Submergence In Water Research Articles

Habitat Selection of Rana pipiens and Rana sylvatica during Exposure to Warm and Cold Temperatures

-In natural field conditions Rana pipiens is an aquatic hibernator and Rana sylvatica a terrestrial hibernator. Habitat selection in the laboratory at low temperatures was similar to hibernating habitat in the field. Habitat preference tests were conducted in warm (15 C) and near-freezing (1.5 C) air temperatures. Rana pipiens shows no preference for either water or land at 15 C, but prefers water to land at 1.5 C. When given a choice between bare moist soil or moist soil covered by leaf litter, R. pipiens remains on the uncovered surface in both warm and cold conditions. Rana sylvatica prefers land to water at both 15 C and 1.5 C. At 1.5 C R. sylvatica burrows into soil and seeks cover beneath leaf litter; it also selects moist soil rather than wet mud during exposure to cold. Rana sylvatica can survive prolonged submergence in ice-covered water. Physiological adaptations such as cryoprotectants and the geographic distribution of R. sylvatica are discussed in relation to habitat selection at low temperatures.

Plasma ion balance of North American freshwater turtles during prolonged submergence in normoxic water

1. 1. Plasma ion (Na +, K +, Cl −, HCO − 3, lactate, Ca, and Mg) concentrations were measured during apneic submergence in aerated water at 10°C of 4 species of freshwater turtles: Chelydra serpentina serpentina (Chelydridae), Chrysemys picta bellii (Emydidae), Sternotherus odoratus (Kinosternidae), and Trionyx spiniferus asperus (Trionychidae). Measurements were made at intervals up to 21, 13, 100, and 100 days, respectively. In addition, final wet and dry masses were measured in Sternotherus and Trionyx and compared to control values to assess changes in body water and dry mass. 2. 2. In Chelydra and Chrysemys, which have a relatively poor aquatic O 2 uptake capacity, plasma ions changed as previously reported in animals submerged in anoxic water; [Na +] was unchanged, [K +], [Ca], and [Mg] were evaluated, and [Cl −1] and [HCO − 3] were depressed. This overall pattern is probably a regulated response and respresents a compensation for the severe acidosis exhibited by these animals. 3. 3. In Sternotherus and Trionyx, which have effective aquatic respiration and could remain submerged much longer, plasma ion concentrations, except [K +] and [lactate], fell due (largely in Sternolherus, less so in Trionyx to dilution by water uptake. Both species were slightly alkalotic after prolonged normoxic submergence, and we suggest that changes in ion concentrations can be considered as compensatory to this alkalosis. 4. 4. We conclude that these turtles fall into two distinct physiologic response types. In Chelydra and Chrysemys, normoxic submergence at 10°C is limited principally by acidosis, and observed plasma ionic changes act to counteract this effect; in Sternotherus, and to a much lesser degree, Trionyx, the limitation is largely osmoregulatory, due to a failure to exclude ambient water and to maintain ionic homeostatasis.

Effect of post‐harvest treatment on the degradation of mimosine in Leucaena leucocephala leaves

AbstractThe effects of sun drying, soaking at various temperatures and submergence times, and tissue disruption on mimosine removal in Leucaena leucocephala leaves were studied. The rate of mimosine elimination increased with an increase in both temperature and exposure time, but maceration of leaves did not significantly increase the rate of mimosine conversion. Prolonged soaking of leaves was most effective, and virtually all the mimosine was degraded after 48 hours' submergence in water at 30°C.

Effect on the leaf lipids of three species of mangrove of periodic submergence in tidal water

Mangrove plant leaves of Avicennia officinalis, Acanthus illicifolius and Bruguiera gymnorhiza, grown under tidal water stress, were found to biosynthesize higher proportions of hydrocarbons, wax esters, sterol esters, triglycerides, sterols and low- M, terpenes, compared to the plants grown normally. Hydrocarbons and n-alcohols of wax esters, with longer chain lengths were found in higher proportions in the plants grown normally. Higher proportions of unsaturated n-alcohols of wax esters were present in the leaves of periodically submerged plants. Proportions of unsaturated fatty acids of wax esters, sterol esters and triglycerides were also higher in the submerged plants. Sitosterol, stigmasterol and campesterol of the sterol esters, were higher in submerged plants, whereas 28-isofucosterol was higher in normal plants. Of the free sterols, sitosterol was higher in submerged plants, whereas stigmast-7-en-3β-ol and campesterol were higher in normal plants and 28-isofucosterol was found only in submerged plants. Pentacyclic triterpenoids were found only in normal plants, whereas, the submerged plants contained low- M, terpenes in higher proportions.

