scholarly journals Population growth and development of two species of Cladocera, Moina micrura and Diaphanosoma birgei, in laboratory

2002 ◽  
Vol 62 (4a) ◽  
pp. 701-711 ◽  
Author(s):  
L. H. SIPAÚBA-TAVARES ◽  
M. A. BACHION
Keyword(s):  
Water Quality ◽  
Growth Rate ◽  
Population Growth ◽  
Growth And Development ◽  
Nutritional Value ◽  
Intrinsic Rate ◽  
Dry Weight ◽  
The Other ◽  
Growth Development ◽  
Dietary Treatments

The objective of the present work was to investigate the influence of four diets on population growth, development, total length, dry weight, and nutritional value of two zooplanktonic species, Moina micrura and Diaphanosoma birgei. The four dietary treatments were: algae alone (A); algae + vitamins (AV); algae + ration (AR); and algae + ration + vitamins (ARV). Growth rate peak for both species occurred faster with AV treatment. In general, AV treatment for M. micrura showed better results for intrinsic rate, fecundity, and embryonic and post-embryonic development. On the other hand, longevity and total spawning number were better with AR treatment (p < 0.05). Vitamin and ration treatments produced the best results in D. birgei species (p < 0.05). The highest percentage of protein and lipids for both cladocerans was verified for ration treatments. Carbohydrate was higher for the treatment containing algae alone (p < 0.05). Generally, diets containing ration and vitamin showed better results in cladocerans development, with water quality adequate for culture systems. Ration and vitamin diets may also be used in high-density cultures in the laboratory.

Growth and Development of Organic Arsenical-Susceptible and -Resistant Common Cocklebur (Xanthium strumarium) Biotypes Under Noncompetitive Conditions

1994 ◽  
Vol 8 (1) ◽  
pp. 154-158 ◽  
Author(s):  
William E. Haigler ◽  
Billy J. Gossett ◽  
James R. Harris ◽  
Joe E. Toler
Keyword(s):  
Growth Rate ◽  
Leaf Area ◽  
Plant Height ◽  
Growth And Development ◽  
Reproductive Potential ◽  
Dry Weight ◽  
Growing Season ◽  
Xanthium Strumarium ◽  
Relative Growth ◽  
Growth Development

The growth, development, and reproductive potential of several populations of organic arsenical-susceptible (S) and -resistant (R) common cocklebur biotypes were compared under noncompetitive field conditions. Plant height, leaf area, aboveground dry weights, and relative growth rate (RGR) were measured periodically during the growing season. Days to flowering, bur dry weight, and number of burs per plant were also recorded. Arsenical S- and R-biotypes were similar in all measured parameters of growth, development, and reproductive potential. Populations within each biotype varied occasionally in plant height, leaf area, aboveground dry weights, and reproductive potential.

scholarly journals THE GROWTH AND ABSORPTION OF NUTRIENTS BY FERTILIZED AND UNFERTILIZED WHITE SPRUCE SEEDLINGS

1966 ◽  
Vol 42 (2) ◽  
pp. 127-136 ◽  
Author(s):  
K. A. Armson
Keyword(s):  
Growth Rate ◽  
Growth And Development ◽  
Dry Weight ◽  
Growing Season ◽  
White Spruce ◽  
Height Growth ◽  
Relative Growth ◽  
Uptake Rates ◽  
Abrupt Changes ◽  
Growth Development

A study was made of the effects of fertilizer additions on the growth and development of white spruce seedlings during their second growing season. In terms of dry weight increment, unfertilized trees grew for only two-thirds of the total growing season available as compared with fertilized trees. The relative growth rate curve for the fertilized trees was smooth with none of the abrupt changes which marked the curve for the unfertilized trees. The pattern of height growth was changed for seedlings which were fertilized. Nutrient uptake rates particularly for phosphorus were different under the two treatments and it is suggested that these differences were related to different patterns of height growth development and root extension.

