scholarly journals Elevated Atmospheric CO2 Magnifies Intra-specific Variation in Seedling Growth of Honey Mesquite: An Assessment of Relative Growth Rates

2006 ◽  
Vol 59 (2) ◽  
pp. 128-134 ◽  
Author(s):  
H. Wayne Polley ◽  
Charles R. Tischler ◽  
Hyrum B. Johnson
Keyword(s):  
Seedling Growth ◽  
Growth Rates ◽  
Atmospheric Co2 ◽  
Relative Growth ◽  
Relative Growth Rates ◽  
Elevated Atmospheric Co2 ◽  
Specific Variation ◽  
Honey Mesquite

Dormancy, germination and seedling growth of two Kalaharian perennials of the genus Harpagophytum (Pedaliaceae)

1988 ◽  
Vol 4 (2) ◽  
pp. 185-198 ◽  
Author(s):  
W. H. O. Ernst ◽  
T. Tietema ◽  
E. M. Veenendaal ◽  
R. Masene
Keyword(s):  
Gibberellic Acid ◽  
High Temperatures ◽  
Seedling Growth ◽  
Seed Coat ◽  
Growth Rates ◽  
Natural Conditions ◽  
Relative Growth ◽  
Relative Growth Rates ◽  
Respiration Rates ◽  
Drought Avoidance

ABSTRACTDormancy and germination ecology of two Harpagophytum species (Pedaliaceae) from an open Acacia savanna in Botswana were investigated. The maintenance of dormancy is governed partly by the seed coat but mainly by the endosperm and the embryo itself, as demonstrated by removal of the endosperm. Dissemination of the seed from the fruit can be delayed for several years without affecting the viability of the embryo, due to very low respiration rates.Germination can be enhanced slightly by high temperatures under natural conditions, and by gibberellic acid or removal of the endosperm under laboratory conditions. Relative growth rates for both Harpagophytum species are lower than for subtropical grasses and legumes, due to a strong investment in root and tuber biomass. Germination and seedling growth is discussed in relation to the drought avoidance syndrome and the animal disperser syndrome.

Seedling growth responses to water and nutrient augmentation in the understorey of a lowland moist forest, Panama

2008 ◽  
Vol 24 (1) ◽  
pp. 19-26 ◽  
Author(s):  
Joseph B. Yavitt ◽  
S. Joseph Wright
Keyword(s):  
Seedling Growth ◽  
Growth Rates ◽  
Height Growth ◽  
Dry Season ◽  
Wet Season ◽  
Soil Resources ◽  
Relative Growth ◽  
Relative Growth Rates ◽  
Moist Forest ◽  
Number Of Leaves

Abstract:We irrigated and fertilized (with nutrients) seedlings of Doliocarpus olivaceus (Dilleniaceae, a shade-tolerant liana), Faramea occidentalis (Rubiaceae, a shade-tolerant understorey tree) and Tetragastris panamensis (Burseraceae, a shade-tolerant canopy tree) growing in the understorey of an old-growth tropical moist forest in Panama to assess the impact of seasonal water availability and nutrient-poor soils on seedling growth rates. In control plots, height growth rates were greater in the dry season than in the wet season for Doliocarpus (21%) and for Faramea (89%), whereas Tetragastris had similar seasonal rates. For numbers of leaves, Faramea had 3.5-fold greater relative growth rates in the dry season than in the wet season, while Doliocarpus and Tetragastris lost leaves (semi-deciduous) during the same period. Irrigation and nutrient augmentation increased height growth rates for all three species (45% to 272%). For Doliocarpus, irrigation and nutrient augmentation prevented leaf fall during the dry season. For Faramea in the dry season, irrigation and nutrient augmentation when applied independently reduced the growth of new leaves by 65% to 87%, but relative growth rates for number of leaves were the same as the control rates in the combined irrigation and nutrient augmentation treatment. The growth of new leaves for Tetragastris responded to dry-season irrigation but not nutrient augmentation. Although all measurements occurred beneath the forest canopy, during the dry season, Tetragastris had a negative relationship between canopy openness and relative growth rate for number of leaves, whereas the other two species had a positive relationship. Our results show that soil resources influence growth rates even in the deep shade of the forest understorey, and demonstrate different responses to soil resources among species that might contribute to niche differentiation and species coexistence.

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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