Temperature Effects on the Responses to Prolonged Submergence in the Turtle Chrysemys picta bellii. I. Blood Acid-Base and Ionic Changes during and following Anoxic Submergence

Blood acid-base status and plasma ion concentrations and osmolality of freshwater turtles (Chrysemys picta bellii) were measured periodically during and following submergence in N₂-equilibrated water (Po₂ < 5 torr) at 3, 10, 15, and 20 C. Submergence durations that resulted in similar reductions in blood pH or in plasma [HCO₃⁻] at each temperature were 12 h at 20 C, 3 days at 15 C, 10 days at 10 C, and 13 wk at 3 C. At 3 C, 75% of the fall in pH during anoxia was due to metabolic acidosis, but the contribution of respiratory acidosis to the pH drop increased with temperature, being 50% at 10 C, 73% at 15 C, and 73% at 20 C. Plasma strong-ion difference decreased much less during anoxia than had been predicted on the basis of the increase in plasma lactate, owing to compensatory changes in plasma ions, including increased [K⁺], total [Ca⁺⁺], and total [Mg⁺⁺] and decreased [Cl⁻]. The magnitude of these ion changes was directly correlated with the increase in plasma lactate, which in turn was inversely correlated with temperature. Plasma lactate concentrations ranged from 96 mM at 3 C to 19.7 mM at 20 C. Recovery from anoxic acidosis at all temperatures occurred in two stages, a respiratory stage that rapidly restored blood pH and lowered blood PCo2 below control values and a slower ionic stage that corrected plasma lactate and the associated disturbances in other plasma ions. Plasma osmolality increased during anoxia, and the extent of the increase varied inversely with temperature, as did the net increase in measured plasma ions. We conclude that the prolonged tolerance to anoxia at 3 C is not due to specialized mechanisms absent at higher temperatures; rather, slow accumulation of plasma lactate, modest hypercapnia, and effective compensatory ion changes markedly retard the development of acidosis at this temperature.

Pasture seed dynamics in a dry monsoonal climate, II The effect of water availability, light and temperature on germination speed and seedling survival of Stylosanthes humilis and Digitaria ciliaris

AbstractEnvironmental factors affecting speed of germination and survival of naturally occurring seed of the legume Stylosanthes humilis and the grass Digitaria ciliaris were studied. Previous studies on the seedbed environment had shown that germination speed, defined as the proportion of seeds capable of germinating in the first 12 h period, was likely to be the most relevant laboratory measurement. Ten studies were conducted to compare species performance and to devise a standard technique for the measurement of germination speed under laboratory conditions.For S. humilis, the level and duration of submergence in water in the germination test had a large effect on germination speed (from 0–70% in 12 h). The absence of light delayed germination (7% in 12 h compared to 52% under light), but did not prevent complete germination over 7 days. Optimum temperature was 25°C with a decrease to 0% at 30°C. A standard technique was developed for measuring potential germination speed which gave reproducible results allowing differences in seed lots to be described. D. ciliaris seeds sampled just prior to field germination in the early storm period were less sensitive to environmental control. Temperature optimum for germination decreased from 40 to 30°C with the duration of the germination test. Seeds sampled at the time of seed dispersal (early dry season) had a high fraction (80%) requiring light for germination but this requirement had been lost by the early storm period.Investigations on the role of leaching (water movement) showed that long periods of water movement (12–18 h) increased the speed of germination of both species and in the case of S. humilis overcame environmental blocks to rapid germination (absence of light or 30°C temperature).Root elongation rates in S. humilis were not greatly affected by temperature over the range of seedbed temperatures when moisture is available (25–40°C) in the field. However, D. ciliaris was delayed in development at 25°C, the most likely overnight surface soil temperature. D. ciliaris was more susceptible to death by desiccation once germination had occurred compared to S. humilis. In both species seedling death due to desiccation increased with stage of development.The better relative performance of S. humilis in the germination‐establishment phase of the life cycle, which had been observed in a previous study, could be explained by a qualitative comparison of the species' attributes. This suggested that D. ciliaris was more likely to germinate at rainfall events following which there was a greater chance of seedling death

Effect of submergence on translocation, starch content and amylolytic activity in deep-water rice

Submergence induces rapid internodal elongation in deep-water rice (Oryza sativa L. cv. Habiganj Aman II). We investigated the metabolic activities which help to support such fast growth. Three days of submergence in water under continuous light led to the mobilization of 65% of the starch from those regions of rice internodes which had been formed prior to submergence. Disappearance of starch was accompanied by a 70-fold enhancement of amylolytic activity. Similar increases in amylolytic activity were detected in response to ethylene and gibberellic acid. Submergence also caused a 26-fold increase in the translocation of newly synthesized photosynthetic assimilates from the leaves to the internodes and younger regions of the culms. These physiological processes are likely to provide the metabolic energy required for internodal elongation in response to submergence.

