scholarly journals Adaptations inOscillatoria redekeiat very slow growth rates—changes in growth efficiency and phycobilin complement

1987 ◽  
Vol 22 (2) ◽  
pp. 187-191 ◽  
Author(s):  
C.E. Gibson
Keyword(s):  
Growth Rates ◽  
Slow Growth ◽  
Growth Efficiency

Studies on the sowing dates of cotton in the Sudan Gezira: I. The influence of date of sowing on plant growth and development

1967 ◽  
Vol 69 (3) ◽  
pp. 305-315 ◽  
Author(s):  
J. E. Jackson
Keyword(s):  
Growth Rates ◽  
Slow Growth ◽  
Seasonal Pattern ◽  
Relative Growth ◽  
Relative Growth Rates ◽  
Research Division ◽  
Sowing Dates ◽  
Net Assimilation ◽  
State Growth ◽  
Sudan Gezira

Growth analysis of cotton crops sown in the Sudan Gezira at monthly intervals between August and May revealed a marked seasonal pattern of growth. Irrespective of plant age and fruiting state growth of non-senescent plants was slowest during the cool winter months. Relative growth rates of young plants were highest in August, September and early October due to the high specific leaf areas and fairly high net assimilation rates found then. They were lowest when minimum temperatures were lowest. Net assimilation rates were also lowest in the coolest months, probably as a result of restricted growth. High temperatures in the spring reduced fruiting. It is concluded that low minimum temperatures and high evaporation rates are both associated with slow growth, and play a large part in determining the characteristic decline of growth rates of cotton sown at the usual date in August.I wish to thank the Chief of the Research Division, Ministry of Agriculture, Sudan, for permission to publish this paper and to record my gratitude to the team of field and laboratory assistants, especially Salih Saad and Hassan Osman, who helped in the work.

Relationships Between RNA–DNA Ratio, Prey Density, and Growth Rate in Atlantic Cod (Gadus morhua) Larvae

1979 ◽  
Vol 36 (12) ◽  
pp. 1497-1502 ◽  
Author(s):  
L. J. Buckley
Keyword(s):  
Growth Rate ◽  
Nutritional Status ◽  
Growth Rates ◽  
Prey Density ◽  
Gadus Morhua ◽  
Slow Growth ◽  
Atlantic Cod ◽  
Larval Fish ◽  
Dry Weight ◽  
Dna And Rna

The protein, DNA, and RNA content of larvae maintained at 1.0 plankter/mL increased at the rates of 9.3, 9.9, and 9.8% per day, respectively, for the 5 wk after hatching. Protein reserves of larvae held at 0 or 0.2 plankters/mL were depleted by 45 and 35%, respectively, prior to death 12–13 d after hatching. Starved larvae had similar protein concentrations (percent of dry weight), lower RNA concentrations, and higher DNA concentrations than fed larvae. Larvae held at higher plankton densities had higher RNA–DNA ratios and faster growth rates than larvae held at lower plankton densities. The RNA–DNA ratio was significantly correlated (P < 0.01) with the protein growth rate. The RNA–DNA ratio appears to be a useful index of nutritional status in larval Atlantic cod (Gadus morhua) and may be useful for determining if cod larvae were in a period of rapid or slow growth at the time of capture. Key words: RNA–DNA ratio, starvation, protein, nucleic acids, growth, larval fish, Atlantic cod

scholarly journals Chromosome segregation in B. subtilis is highly heterogeneous

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Nina El Najjar ◽  
Peter L. Graumann
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Chromosome Segregation ◽  
Growth Rates ◽  
Slow Growth ◽  
Growth Conditions ◽  
Single Chromosome ◽  
Copy Numbers ◽  
Initiation Of Replication ◽  
Bacterial Cell Cycle

Abstract Objective The bacterial cell cycle comprises initiation of replication and ensuing elongation, concomitant chromosome segregation (in some organisms with a delay termed cohesion), and finally cell division. By quantifying the number of origin and terminus regions in exponentially growing Bacillus subtilis cells, and after induction of DNA damage, we aimed at determining cell cycle parameters at different growth rates at a single cell level. Results B. subtilis cells are mostly mero-oligoploid during fast growth and diploid during slow growth. However, we found that the number of replication origins and of termini is highly heterogeneous within the cell population at two different growth rates, and that even at slow growth, a majority of cells attempts to maintain more than a single chromosome at all times of the cell cycle. Heterogeneity of chromosome copy numbers may reflect different subpopulations having diverging growth rates even during exponential growth conditions. Cells continued to initiate replication and segregate chromosomes after induction of DNA damage, as judged by an increase in origin numbers per cell, showing that replication and segregation are relatively robust against cell cycle perturbation.