Demography of an Estuarine Amphipod (Gammarus lawrencianus) Experimentally Selected for High "r": A Model of the Genetic Effects of Environmental Change

1981 ◽  
Vol 38 (9) ◽  
pp. 1120-1127 ◽  
Author(s):  
R. W. Doyle ◽  
W. Hunte
Keyword(s):  
Growth Rate ◽  
Population Growth ◽  
Life History Strategy ◽  
Intrinsic Rate ◽  
Individual Growth ◽  
Population Growth Rates ◽  
Phenotypic Correlations ◽  
Demographic Traits ◽  
Marine Crustacean ◽  
Individual Growth Rate

The estuarine amphipod Gammarus lawrencianus was subjected to prolonged selection (3 years; 26 generations) for high population growth rates. The demography of the selected population was studied in detail and compared under laboratory conditions with animals derived from a control (wild) population collected in the same area 3 years later. In the lab-adapted population the intrinsic rate of population growth r increased by 72% as the result of changes in age at maturation, survivorship, and fecundity. The variance of these traits decreased and Crow's (1958) index of total selection (variance of fitness/mean fitness squared) is proposed as a quantitative and operational measure of genetic adaptation to a changed environment. Possible limitations on adaptation were investigated by examining the correlations among demographic traits within the lab-adapted population. Some phenotypic correlations were determined directly and others by an indirect technique using information from full siblings. Individual growth rate was negatively correlated both with survival and fecundity. Individual growth rate and age at sexual maturity were also negatively correlated. Negative phenotypic correlations between traits may indicate limitations on long-term adaptation. We conclude that significant evolutionary changes in the demographic traits of this (and presumably other) marine crustacean can occur within a time scale of interest to ecologists and aquaculturalists.Key words: adaptation, amphipod, aquaculture, Crustacea, evolution, Gammarus, genetics, life history, strategy

Effects of parasitization by the insect parasite Hyposoter exiguae on the growth, development and physiology of its host Trichoplusia ni

Parasitology ◽  
1982 ◽  
Vol 84 (3) ◽  
pp. 491-510 ◽  
Author(s):  
S. N. Thompson
Keyword(s):  
Growth Rate ◽  
Weight Gain ◽  
Growth And Development ◽  
Trichoplusia Ni ◽  
Fat Body ◽  
Weight Ratio ◽  
Juvenile Hormone Esterase ◽  
Insect Parasite ◽  
Wet Weight ◽  
Growth Development

SummaryThe weight gain and growth rate of Trichoplusia ni larvae were severely depressed following parasitization by the insect parasite, Hyposoter exiguae. The development of the host was also delayed and juvenile hormone esterase activity present at the normal time of moulting was absent in parasitized insects. Similar effects on growth and development were achieved by rearing host insects on nutrient-deficient media. Accompanying the above effects of parasitization were alterations in dry/wet weight ratio and host haemolymph osmolality. Parasitization resulted in immediate increases in the concentrations of haemolymph non-glycogen carbohydrate (composed of trehalose, maltose and glucose) and protein. The concentration of fat body glycogen also increased following parasitization. In contrast, the concentration of haemolymph non-glycogen carbohydrate and protein, as well as fat body glycogen, decreased in nutrient-deprived larvae. The significance of the above results as they relate to the insect parasite–host relationship is discussed.

Interaction between competitors and predators and its effects on morphological and behavioural defences in Scinax nasicus tadpoles

Behaviour ◽  
2013 ◽  
Vol 150 (8) ◽  
pp. 921-937 ◽  
Author(s):  
Valeria I. Gómez ◽  
Arturo I. Kehr
Keyword(s):  
Growth Rate ◽  
Experimental Design ◽  
Growth And Development ◽  
Chemical Cues ◽  
Development Rate ◽  
Larval Morphology ◽  
Induced Defences ◽  
Morphological Defences ◽  
Growth Development ◽  
Determinant Factor

