Rates of growth of the food fungus of the leaf-cutting ant Atta cephalotes (L.) (Hymenoptera: Formicidae) on different substrates gathered by the ants

1979 ◽  
Vol 69 (1) ◽  
pp. 141-148 ◽  
Author(s):  
A. Mudd ◽  
G. L. Bateman
Keyword(s):  
Nutrient Availability ◽  
Plant Material ◽  
Growth Inhibitors ◽  
Atta Cephalotes ◽  
Leaf Extracts ◽  
Relative Growth ◽  
Relative Growth Rates ◽  
Foraging Preferences ◽  
Leaf Cutting ◽  
Rates Of Growth

AbstractGrowth of the food fungus of the leaf-cutting ant Atta cephalotes (L.) on extracts of plants selected by the ants was shown to be affected by the plant species, the pH of the extract, the concentration of the sap or plant extract and pretreatment of the substrate by the ants. It was not possible to establish an unambiguous relationship between the rate of growth of the fungus on leaf extracts and the foraging preferences of the ants for the leaves. There were indications, however, that the fungus grows most rapidly on extracts of plant material preferred by A. cephalotes. Relative growth rates of the fungus on different substrates may be related to the presence of growth inhibitors rather than to nutrient availability.

The Relative Growth of Parts in Palaemon Carcinus

1930 ◽  
Vol 7 (2) ◽  
pp. 165-174
Author(s):  
M. A. TAZELAAR
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
Linear Measurements ◽  
Relative Growth ◽  
Male And Female ◽  
Relative Growth Rates ◽  
Rate Of Growth ◽  
The Difference ◽  
Rates Of Growth

Linear measurements of certain appendages and the carapace of P. carcinus were made and plotted in various ways. The following conclusions were drawn: 1. The cheliped shows heterogonic growth in both male and female, but more markedly in the male, the values of k being: male 1.8 and female 1.48 2. The pereiopods in both male and female are slightly heterogonic. The relative growth rates are graded from p3 to p5, that of p3 being slightly greater than that of p5 3. Of the ordinary pereiopods the rate of growth of p1 is the smallest in the male, but the largest in the female. 4. The difference between the rates of growth of p1 and p3 in male and female is greatest where the rate of growth in the heterogonic organ, the cheliped, is most excessive in the male. 5. The growth of the 3rd maxilliped is slightly negatively heterogonic, the value of k in the male being 0.93 and in the female 0.95. Hence there seems to be a correlation between the marked heterogony in the cheliped on the growth rate of neighbouring appendages. In those immediately posterior to the cheliped the growth rate is increased and in those anterior decreased.

Competition affects shoot morphology, growth duration, and relative growth rates of Douglas-fir saplings

1991 ◽  
Vol 21 (4) ◽  
pp. 474-481 ◽  
Author(s):  
Timothy B. Harrington ◽  
John C. Tappeiner II
Keyword(s):  
Basal Area ◽  
Douglas Fir ◽  
Morphological Parameters ◽  
Growth Duration ◽  
Relative Growth ◽  
Relative Growth Rates ◽  
Growing Seasons ◽  
Forest Sites ◽  
Bud Size ◽  
Rates Of Growth

Saplings of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco var. menziesii) were grown with and without competition from tanoak (Lithocarpusdensiflorus (Hook. & Arn.) Rehd.) at two forest sites in southwestern Oregon. Competition reduced the following morphological parameters on Douglas-fir shoots: number and size of buds; lengths of shoots, internodes, and needles; number of internodes; and biomass of foliage and wood. Differences in the length and biomass of Douglas-fir shoots were attributed to combined reductions in internode number and internode length (distance between needles), with internode number accounting for most (72–87%) of the variation. The effects of competition from previous years on Douglas-fir growth, as manifested in 1986 bud size or stem circumference, explained 65 and 92% of the variation in 1987 growth of shoots and stem basal area, respectively. The current-year (1987) effects of competition explained an additional 6 and 3%. During the 1986 and 1987 growing seasons, competition limited both the rates and duration of growth of Douglas-fir basal area; for height, only the rates of growth were reduced.