The Comparative Physiology of Diving in North American Freshwater Turtles. II. Plasma Ion Balance during Prolonged Anoxia

Plasma ionic composition was measured during submergence in anoxic water ($P_{O_{2}} < 2 mmHg$) at 10 C of four species of North American freshwater turtles (Chrysemys picta, Chelydra serpentina, Sternotherus odoratus, and Trionyx spiniferus). As we reported in the previous paper, the species rank in the order listed in their capacity to survive prolonged anoxia at this temperature. The objectives of this study were to examine the changes in plasma ions in response to the anoxia and to relate these responses to the overall blood acid-base picture. The qualitatively similar pattern of ionic changes in each species included a primary increase in [lactate⁻] and decrease in [HCO₃⁻]. In addition, there were increases in [K⁺], total [Ca⁺⁺], and total [Mg⁺⁺] and decrease in [Cl⁻]. These latter strong ion changes are interpreted as compensatory changes that served to balance the lactate charge and that were associated with exchanges of weak ions that buffered the H⁺. The overall importance of these ionic changes ...

Effect of Submergence on the Cell Wall Composition of Deep-Water Rice Internodes

The cell wall composition of internodes of deep-water rice plants (Oryza sativa L. cv Habiganj Aman II) which were induced to grow rapidly by submergence in water was compared to that of nonsubmerged plants which grew slowly. No differences could be detected in cellulose, uronic acid, and lignin content expressed on a dry weight basis. Cell wall preparations of rapidly growing, submerged internodes contained more hydroxyproline and had a higher hydration capacity than those of control internodes. The silicon content of submerged rice internodes was considerably lower than that of air-grown plants. The role of silicon as a structural component of the cell wall of grasses is discussed in relation to lodging of deep-water rice plants after the flood waters have receded.

Regulation of growth in stem sections of deep-water rice

Submergence in water greatly stimulates internodal elongation in excised stem sections of deep-water rice (Oryza sativa L. cv. "Habiganj Aman II") and inhibits growth of leaf blades and leaf sheaths. The highest rates of internodal growth have been observed in continuous light. Very little growth occurs in submerged sections kept in darkness or incubated under N2 in the light. The effect of submergence on the growth of deep-water rice is, at least in part, mediated by C2H4, which accumulates in the air spaces of submerged sections. This accumulation results from increased C2H4 synthesis in the internodes of submerged sections and reduced diffusion of C2H4 from the tissue into the water. Increased C2H4 levels accelerate internodal elongation and inhibit the growth of leaves. Compounds capable of changing the rate of C2H4 synthesis, namely aminoethoxyvinylglycine, an inhibitor of C2H4 synthesis, and 1-aminocyclopropane-1-carboxylic acid, the immediate, precursor of C2H4, have opposite effects on growth of internodes and leaves. The enhancement of internodal elongation by C2H4 is particularly pronounced in an atmosphere of high CO2 and low O2. The increase in C2H4 synthesis in internodes of submerged sections is primarily triggered by reduced atmospheric concentrations of O2. The rate of C2H4 evolution by internodes isolated from stem sections and incubated in an atmosphere of low O2 is up to four times greater than that of isolated internodes incubated in air. In contrast, C2H4 evolution from the leaves is reduced under hypoxic conditions. The effect of submergence on growth of stem sections of deep-water rice can be mimicked by exposing non-submerged sections to a gas mixture which is similar to the gaseous atmosphere in the internodal lacunae of submerged sections, namely 3% O2, 6% CO2, 91% N2 (by vol.) and 1 μl l(-1) C2H4. Our results indicate that growth responses obtained with isolated rice stem sections are similar to those of intact deep-water rice plants.

Heart rate of the land crab Gecarcinus lateralis during aquatic and aerial respiration

1. 1. Gecarcinus lateralis were exposed to normoxic air and water environments as electrocardiograms were recorded. Heart rates average 160 beats/min in air during the first hour after electrode implantation and dropped to 87 beats/min during an hour of submergence in water. 2. 2. Bradycardia during submergence may be a response to the lower amounts of oxygen in water versus air. No compensatory tachycardia occurred when the crabs re-emerged into air, heart rate simply rapidly returned to normal. 3. 3. The bradycardia in water may indicate a decreased cardiac output. If so, it would be an important factor in the decreased oxygen extraction that is the probable cause of death during submergence.

