We screened 80 Asian rice (Oryza sativa L.) cultivars for the presence of submergence-tolerance gene SUB1A-1 and floating genes SNORKEL1 (SK1) SNORKEL2 (SK2), found that deepwater cultivar Baisbish (BSB) submergence-tolerant Flood Resistant 13A (FR13A) both possess SK1/2. When BSB FR13A seedlings were completely submerged, spindly growth shoots was induced in but not FR13A. Submergence signific...

Submergence strongly stimulates petiole elongation in Rumex palustris, and ethylene accumulation initiates and maintains this response in submerged tissues. cDNAs from R. palustris corresponding to a 1-aminocyclopropane-1-carboxylate (ACC) oxidase gene (RP-ACO1) were isolated from elongating petioles and used to study the expression of the corresponding gene. An increase in RP-ACO1 messenger wa...

A combination of flooding and salinity is detrimental to most plants. We studied tolerance of complete submergence in saline water for Melilotus siculus, an annual legume with superhydrophobic leaf surfaces that retain gas films when under water. M. siculus survived complete submergence of 1 week at low salinity (up to 50 mol m(-3) NaCl), but did not recover following de-submergence from 100 mo...

Plants require water for growth and development, but excessive water negatively affects their productivity and viability. Flash floods occasionally result in complete submergence of plants in agricultural and natural ecosystems. When immersed in water, plants encounter multiple stresses including low oxygen, low light, nutrient deficiency, and high risk of infection. As floodwaters subside, sub...

This research aims to study jet downstream scour model under the influence of changes of water level. It also studies and analyzes different parameters and components of diffusion of submerged jet flow in an acceptor fluid and scour hole dimensions. To achieve the objectives, a physical model was made in proportion to the research title. With the Froude number increasing in a nozzle discharge, ...

The quantification of flow resistance in complex natural channels continues to be a key source of uncertainty in basic research, engineering, and environmental management. This paper describes a meta-analysis of data compiled from a wide range of sources and flow conditions in mountain streams that compares the accuracy of equations developed by Jarrett (1984), Hey (1979), Bathurst (1985) and B...

Reservoirs often have highly fluctuating water levels. The perimeters of these impoundments, which alternate between being exposed or inundated by water (drawdown zone), are used by nesting birds, but at the risk of nest submergence when water levels rise. For species that nest above the ground in shrubs, foraging and predation may also be affected by flooded habitat. Our objective was to clari...

The activities of antioxidant enzymes and levels of antioxidants involved in oxygen detoxification were studied in seedlings of three indica rice (Oryza sativa L.) cultivars, namely Panikekoa and T 1471 that show good capacity for anaerobic seedling establishment (tolerant reaction) and IR 42 which has a poor anaerobic seedling establishment capacity (susceptible reaction). The activities of th...

Terrestrial plants experience multiple stresses when they are submerged, caused both by oxygen deficiency due to reduced gas diffusion in water, and by shade due to high turbidity of the floodwater. It has been suggested that responses to submergence are de facto responses to low light intensity. We investigated the extent to which submergence and shade induce similar acclimation responses by c...