Direct ingestion of plant sap from cut leaves by the leaf-cutting ants Atta cephalotes (L.) and acromyrmex octospinosus (reich) (Formicidae, Attini)

1976 ◽  
Vol 66 (2) ◽  
pp. 205-217 ◽  
Author(s):  
M. Littledyke ◽  
J. M. Cherrett
Keyword(s):  
Plant Material ◽  
Atta Cephalotes ◽  
Fungus Garden ◽  
Acromyrmex Octospinosus ◽  
Substrate Preparation ◽  
Fungus Culture ◽  
Large Numbers ◽  
Leaf Cutting ◽  
Laboratory Colonies ◽  
Reduced Drinking

AbstractIngestion of radiolabelled plant juices from cut surfaces of leaves during foraging and during substrate preparation for the fungus garden was demonstrated for laboratory colonies of the leaf-cutting ants Atta cephalotes (L.) and Acromyrmex octospinosus (Reich). Using P32 isotope, up to one-third of the radioactivity in the leaves was taken in directly by the colony as a whole, but this was much less when C14 was used. Additional plant material was taken in by the ants via the fungus garden. Large numbers of ants spend time in investigating cut surfaces of leaves and also in cutting and crimping leaves. Ingestion of plant material during these processes could play an important nutritional role in the colony and this may explain why many ants return from foraging apparently unladen. Large ants obtained most of their plant juice intake during foraging and the medium and small ants took much of theirs during substrate preparation. Inhibitory chemicals did not affect cutting but they reduced drinking and also reduced the intake of P32 from leaves during substrate preparation. The ants also ingested different amounts of P32 from leaves of different acceptability. It is suggested that leaf-cutting ants use fungus culture as a means of ‘sidestepping’ plant inhibitors. Nutrients are ingested directly from leaves when these are palatable, and the less palatable components are made available to the ants via the fungus.

Ecological Differentiation Between Species of Scribbly Gums [Eucalyptus Informal Subseries Haemastominae (MATK) Prior & Johnson] and Angophora in Seedling Responsiveness to Mineral Nutrients

1983 ◽  
Vol 31 (6) ◽  
pp. 645 ◽  
Author(s):  
J Mowatt ◽  
PJ Myerscough
Keyword(s):  
Leaf Area ◽  
Nutrient Availability ◽  
Growth Rates ◽  
Nutrient Supply ◽  
Natural Soils ◽  
Relative Growth ◽  
Relative Growth Rates ◽  
Nutrient Levels ◽  
Mean Relative Growth Rate ◽  
Infertile Soils

When four species of scribbly gums (Eucalyptus subseries Haemastominae) and four species of Angophora, together with Eucalyptus pilularis, were grown in a range of nutrient levels from distilled water to full Hoagland's nutrient solution, the two groups reacted differently, reflecting their contrasting distributions in relation to soil fertility. Their mean relative growth rates were similar, but the magnitude of the response to increasing nutrient availability varied among the angophoras although it was very similar for all the scribblies. The degree of response of the angophoras was correlated with the fertility of their natural soils: A. floribunda, coming from the most fertile soils, showed the greatest response in mean relative growth rate to increasing nutrient supply. Specific leaf areas did not vary among nutrient levels but, as with mean relative growth rates, the angophoras showed a correlation between the fertility of their natural soils and the specific leaf area: A. hispida, from the least fertile soils, developed the thickest leaves. The angophoras differed from each other in leaf area ratio whereas the scribblies did not. This characteristic was influenced by nutrient availability: the angophoras growing at the higher levels of nutrient supply developed greater leaf areas ratios. There was little difference among the four scribbly gum species in their response to nutrients. They all occur on infertile soils and showed little response to increased nutrient supply.

A Measure of Economic Growth in East and in West Pakistan

1961 ◽  
Vol 1 (2) ◽  
pp. 49-54
Author(s):  
S. U. Khan
Keyword(s):  
Regional Planning ◽  
National Income ◽  
Future Planning ◽  
Correct Evaluation ◽  
Relative Growth ◽  
Relative Growth Rates ◽  
National Planning ◽  
Income Data ◽  
Regional Basis ◽  
The Difference

It is sometimes said that "national planning will simply have no meaning if it completely ignores the economic disparities between the two wings and fails to evolve a sensible pattern of regional planning"2. The lack of much essential data on a regional basis, however, renders any precise estimate of the relative growth rates almost impossible. Data either are not available or are inadequate on such important variables as production, income, consumption and trade, so that even a correct evaluation of past development efforts is not possible. The implications of such a situation for future planning are not difficult to understand. In this article an attempt is made to estimate the absorption of specified commodities in East and West Pakistan separately3. This will indicate the pattern of consumption and also give a rough idea about the growth rate of the two wings. With this purpose in view, quantity indices of absorption are prepared for each wing separately, taking data on availability of goods and prices from the Institute's monograph on Inflation. The quantity indi¬ces, however, are not of course strictly comparable with national income estimates because of the difference in coverage of the two series. National income data include government, services, trade, etc., while the quantity indices cover only specified goods available for each region.