What drives the vital rates of secondary hemiepiphytes? A first assessment for three species of Heteropsis (Araceae) in the Colombian Amazon

2015 ◽  
Vol 31 (3) ◽  
pp. 251-265 ◽  
Author(s):  
María Paula Balcázar-Vargas ◽  
Tinde R. van Andel ◽  
Paul Westers ◽  
Pieter A. Zuidema
Keyword(s):  
Growth Rates ◽  
Vegetative Propagation ◽  
Slow Growth ◽  
Gradual Increase ◽  
Leaf Size ◽  
Stem Length ◽  
Vital Rates ◽  
Size Number ◽  
Colombian Amazon ◽  
Study Species

Abstract:Secondary hemiepiphytes rely on other plants (hosts) to grow vertically. After germinating on the forest floor, their seedlings search a host to ascend. We recorded information on survival, growth, reproduction and vegetative propagation of three Heteropsis species, to evaluate what drives their vital rates. We measured 700 individuals of each study species between 2007 and 2009 in the southern Colombian Amazon. A gradual increase in stem length, leaf size, number of roots and plagiotropic branches was found with increasing height of Heteropsis individuals on their hosts. Survival of leafless non-climbing seedlings was very low (28% annually); increasing substantially (84–94%) once the seedling had ascended a host. The three Heteropsis species presented slow height growth rates (c. 2–8 cm y−1) with large variation, while a substantial percentage of the stems (31–62%) did not grow or dried out. Vegetative propagation in Heteropsis may act as a dispersion-propagation strategy to find a suitable host and reach the canopy again after falling. The slow growth rates suggest that Heteropsis individuals that have reached the canopy are rather old. Once plants have reached the tree crowns, their longevity is largely determined by the survival of the host tree.

scholarly journals Impurity influence on normal grain growth in the GISP2 ice core, Greenland

1996 ◽  
Vol 42 (141) ◽  
pp. 255-260 ◽  
Author(s):  
R. B Alley ◽  
G. A. Woods
Keyword(s):  
Growth Rate ◽  
Grain Size ◽  
Isotopic Composition ◽  
Grain Growth ◽  
Forest Fire ◽  
Growth Rates ◽  
Slow Growth ◽  
Ice Core ◽  
Isotopic Data ◽  
Thin Sections

AbstractIntercept analysis of approximately bi-yearly vertical thin sections from the upper part of the GISP2 ice Core, central Greenland, shows that grain-size ranges increase with increasing age. This demonstrates that something in the ice affects grain-growth rates, and that grain-size cannot be used directly in paleothermometry as has been proposed. Correlation of grain-growth rates to chemical and isotopic data indicates slower growth in ice with higher impurity concentrations, and especially slow growth in “forest-fire” layers containing abundant ammonium; however, the impurity/grain-growth relations are quite noisy. Little correlation is found between growth rate and isotopic composition of ice.

Toward full, multiple, and optimal wood fibre utilization: A modeling perspective

2009 ◽  
Vol 85 (3) ◽  
pp. 377-381 ◽  
Author(s):  
Chao Li
Keyword(s):  
Forest Management ◽  
Value Creation ◽  
Growth Rates ◽  
Forest Inventory ◽  
Slow Growth ◽  
Wood Fibre ◽  
Value Chains ◽  
Modeling Framework ◽  
Global Context ◽  
Forest Managers

The slow growth rates of Canada's considerable forest fibre supply give it exceptional characteristics. It is a challenge for forest managers, researchers, and stakeholders to realize the highest value creation from this opportunity for the benefit of Canadians. Ideally, this should be achieved with full, multiple, and optimal wood fibre utilization, whereby all quality classes of wood fibre are used to their fullest potential, and all possible value creation options are considered. This paper describes the concept of value chains in a global context, and how they can be applied to forestry using a modeling framework. This is followed by a discussion on how this modeling framework can be used to address the optimal use of wood fibre, and how it can be used to address forest management-related issues and concerns. Key words: forest management, ecological modeling, wood fibre valuation, forest inventory improvement

Effects of the blood parasite Leucocytozoon simondi on growth rates of anatid ducklings

