Root caps provide a protective layer in front of the meristem that protects the meristem from abrasion by soil particles. The continuous production and sloughing of the root cap cells may be an adaptation to decrease the friction at the soil-root interface by acting as a low-friction lining to the channel formed by the root. Experiments were performed which provide the first direct evidence tha...

We explore the effect of microbial activity stimulated by root exudates on the penetrometer resistance of soil and its elastic modulus. This is important because it is a measure of the mechanical strength of soil and it correlates closely with the rate of elongation of roots. A sandy soil was incubated with a synthetic root exudate at different temperatures, for different lengths of time and wi...

As a transportation hub connecting sea and land, the seismic safety of an undersea tunnel is very important. Based on structural stress characteristics shield tunnel, response analysis coastal nuclear power plant under complex foundation carried out in this paper. Firstly, adopting lateral longitudinal displacement methods, authors study variation distribution features rate diameter change join...

The design of a new laboratory facility for evaluating the structural response of small-diameter buried pipes (e.g., leachate collection pipes in landfills) is presented. The pipe is tested within a 2.0 m wide, 2.0 m long, and 1.6 m high prism of soil, subject to large vertical pressures (1000 kPa), with only minimal roughness and deflection of the lateral boundaries. Results from finite elemen...

This study challenges the paradigm that salt marsh plants prevent lateral wave-induced erosion along wetland edges by binding soil with live roots and clarifies the role of vegetation in protecting the coast. In both laboratory flume studies and controlled field experiments, we show that common salt marsh plants do not significantly mitigate the total amount of erosion along a wetland edge. We ...

Subterranean clover (Trifolium subterraneum) is a critical pasture legume in Mediterranean regions of southern Australia and elsewhere, including Mediterranean-type climatic regions in Africa, Asia, Australia, Europe, North America, and South America. Pythium damping-off and root disease caused by Pythium irregulare is a significant threat to subterranean clover in Australia and a study was con...

The electrical conductivity (EC) of soil is generally measured after soil extraction, so this method cannot represent the in situ EC of soil (e.g., EC of soils with different moisture contents) and therefore lacks comparability in some cases. Using a resistance measurement apparatus converted from a configuration of soil microbial fuel cell, the in situ soil EC was evaluated according to the Oh...

Soil compaction is a common problem that affects several soil properties and plant growth. In order to assess the effects of soil strength expressed by its mechanical resistance on roots, a growth chamber experiment was conducted at the Universidade Federal do Rio Grande do Sul, Porto Alegre, in 1994, during 35 days (530 GDD, 0oC base temperature) on a typical Paleudult soil. Treatments, using ...

ture, only a few second-stage juveniles of M. incognita develop and reproduce. Inoculated tomato genotypes that had only a few egg masses on the average when exposed to continuous high soil temperature showed greater resistance under thermoperiodic conditions than tomato entries showing greater numbers of egg masses when exposed to continuous high soil temperature. T h e results suggest that me...