Examination of water balance and ionic regulation in the earthworm, Eisenia foetida

1. 1. Weight change after submerging the earthworm into water varied remarkably according to the environmental humidity in which animals were placed before submergence. 2. 2. Pretreatment with physiological saline solution before submergence in water gave stable values for the ionic concentrations of the body fluid. 3. 3. Brain removal caused decrease of both sodium and chloride ion concentrations and increase of potassium ion concentration of the coelomic fluid when animals were submerged in water. 4. 4. Although brain replacement failed, action of a brain hormone is suggested to regulate the decrease of both sodium and choride ions and increase of potassium ion of the coelomic fluid to normal level when animals were submerged in water.

The cellular basis of the elongation response in submerged deep-water rice

The cellular basis of internode elongation was studied in intact deep-water rice plants (Oryza sativa L. cv. "Habiganj Aman II") and in isolated stem sections. In intact plants, growth was stimulated by submergence in water and by ethylene treatment. In isolated sections, growth was enhanced by submergence, by ethylene, and by exposure of the tissue to an atmosphere of 3% O2, 91% N2 and 6% CO2 or 3% O2, 91% N2, 6% CO2 and 1 μl l(-1) C2H4 (by vol.). Under all these conditions, growth was localized in the intercalary meristem at the bases of the internodes. Autoradiography of [(3)H]thymidine-labeled tissue showed activation of cell division and longitudinal expansion of the intercalary meristem. Increased production of new cells and their subsequent elongation thus form the basis for the growth response to submergence and ethylene treatment in deep-water rice plants.

Net Aerial Primary Production and Dynamics of Soil Organic Matter Formation in a Tidal Marsh Ecosystem

AbstractRelationships between net aerial primary production (NAPP) and soil organic matter formation in a tidal marsh environment were analyzed using a dynamic model. Four basic parameters were considered in the model: NAPP, disappearance rate of dead standing crop, and rates of plant decomposition in soil and air. The model was tested in a sawgrass (Cladium jamaicense) tidal marsh of north Florida. Net aerial primary production was estimated to be 2643 g m−2 y−1 using a paired‐plot method. The mean annual disappearance rate of dead standing crop was estimated to be 1.965 g g−1 y−1. The disappearance rate of sawgrass in soil was estimated to be 4.308 g g−1 y−1 for the labile portion and 0.105 g g−1 y−1 for the resistant portion. The sawgrass consists of 34% labile and 66% resistant portions. The soil organic matter due to NAPP was estimated to be 12.5 kg m−2. The actual soil organic matter under the marsh was found to be about 100 kg m−2. Most of the soil organic matter was preserved by constant submergence in water and, therefore, did not actively participate in the carbon cycle. Only about 20 kg m−2 of the soil organic matter that had an average thickness of 30 cm was considered to be actively participating in the carbon cycle. The dynamic model predicted 30 y is needed for soil organic matter to be stabilized, and &lt; 2 years is needed for dead standing crop to be stabilized under the environment. Ninety‐eight percent of the soil organic matter was from the resistant pool of sawgrass. The mean fraction remaining (MFR) of the soil organic matter was 0.36. Two carbon cycles were defined in the marsh soil: the short one (mean retention time = 0.73 y) is probably important to the food and energy supply of the ecosystem; the long one (mean retention time = 10 y) comprises the major portion of the soil organic matter.

Factors affecting weed seed germination and seedling growth in lowland rice in Indonesia

SummaryExperiments were carried out in Indonesia to see whether weeds of lowland rice fields could be managed by manipulation of the water table and what factors affected germination of their seeds. It was found that seeds of two Scirpus spp. germinated when buried in anaerobic soil but not when on the surface, whereas seeds of two Echinochloa spp. germinated when on the surface of both aerobic and anaerobic soils but when buried germinated only in aerobic soil.The germination of weed seeds was affected to differing extents by submergence in water at depths down to 20 cm. Germination of Fimbristylis littoralis seeds was greatly reduced and of Ludwigia hyssopifolia was complétély inhibited by submergence. Conversely, germination of Monochoria vaginalis seeds was virtually unaffected. It is suggested that the effect of submergence on germination of some species may be due to their reaction to the amplitude of temperature fluctuation. The germination and emergence of seedlings under water were greatly reduced by a cover of Salvinia molesta. The practical importance of these findings is discussed.

