A variable pupil generally regulates the amount of incoming light available for image formation on the retina. However, some of the semi-aquatic snakes (North American Gartersnakes, Thamnophis) that forage in relatively low light conditions reduce the pupil aperture in response to submergence underwater at the expense incoming light. Given that these snakes have all-cone retinas, reduction of i...

Two pot and two field experiments were conducted at Patuakhali Science and Technology University research farm to investigate the contribution of tidal submergence to phosphorus nutrition and yield of rice. Pot and field experiments were conducted in the Aus and Aman seasons of 2009, respectively. The factorial experiments include two levels of water sourcei) tidal water and ii) ground water, a...

1. Bradycardia in response to forced submergence was habituated in dabbling (Anas platyrhynchos, Linnaeus) and diving (Aythya americana, Eyton) ducks by repetitively submerging the animals, each day for several days, for periods of 40 and 20 s, respectively. The onset of pronounced bradycardia was delayed with each successive trial, until little or no bradycardia occurred during submergence. Di...

We have shown previously that ethylene, which accumulates in the air spaces of submerged stem sections of rice (Oryza sativa L. cv "Habiganj Aman II"), is involved in regulating the growth response caused by submergence. The role of gibberellins in the submergence response was studied using tetcyclacis (TCY), a new plant growth retardant, which inhibits gibberellin biosynthesis. Stem sections e...

One hundred and sixty rice varieties from the tidal and flood prone areas of south and south East Asian countries were analyzed. Samples sizes were: 50 varieties from Bangladesh (deepwater, tidal and flood prone rice and modern varieties), 14 varieties from India (flood prone rice), 16 varieties from Sri Lanka (flood prone rice), 7 varieties from Vietnam (tidal varieties), 69 varieties from Ind...

Enzymes that reduce the aldehyde chemical grouping (i.e. H-C=O) to its corresponding alcohol are probably crucial in maintaining plant health during stress. Succinic semialdehyde (SSA) is a mitochondrially-generated intermediate in the metabolism of gamma-aminobutyrate (GABA), which accumulates in response to a variety of biotic and abiotic stresses. SSA can be reduced to gamma-hydroxybutyrate ...

Flooding imposes stress upon terrestrial plants since it severely hampers gas exchange rates between the shoot and the environment. The resulting oxygen deficiency is considered to be the major problem for submerged plants. Oxygen microelectrode studies have, however, shown that aquatic plants maintain relatively high internal oxygen pressures under water, and even may release oxygen via the ro...

Histone modifications such as methylation and acetylation in the chromatin surrounding a gene are thought to regulate transcriptional activity. In this study, to determine whether dynamic changes occur in histone modification on the loci of stress-responsive genes in plants, we chose rice submergence-inducible ADH1 and PDC1 genes. When submerged, the rice ADH1 and PDC1 genes were activated in a...

Submergence and drought are major constraints to rice (Oryza sativa) production in rain-fed farmlands, both of which can occur sequentially during a single crop cycle. SUB1A, an ERF transcription factor found in limited rice accessions, dampens ethylene production and gibberellic acid responsiveness during submergence, economizing carbohydrate reserves and significantly prolonging endurance. He...