Predation affects the behaviour of organisms, and the number of conspecifics can influence the perception of predation risk. Two main types of traits, morphological and behavioural, are involved in the induced defences of many organisms. Here, we examined the influence of chemical cues of the predators Belostoma elongatum (Hemiptera, Belostomatidae) and Moenkhausia dichroura (Characiformes, Characidae) on the morphology, growth, development and activity of Scinax nasicus larvae. Our main goal was to determine whether the investment in morphological or behavioural defences varied according to the number of conspecifics and to the chemical cues of predators. To this end, we performed two experiments under microcosm conditions. In experiment 1, we determined morphological defences in tadpoles by analysing changes in morphology, growth rate and development rate, whereas in experiment 2, we determined behavioural defences by analysing changes in the activity of tadpoles. The experimental design consisted of two tadpole densities, with and without chemical cues of predators. We found that: (1) larval morphology, growth and development were significantly affected by density; (2) the chemical cues of the predators did not influence the morphology, growth or development of tadpoles; (3) tadpoles at high densities were more active than those at low densities; (4) tadpoles decreased the activity in the presence of chemical cues of M. dichroura; and (5) tadpoles increased the activity in the presence of chemical cues of B. elongatum. Our results suggest that density is a determinant factor of tadpole morphology of and that Scinax nasicus larvae respond to predators with behavioural defences, which vary according to the type of predator.

scholarly journals DYNAMIC LAFFER CURVES AND POPULATION GROWTH

2021 ◽  
Author(s):  
Shumaila Waqas
Keyword(s):  
Growth Rate ◽  
Population Growth ◽  
Dynamic Effect ◽  
Budget Constraint ◽  
The Other ◽  
Tax Revenue ◽  
Tax Base ◽  
Intertemporal Budget Constraint ◽  
Other Hand ◽  
Opposing Effects

This paper extends the model of Ireland (1994) by incorporating population growth in examining the dynamic effects of a tax cut on the government’s intertemporal budget constraint. A tax cut has two opposing effects. First, it increases the growth rate of the economy and, thus, increases the size of the tax base and tax revenues in the future. On the other hand, a reduction in the tax rate leads to a decrease in revenues in the short run. A dynamic Laffer curve effect arises if a decrease in tax revenue can be counter-balanced by a future increase in tax revenue to ensure that the government’s intertemporal budget constraint is not violated. Similarly, population growth has two opposing effects. A high population growth decreases the per capita growth rate of the economy. On the other hand, a larger population represents a larger tax base and, therefore, makes it easier for a government to finance a budget deficit. Relative to the simulation results in Ireland (1994), our simulations indicate that incorporating population growth into his model implies that the dynamic effect of a given tax cut worsens the government’s long-run fiscal outlook.

scholarly journals The evolution of the concepts of growth, development and other related, during the last decades

2014 ◽  
Vol 58 (3) ◽  
pp. 439-465
Author(s):  
Leszek S. Jankiewicz
Keyword(s):  
Growth Hormone ◽  
Growth Regulator ◽  
Growth And Development ◽  
The Other ◽  
Chemical Basis ◽  
Graphic Form ◽  
Growth Development ◽  
Traditional Term

The evolution of such terms as growth, differentiation, development, morphogenesis etc. is discussed. It is proposed that the term (notion) development should be understood to comprise "growth", "differentiation" and even "abscission, abortion and necrosis". The term "development" is already used in such a way by some authors. The relations among the phenomena denoted by the above terms are presented in a graphic form to show that they partly overlap. The concept that growth and development represent quantitative and qualitative aspects (respectively) of plant augmentation is criticized. The newly introduced terms "development hormone" or "development regulator" seem more suitable than "growth hormone" and "growth regulator", however, these later ones are correct and may be used. The traditional term "phytohormone" and the newly introduced one "phytoregulator" seem convenient, but it must be kept in mind that such substances may transmit information both on a chemical basis as well as on a biophysical one. An example here can be auxin; a change in the wavy character of its transport may serve as information. In some cases a complex of two or more substances may play the role of a hormone, for instance ACC and ethylene, of which one is easily transportable but little active and the other is very active but exerts its action rather locally. Other combinations of activities may exist in other such pairs.

