A Comparison of Relative Growth Rates of Different Individual Plants and Different Cultivars of Onion of Diverse Geographic Origin at Two Temperatures and Two Light Intensities

1981 ◽  
Vol 18 (2) ◽  
pp. 589 ◽  
Author(s):  
J. L. Brewster ◽  
A. Barnes
Keyword(s):  
Growth Rates ◽  
Geographic Origin ◽  
Relative Growth ◽  
Relative Growth Rates ◽  
Light Intensities ◽  
Two Temperatures

A Comparison of the Respiratory Processes and Growth Rate of Selected Australian Alpine and Related Lowland Plant Species

1990 ◽  
Vol 17 (5) ◽  
pp. 517 ◽  
Author(s):  
OK Atkin ◽  
DA Day
Keyword(s):  
Growth Rates ◽  
Alternative Oxidase ◽  
Geographical Origin ◽  
Relative Growth ◽  
Relative Growth Rates ◽  
Alternative Pathways ◽  
Respiration Rates ◽  
Whole Plant ◽  
Two Temperatures ◽  
Plant Respiration

Respiratory processes and growth rates of alpine and lowland species of three genera (Ranunculus, Plantago and Luzula) were compared. Relative growth rates were determined for the first 14 weeks of growth at two temperatures (7-10°C and 12-15°C). Generally, the relative growth rates of the alpine species were lower than those of their lowland relatives. Whole-plant respiration rates were measured and leaf slices from each species were used for a detailed analysis of respiratory pathways. Major differences were found between genera, particularly in their alternative oxidase activity, but respiratory patterns (both whole-plant respiration rates and the relative rates of cytochrome and alternative pathways in leaf slices) were maintained within a given genus, independent of the environmental or geographical origin of each species from that genus. The lack of correlation between growth rates and respiration rates suggests that the alpine plants used their respiratory products less efficiently than did the lowland species.

scholarly journals Effects of light on the growth and photosynthesis of Egeria najas planchon

2003 ◽  
Vol 46 (2) ◽  
pp. 203-209 ◽  
Author(s):  
Washington Luiz Gomes Tavechio ◽  
Sidinei Magela Thomaz
Keyword(s):  
Root Growth ◽  
Growth Rates ◽  
Low Light ◽  
Light Requirement ◽  
Relative Growth ◽  
Relative Growth Rates ◽  
Light Compensation Point ◽  
Light Intensities ◽  
Light Requirements ◽  
Egeria Najas

Photosynthesis and growth of Egeria najas (Hydrocharitaceae) from a subtropical reservoir (Itaipu Reservoir, Brazil-Paraguay) were measured in response to low light intensities (0-124 µM m-2 s-1 PAR) in the laboratory. Photosynthesis approached saturation in the range of light intensities used and light compensation point was reached at ca. 6-22 µM m-2 s-1 PAR, indicating that this species had a low light requirement for growth. Light stimulated shoot and root relative growth rates (RGR) but it was not related to ratios between root:shoot RGR. Laboratory observations indicated that (i) both shoot and root growth were simultaneously stimulated by light and (ii) the low light requirements of E. najas may explain its incidence in the Itaipu Reservoir, where biogenic as well as abiogenic turbidity is high.

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.

The effect of barley yellow dwarf virus on early plant growth in ryegrass (Lolium spp.)

1989 ◽  
Vol 40 (2) ◽  
pp. 293 ◽  
Author(s):  
DR Eagling ◽  
RJ Sward ◽  
GM Halloran
Keyword(s):  
Leaf Area ◽  
Growth Rates ◽  
Barley Yellow Dwarf Virus ◽  
Dry Weight ◽  
Relative Growth ◽  
Relative Growth Rates ◽  
Root Dry Weight ◽  
Shoot Dry Weight ◽  
Barley Yellow Dwarf ◽  
Yellow Dwarf Virus

Measurements were made on the effect of barley yellow dwarf virus (BYDV) infection on the early growth of four commercial cultivars of ryegrass (Lolium spp.) under two different temperatures (24�C and 16�C). At 24'C, BYDV infection was associated with reduced root dry weight (30-40%) in all cultivars; the effect of infection on shoot dry weight and leaf area was variable. At 16�C, the effect of BYDV infection was variable, being associated with increases in root dry weight, shoot dry weight, and leaf area in one cultivar (Grasslands Ariki) and decreases in another (Victorian). In two other cultivars, root dry weight, shoot dry weight and leaf area were not significantly affected (P>0.05) by infection with BYDV.At 24�C, the reductions in root dry weight associated with BYDV infection were not concomitant with reductions in the root relative growth rates. Up to at least 28 days after inoculation (46-50 days after germination) reductions in root dry weight were associated with both aphid-feeding damage and virus infection. Experiments with the cultivar Victorian, showed that shoot dry weight was not significantly affected (P>0.05) by feeding with viruliferous (BYDV) or non-viruliferous aphids (Rhopalosiphum padi L.). At 16�C, changes in root and shoot dry weight were associated with changes in the root and shoot relative growth rates.

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