Salinity and waterlogging tolerance of some populations of Melaleuca ericifolia Smith

Seed germination of Melaleuca ericifolia (swamp paperbark) is delayed by submergence in water but the final percentage germination after removing seeds from water is unaffected; some seeds will germinate and the cotyledons emerge whilst submerged. Germination is totally inhibited at salinities of 14% and a population which naturally occurs adjacent to coastal saltmarsh was inhibited more by salinities of 6–12% than two other populations from freshwater habitats. Seedling growth may be increased by water‐logging conditions and the degree of response differs for different seed sources. Inundation stimulates root growth and new roots are thick and aerenchymatous. Root systems in the field run horizontally and are shallow, apparently being restricted by clay at depth. All populations studied showed a similar seedling growth‐response to salinity treatments; growth declined at salinities ≤ 13% and was severely restricted at 21%, although no seedlings died after 48 days’exposure to the latter treatment. Copyright © 1981, Wiley Blackwell. All rights reserved

Barbiturates remove apical dominance in lateral root formation in lettuce seedlings under aerobic conditions

Lateral and/or adventitious root formation do not occur in lettuce seedlings germinated on glass-distilled water in air or under submergence in glass-distilled water or barbiturate solutions. Lateral and adventitious root formation occur in lettuce seedlings germinated on barbiturates in, air and in seedlings following excision of the root apex or the entire tap root. Thus, barbiturates remove apical dominance with respect to lateral and adventitious root formation in lettuce seedlings when under aerobic conditions.

Water relations and physiological ecology of the salt marsh snail, Melampus bidentatus say

Field and laboratory studies were conducted on the water relations of the high intertidal snail Melampus bidentatus Say (Pulmonata: Ellobiidae) in the Little Sippewisset Marsh, Cape Cod (Mass., U.S.A.). Densities of Melampus in the upper 12% of the intertidal zone averaged about 1300 snails/m 2. A size gradient of snails was found, with large snails (5–12 mm shell length) occupying both upper and lower extremes of tidal height. Adult snails (>5 mm) undergo semilunar migrations, such that during neap tidal cycles the center of peak density shifts 2 m lower in the marsh from that of spring tidal cycles. Juvenile snails appear to remain in the dense vegetation of mid-range. During dry conditions in the field, snails contained 15% less body water compared with normally hydrated snails. Laboratory studies on desiccation (controlled temperature and humidity, still air) showed water loss to be inversely proportional to shell length and relative humidity (RH). Immature snails regulate water loss poorly; few survive for more than 12 h in 0–75% RH (20°C). In contrast, adults survive for 48 h or more in ⩽ 50% RH and remained alive in 97% RH for at least 14 days, despite the loss of up to 40% body water. Adult snails placed in ≈0% RH for 27–36 h were remarkably tolerant to desiccation, with an LD 50 near 80% body water loss. Melampus rehydrates rapidly when provided with free water; from a level of 50% body water loss, snails reached 90% normal water content within 0.75 h. Adult Melampus can survive submergence in sea water for at least 10 days and in fresh water for 3 days and can tolerate −12°C for several days. These studies demonstrate some of the physiological and behavioral adaptations to the rhythmicity of the tides and to the extremes in other physical factors found in the high intertidal zone. The significance of these adaptations in Melampus, and the fitting of its primitive, marine reproductive strategy to an amphibious lifestyle, are discussed in relation to the transitional status of this snail in the movement of molluscs from marine origins to land and freshwater habitats.

Heart rates of adult red-spotted newts, Notophthalmus viridescens in air and submerged in normoxic and hypoxic water at different temperatures

1. 1. Heart rates of adult aquatic red-spotted newts can be conveniently recorded using an impedance pneumograph. 2. 2. Heart rates decrease linearly with decreasing temperature. 3. 3. Submergence in normoxic and hypoxic water at 10°, 15°, and 20°C results in bradycardia which is more pronounced in hypoxic water. 4. 4. At 5°C one newt exhibited the above pattern, but bradycardia was not exhibited by the other newt during normoxic submergence. 5. 5. Diminishing heart rates are probably due to oxygen deficiency, not immersion alone. 6. 6. Recovery from bradycardia in air is rapid and not linked with resumption of aerial breathing.

The anatomy of the eye of the Adélie penguin with special reference to optical structure and intraocular musculature

Optical studies have indicated that the penguin cornea is abnormally flattened and it is suggested that this adaptation minimizes the loss of refractive power which accompanies submergence in water. Study of the gross anatomy of the eye of the Adélie penguin supports the optical results; the cornea is small in diameter and it has an abnormally large radius of curvature. Histological study of the intraocular muscles indicates that an accommodative mechanism can compensate for refractive losses in water. The ciliary muscle as well as the iris muscles are striated. Direct action by the ciliary muscle on the crystalline lens is facilitated by the presence of scleral ossicles and an annular pad around the lens. The massive size of the sphincter muscle of the iris as well as its striated appearance agrees with a suggested role for the iris sphincter in accommodation in aquatic birds.