Development of yield in two grain-sorghum hybrids. I. Dry weight and carbon-14 studies

1982 ◽  
Vol 33 (6) ◽  
pp. 1009 ◽  
Author(s):  
RJ Chamberlin ◽  
GL Wilson
Keyword(s):  
Growth Rate ◽  
Grain Yield ◽  
Grain Growth ◽  
Growth And Development ◽  
Dry Weight ◽  
Grain Sorghum ◽  
Carbon 14 ◽  
Biological Yield ◽  
Total Dry Weight ◽  
Weight Data

Growth and development of two grain-sorghum hybrids (De Kalb E57 and Texas 610) were examined under glasshouse conditions by sequential harvesting and the use of I4C. The grain yield per plant of Texas 610 was higher than that of E57, with higher total biological yield and similar harvest indices. The contribution to grain weight at maturity, of carbon assimilated prior to anthesis, was about 10% for each hybrid. The leaves were the main source of this material. After anthesis, dry weight data indicated that temporary storage of assimilates before retranslocation to the grain was of greater importance in Texas 610 than E57. This storage was largely in the leaves (including sheaths), upper internodes, and roots. A high grain-growth rate was maintained for longer by Texas 610 than by E57. Total dry weight production after anthesis in both hybrids was, at all stages examined, more than sufficient to maintain grain growth.

scholarly journals The effect of growth and development intensity in replacement heifers on economically important traits of Holstein cattle in the Czech Republic

2008 ◽  
Vol 52 (No. 9) ◽  
pp. 277-283 ◽  
Author(s):  
J. Bouška ◽  
M. Štípková ◽  
M. Krejčová ◽  
L. Bartoň
Keyword(s):  
Growth Rate ◽  
Weight Gain ◽  
Growth And Development ◽  
Live Weight ◽  
The Other ◽  
Total Production ◽  
Live Weight Gain ◽  
Productive Life ◽  
Reproduction Traits ◽  
The Relationship

The objective of the study was to determine the effect of growth and development intensity in Holstein replacement heifers on economically important animal traits. The intensity of growth was assessed by the average live weight gain until 14 months of age. In addition, live weight and height at the sacrum at 14 months of age were analysed as indicators of growth and development when evaluating the length of productive life. The milk yield of first-calvers increased as the average daily live weight gain in the rearing period increased. An opposite tendency was recorded for cows in their second and third lactation and the total production also decreased with a higher growth rate of heifers. The analysis of the relationship between growth rate and the following reproduction traits revealed that the increased average daily live weight gain to 14 months was subsequently associated with reduced reproduction efficiency in cows. The differences between the groups with the lowest and the highest average live weight gains in the number of days open in the first and second calving interval were 26.78 and 17.47 days, respectively. This tendency was also confirmed in the other reproduction traits analysed. Productive life was significantly longer in animals with the lowest intensity of growth and development compared to the other groups (2.17 to 5.49 months, <i>P</i> < 0.01).

scholarly journals Population Dynamics, Fecundity and Fatty Acid Composition of Oithona nana (Cyclopoida, Copepoda), Fed on Different Diets

Animals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1188
Author(s):  
Fawzy I. Magouz ◽  
Mohamed A. Essa ◽  
Mustafa Matter ◽  
Abdallah Tageldein Mansour ◽  
Mohamed Alkafafy ◽  
...  
Keyword(s):  
Growth Rate ◽  
Fatty Acid Composition ◽  
Fatty Acid ◽  
Population Growth ◽  
Acid Composition ◽  
Rice Bran ◽  
Nutritional Value ◽  
Corn Starch ◽  
Copepod Species ◽  
Marine Copepod

The marine copepod species Oithona nana is considered as one of the most successfully mass cultured Cyclopoida species in marine hatcheries. This study investigated the effects of four feed diets (soybean, yeast, rice bran, and corn starch) on the population growth, growth rate, population composition, fecundity, and fatty acid composition of native isolated Cyclopoida copepod species O. nana. The experiment was continued for 15 days and the copepods were fed on one of the four diets with a concentration of 1 g 10−6 individual day−1. The results revealed that corn starch was found to be the most supportive diet for population growth and population growth rate. For nutritional value, copepods fed on rice bran were detected to have the highest content of MUFA, PUFA, and the lowest SFA and SFA/UFA ratio; more importantly, the rice bran diet was the only treatment that showed C20:5ω3. Moreover, copepods fed on rice bran showed the highest significant female fecundity, copepodite, and nauplii percent. Finally, the protocols described in the current study concluded that the dry feeds, especially corn starch, are very useful and applicable in hatcheries for maximizing the fecundity and density of Cyclopoida copepod species, O. nana.

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