scholarly journals Azimuthal variation in nighttime sap flow and its mainly influence factors of Populus tomentosa

2020 ◽  
Vol 44 (8) ◽  
pp. 864-874
Author(s):  
Fei-Fei ZHAO ◽  
Xu MA ◽  
Nan DI ◽  
Ye WANG ◽  
Yang LIU ◽  
...  
Keyword(s):  
Sap Flow ◽  
Influence Factors ◽  
Populus Tomentosa ◽  
Azimuthal Variation

scholarly journals An undiscovered facet of hydraulic redistribution driven by evaporation—A study from a Populus tomentosa plantation

2021 ◽  
Author(s):  
Yang Liu ◽  
Nadezhda Nadezhdina ◽  
Nan Di ◽  
Xu Ma ◽  
Jinqiang Liu ◽  
...  
Keyword(s):  
Water Transport ◽  
Water Flow ◽  
Sap Flow ◽  
Water Movement ◽  
Transport Model ◽  
Lateral Roots ◽  
Populus Tomentosa ◽  
Hydraulic Redistribution ◽  
Evaporative Demand ◽  
Dry Conditions

Abstract Maintenaining the activity and function of the shallow root system of plants is essential for withstanding drought stress, but the associated mechanism is poorly understood. By investigating sap flow in 14 lateral roots (LRs) randomly selected from trees of a Chinese white poplar (Populus tomentosa) plantation receiving three levels of irrigation, an unknown root-water transport mode of simultaneous daytime bi-directional water flow was discovered. This mode existed in five LRs confined to the surface soil without attached sinker roots. In the longer term, the bi-directional water flow was correlated with the soil water content. However, within the day, it was associated with transpiration. Our data demonstrated that bi-directional root sap flow occurred during the day, and was driven by evaporative demand, further suggesting the existence of circumferential water movement in the LR xylem. We named this phenomenon evaporation-driven hydraulic redistribution (EDHR). A soil-root water transport model was proposed to encapsulate this water movement mode. EDHR may be a crucial drought-tolerance mechanism that allows plants to maintain shallow root survival and activity by promoting root water recharge under extremely dry conditions.

An importance of soil humidification in forming of avifauna of arboreal plantation in the Biosphere reserve «Askania Nova» (un-reproductive period)

2016 ◽  
Vol 27 (3-4) ◽  
pp. 55-69
Author(s):  
M. A. Listopadsky
Keyword(s):  
Soil Moisture ◽  
Influence Factors ◽  
Data Communication ◽  
Biosphere Reserve ◽  
Reproductive Period ◽  
Defined Contribution ◽  
Separate Species ◽  
Steppe Birds ◽  
Reserve Forest ◽  
Autumn And Winter

With gradient analysis investigated the role of soil moisture in the formation of the modern population of birds in the reserve forest plantations. Soil moisture was divided into seven grades. For this purpose used grass cover and the coefficient of local moistening. His proposed PhD L. P. Travleev. This method allows knowing the degree of influence of soil moisture at the birds. We analyzed birds species composition, population, placement in space and power of influence factors (soil moisture). Investigations were carried out on the territory of the Biosphere Reserve «Askania Nova». We studied the birds which live in the reserve at the end of the summer, autumn and winter. This happened from 2006 to 2013 years. Specially was studied as permanently specific form of birds is found in a particular humidity. The degree of coupling was studied using the amount of information that transmits to the local bird humidification. For 68 species of birds are the options of the population density, coefficient koligatsii and data communication with the seven variants of soil moisture. For all kinds of set information «price» of each option dampening that contributes to the formation of a particular community of birds. Thus, the defined contribution to the formation of soil moisture forest bird communities. Species representation and density gradient within the test moisture is not in direct linear relationship from moisture and ranges from 11 (very coldly) to 50 species (moist soil). The density of the community varies from 0,5 birds / hectare (very dry) to 269 birds / hectare (fresh soil). The strongest link between the information and the formation of moisture gradient structure avifauna is typical in a fresh soil – bird on the edge, and wet – forest representatives. These types of humidification function is performed starting in the formation of two major blocks dendrophilous community. The steppe birds give way to forest representatives when the soil slightly moist. The main conclusion of our study includes the following: than wetter the soil the more species of birds lives in the forest; some graduation humidity are the most important for separate species of birds; it is very important for birds, there are places where one can drink water. Further invasive alien species can occur where the soil is moist. Forest with dry soil is already fully occupied by birds.

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