1999 ◽  
Vol 77 (10) ◽  
pp. 1573-1578 ◽  
Author(s):  
Dave Shutler ◽  
C Davison Ankney ◽  
Adele Mullie
Keyword(s):  
Growth Rates ◽  
Slow Growth ◽  
Principal Component ◽  
Blood Parasite ◽  
Wild Stock ◽  
Wild Duck ◽  
Black Duck ◽  
Size Growth ◽  
American Black ◽  
American Black Duck

The blood parasite Leucocytozoon simondi is often associated with heavy mortality of ducks and geese, especially domestic ones, in North America. In contrast, in a previous study we found no mortality from L. simondi in our wild stock of mallard (Anas platyrhynchos) and American black duck (Anas rubripes) ducklings. However, because parasites can slow growth, which could extend the interval during which ducklings are susceptible to predators, we tested for parasite effects on growth rates. We analysed growth rates over the first 20 days of life, based on tarsus length, culmen, bill width, body mass, and a principal component of structural size. Growth rates of infected ducklings were not lower than those of uninfected ducklings. Similarly, more intense infections did not have a greater effect on growth rates. Hence, growth rates were not negatively affected by L. simondi, which suggests that effects of this parasite on wild duck populations have been overestimated.

Bioenergetics of Arctic cod (Boreogadus saida) at low temperatures

1997 ◽  
Vol 54 (8) ◽  
pp. 1772-1784 ◽  
Author(s):  
H Hop ◽  
W M Tonn ◽  
H E Welch
Keyword(s):  
Energy Budget ◽  
Growth Rates ◽  
Slow Growth ◽  
Energy Content ◽  
Assimilation Efficiency ◽  
High Energy ◽  
The Arctic ◽  
Small Fish ◽  
Boreogadus Saida ◽  
Arctic Cod

The Arctic cod (Boreogadus saida), a key component of the marine food web of Canadian high Arctic waters, occurs at temperatures close to or below zero. We established a complete energy budget for this Arctic fish, based on laboratory measurements of consumption (C), growth (G), respiration (R), egestion (F), and excretion (U) at about 0°C. An average (N = 3) energy budget for individual juvenile Arctic cod fed live Arctic zooplankton was 100C = 50G + 24R + 9SDA + 3F + 6U + 8Z, where SDA is specific dynamic action (derived from previously published studies) and Z included activity and unaccounted energy. Eight determinations of total energy budgets for fish fed to satiation accounted for 72-104% of the energy consumed. Maximum daily rations and growth rates were dependent on fish size and the energy content of prey. Although maximum daily rations were similar for small fish fed different prey, diets of Calanus copepods (high energy content) resulted in faster growth rates than diets of Themisto amphipods or capelin (Mallotus villosus) fillets. Both consumption and respiration rates were low at temperatures close to 0°C. The net result was slow growth rates, although the assimilation efficiency was about 80%. Because of slow growth of individuals, the relatively high annual production of Arctic cod mainly reflects their large standing biomass.

scholarly journals Effects of temperature on individual growth rate and body size of a freshwater amphipod

1998 ◽  
Vol 76 (6) ◽  
pp. 1107-1116 ◽  
Author(s):  
Vadim E Panov ◽  
Donald J McQueen
Keyword(s):  
Growth Rates ◽  
Negative Relationship ◽  
Maximum Size ◽  
Growth Efficiency ◽  
Individual Growth ◽  
Summer Temperatures ◽  
Individual Growth Rate ◽  
Natural Temperature ◽  
Effects Of Temperature ◽  
The Relationship

Individual growth rates of the freshwater amphipod Hyalella azteca (Saussure) were measured in the littoral zone oftwo small oligotrophic Ontario lakes and in growth experiments over a natural temperature gradient (10, 15, 20, and 238C).Field observations showed that a temperature of 208C is important for both the induction and termination of reproductiveresting stages in H. azteca. Growth rates were more affected by temperature in small than in large individuals. Growthparameters are related to rearing temperature by linear regressions, which can be used as a simple model for bioenergeticscalculations in crustaceans. A negative relationship between water temperature and maximum size attained by the amphipodswas found. The largest adults were absent in studied populations when summer temperatures were high, and this phenomenon,which has also been observed in other aquatic invertebrates, was bioenergetically determined. Energy-budget estimationsshowed negative net growth efficiency (K2) in the largest adults at temperatures above 208C. The relationship between K2andtemperature showed a dome-shaped pattern, K2values for larger amphipods being maximal at lower temperatures. Seasonalmigrations of adult H. azteca from shallow littoral to deeper cold habitats, observed in lakes during the warmest periods, appearto be temperature-induced and bioenergetically advantageous, despite probable increases in predation risk experienced inspatially simple deep-water habitats.

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