CHANGES IN ENZYMES AND PROTEINS IN SALT-SHOCKED VS. GRADIENT INCREASES IN NACL IN `POINSETT' CUCUMBER ROOTS

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1091G-1091
Author(s):  
Anne K. Hurley ◽  
B. Greg Cobb
Keyword(s):  
Invertase Activity ◽  
Shock Treatment ◽  
Cucumis Sativus L ◽  
Relative Growth ◽  
Relative Growth Rates ◽  
Salt Shock ◽  
Gradient Solution ◽  
Cucumber Roots ◽  
Average Plant ◽  
Plastochron Index

Cucumis sativus, L., `Poinsett' seedlings were grown under artificial light in 40% modified Hoagland's solution until an average plant plastochron index of 4.73 was reached. Plants were then placed in solutions of (1) 0 mM NaCl, (2) 80 mM NaCl (salt-shock), or (3) placed in a dropwise gradient solution of NaCl and Hoagland's until the final concentration of 80 mM NaCl was reached at 41 hours. Leaves of the 80 mM shock treatment wilted immediately, but recovered turgor within 6 hours. Leaves of 80 mM gradient did not wilt at anytime. The control and gradient treatments had relative growth rates which were similar to each other, but RGR decreased in the shock treatment. Invertase activity was measured in the roots at 24, 41, and 48 hours after initial treatment. Invertase activity of shock treatment increased significantly over the controls at 24 hours. The 80mM gradient was not significantly different than either treatment. Four isozymes of α– galactosidase were detected. The relative intensities of the bands varied with time and treatment. One invertase band was resolved in roots on 8% native acrylamide gels. SDS gels indicated increases in proteins in the gradient treatment compared to the control and the 80 mM shock treatment.

Traffic Dynamics of the Leaf-Cutting Ant, Atta cephalotes

2002 ◽  
Vol 159 (3) ◽  
pp. 283
Author(s):  
Burd ◽  
Archer ◽  
Aranwela ◽  
Stradling
Keyword(s):  
Atta Cephalotes ◽  
Traffic Dynamics ◽  
Leaf Cutting

Selection for biomass production based on respiration parameters in eucalypts: effects of origin and growth climates on growth rates

1996 ◽  
Vol 26 (9) ◽  
pp. 1556-1568 ◽  
Author(s):  
Thimmappa S. Anekonda ◽  
Richard S. Criddle ◽  
Lee D. Hansen ◽  
Mike Bacca
Keyword(s):  
Temperature Dependence ◽  
Growth Rates ◽  
Heat Rate ◽  
Eucalyptus Species ◽  
Relative Growth ◽  
Relative Growth Rates ◽  
Metabolic Heat ◽  
Respiratory Parameters ◽  
Metabolic Heat Rate ◽  
Different Climates

Seventeen Eucalyptus species and 30 rapid-growing Eucalyptuscamaldulensis trees (referred to as plus trees), growing in a plantation were studied to examine relationships among measured plant growth and respiratory parameters, geographical origins, and growth climate. The respiratory parameters measured at two different temperatures by isothermal calorimetry were metabolic heat rate, rate of CO2 production, and the ratio of heat rate to CO2 rate. Metabolic heat rate was also measured as a continuous function of temperature by differential scanning calorimetry in the range of 10 to 40 °C. Tree growth was measured as rates of height and stem volume growth. The values of respiratory and growth variables of Eucalyptus species are significantly correlated with latitude and altitude of origin of their seed sources. The maximum metabolic heat rate, the temperature of the maximum heat rate, the temperature coefficients of metabolic rate, and the temperatures at which the slopes of Arrhenius plots change are all genetically determined parameters that vary both within and among species. Measurement of growth rate–respiration rate–temperature relationships guide understanding of why relative growth rates of Eucalyptus species and individual genotypes differ with climate, making it possible to identify genotypes best suited for rapid growth in different climates. The temperature dependence of respiration rates is an important factor determining relative growth rates of eucalypts in different climates. To achieve optimum biomass production the temperature dependence of individual plants must be matched to growth climate.

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.

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