affect the diversity of denitrifying bacteria. The mating type genes MAT1-1-1 and MAT1-2-1 were detected in the rhizosphere of C. illinoinensis inoculated with T. sinoaestivum and T. aestivum, and MAT1-1-1 dominated over MAT1-21. (c) 2021 British Mycological Society. Published by Elsevier Ltd. All rights reserved.
  • Liu, Miao; Wang, Yuting; Liu, Xiucheng; Korpelainen, Helena; Li, Chunyang (2021)
    In this study, we intended to investigate the responses of rhizospheric bacterial communities of Populus cathayana to excess Zn under different planting patterns. The results suggested that intersexual and intrasexual interactions strongly affect plant growth and Zn extraction in both sexes, as well as rhizosphere-associated bacterial com-munity structures. Females had a higher capacity of Zn accumulation and translocation than males under all planting patterns. Males had lower Zn accumulation and translocation under intersexual than under intrasexual interaction; the contrary was true for females. Females harbored abundant Streptomyces and Nocardioides in their rhizosphere, similarly to males under intersexual interaction, but differed from single-sex males under excess Zn. Conversely, intersexual interaction increased the abundance of key taxa Actinomycetales and Betaproteobacteria in both sexes exposed to excess Zn. Males improved the female rhizospheric microenvironment by increasing the abundance of some key tolerance taxa of Chloroflexi, Proteobacteria and Actinobacteria in both sexes under excess Zn in intersexual interaction. These results indicated that the sex of neighboring plants affected sexual differences in the choice of specific bacterial colonizations for phytoextraction and tolerance to Zn-contaminated soils, which might regulate the spatial segregation and phytoremediation potential of P. cathayana females and males under heavy metal contaminated soils.
  • Montaldo, Nicola; Oren, Ram (2022)
    Trees typically survive prolonged droughts by absorbing water from deeper layers. Where soils are shallow, roots may be extract water from the underlying fractured bedrocks. In dry seasons, surface-soil moisture dynamics reflect hydraulic redistribution (HR). HR is usually estimated based on the gradient of mean, or bulk, soil water potential among layers in the rooting zone (HRB). This approach neglects the potential effect of spatial heterogeneity of water content at the millimeter scale between the rhizosphere and bulk soil. We proposed to account for the rhizosphere water balance, estimating HR to the rhizosphere (HRR) of the dry surface soil from the underlying fractured rock. The model was evaluated using a 15-year dataset collected in Sardinia. When the typical approach, based on moisture gradients among bulk soil layers, was used for estimating HRB, tree transpiration was underpredicted in all seasons, especially in spring and summer. Forcing the model with measured tree transpiration, HRB decreased during spring and summer, while the contribution of the underlying rock layer to tree transpiration was threefold that estimated using HRR-based model. The average water content of the bulk surface soil layer was very low, reaching 0.06 in the driest summers while showing little diurnal dynamics; however, concentrating water in roughly estimated rhizosphere volume, produced rhizosphere water content appreciably higher (approximate to 0.16), and much more dynamic. Predicted HRR dominated evapotranspiration (60% - 65%) in dry springs and summers reaching 80% of tree transpiration. Most importantly, the proposed rhizosphere-HR model correctly predicts the diurnal dynamics of tree transpiration year-round, and the grass transpiration in its active spring period. Eco-hydrological models operating at sub-daily scale should consider partitioning the soil to rhizosphere volume, thus allowing both diagnostic and prognostic estimates of diurnal biosphere-atmosphere mass and energy exchanges.