El Amrani Belkacem, Amraoui Mohammed Bendriss
Laboratory of Biotechnology, Environment, Food and Health (LBEFH), Department of Biology, Faculty of Sciences Dhar el Mahraz, Sidi Mohammed Ben Abdellah University, P.O. Box 1796, Atlas, Fez, Morocco.
Scientifica (Cairo). 2020 Aug 18;2020:7538698. doi: 10.1155/2020/7538698. eCollection 2020.
The biomechanical root flexibility in response to hydromechanical soil heterogeneity is the most determining factor of the root architecture which plays a paramount role in mycorrhizal infection and allows the seedlings to adapt to the environmental constraint. We examined the impact of five different hydromechanical medium properties (hydroponics, vermiculite, vermiculite-gravel, sawdust, and sand) on the morphology, physiology, and anatomy of seedlings at a controlled growth chamber. The growth of the seedling is strongly stimulated by the hydroponic medium through the stimulation of the aerial part dry weight and the main root length. However, the sand medium increases the main root dry weight by the radial expanse stimulation at the level of the epidermis, vascular cylinder, and cortex and compensates the less root architecture by the stimulation of the xylem and phloem areas. In contrast to sand and hydroponic media, the sawdust medium stimulates the phloem/xylem ratio, the root architecture, and the short roots. The Pearson bilateral correlation shows that the aerial part dry weight is positively correlated with the permeability, porosity, and water-holding capacity and negatively with the bulk density and density at saturation, whereas the short root production is negatively correlated with the permeability and water-holding capacity. Hence, the hydromechanical characteristics of the soils must be taken into account in the reforestation and mycorrhization attempts.
根系对水力机械土壤异质性的生物力学柔韧性是根系结构的最决定性因素，根系结构在菌根感染中起至关重要的作用，并使幼苗能够适应环境限制。我们在可控生长室内研究了五种不同的水力机械介质特性（水培、蛭石、蛭石-砾石、锯末和沙子）对幼苗形态、生理和解剖结构的影响。水培介质通过刺激地上部分干重和主根长度，强烈促进了幼苗的生长。然而，沙子介质通过刺激表皮、维管束和皮层水平的径向扩展来增加主根干重，并通过刺激木质部和韧皮部区域来弥补根系结构较少的问题。与沙子和水培介质不同，锯末介质刺激韧皮部/木质部比率、根系结构和短根。皮尔逊双边相关性表明，地上部分干重与渗透率、孔隙率和持水量呈正相关，与容重和饱和密度呈负相关，而短根产量与渗透率和持水量呈负相关。因此，在造林和菌根化尝试中必须考虑土壤的水力机械特性。
