Growth Analysis of Weed and Crop Species with Reference to Seed Weight

Weed Science ◽  
1993 ◽  
Vol 41 (1) ◽  
pp. 52-56 ◽  
Author(s):  
Andrew C. Seibert ◽  
R. Brent Pearce
Keyword(s):  
Growth Rates ◽  
Seed Weight ◽  
Growth Analysis ◽  
Plant Root ◽  
Morphological Characteristics ◽  
Initial Size ◽  
Crop Species ◽  
Relative Growth ◽  
Relative Growth Rates ◽  
Length Increase

Growth and morphological characteristics of four weed and two crop species were analyzed to determine how small-seeded weeds can compete with large-seeded crops despite the initial size disadvantage. Small-seeded weeds had higher relative growth rates because of increased percentages of biomass devoted to leaves. This morphological scheme was achieved primarily through a reduction in the percentage of biomass devoted to roots. Yet, small-seeded weeds were able to develop larger mean plant root lengths as a result of having both roots of smaller diameter and higher rates of root length increase.

Growth responses of six bryophyte species to different light intensities

1993 ◽  
Vol 71 (5) ◽  
pp. 661-665 ◽  
Author(s):  
Emmanuel Rincón
Keyword(s):  
Growth Rate ◽  
Light Intensity ◽  
Growth Rates ◽  
Growth Analysis ◽  
Total Chlorophyll ◽  
Light Conditions ◽  
Growth Responses ◽  
Relative Growth ◽  
Relative Growth Rates ◽  
Plastic Responses

The growth responses of Brachythecium rutabulum, Eurhynchium praelongum, Lophocolea bidentata, Plagiomnium undulatum, Pseudoscleropodium purum, and Thuidiurn tamariscinum, growing under seven different light conditions, were determined in a 36-day laboratory experiment. Biomass production, relative growth rate, chlorophyll content, and morphological plastic responses (bending of the shoots) were determined following initial and final harvests. All species achieved greater biomass as irradiance increased. This trend was also observed in the relative growth rates, which were higher as irradiance increased, for all the bryophytes investigated. All species except L. bidentata showed an increased elevation of the shoot as irradiance decreased. Total chlorophyll was higher in all species at the lowest irradiance level, but no clear differences were observed in the ratios of chlorophyll a to b for all the species. Key words: grassland bryophytes, light intensity, growth analysis, plasticity.

COMPARISON OF SEEDLING GROWTH OF ROUGH FESCUE AND TALL FESCUE

1969 ◽  
Vol 49 (4) ◽  
pp. 465-470
Author(s):  
D. B. Wilson ◽  
A. Johnston
Keyword(s):  
Tall Fescue ◽  
Growth Rates ◽  
Festuca Arundinacea ◽  
Growth Analysis ◽  
Dry Weight ◽  
Native Grass ◽  
Relative Growth ◽  
Relative Growth Rates ◽  
Net Assimilation ◽  
Rough Fescue

Seedlings of a native grass, rough fescue, Festuca scabrella Torr., and of a tame grass, tall fescue, Festuca arundinacea Schreb., were grown in the greenhouse for 10 weeks. Each week 20 plants of each species were destructively harvested for growth analysis. Leaf and tiller numbers and leaf lengths were recorded for an additional 10 plants of each species. Mean net assimilation rates of rough fescue were similar to those of tall fescue, but leaf area ratios were significantly lower. Thus, mean relative growth rates of rough fescue were less than those of tall fescue. Tiller numbers were similar for both species but rough fescue produced fewer leaves. Dry weight of tops of the tame grass produced during the 10-week period was about 17 times that produced by the native grass.

Growing Density and Container Volume Affect Nursery and Field Growth of Interior Spruce Seedlings

1991 ◽  
Vol 8 (4) ◽  
pp. 160-165 ◽  
Author(s):  
David G. Simpson
Keyword(s):  
Growth Rates ◽  
Initial Size ◽  
Planting Stock ◽  
Relative Growth ◽  
Relative Growth Rates ◽  
Field Growth ◽  
Interior Spruce ◽  
The Mean ◽  
Crop Biomass

Abstract Interior spruce (white or Englemann spruce) was grown in containers having volumes of 45 to 120 cm³ and at nursery densities of 64 to 1111 seedlings/m². In three experiments, seedlings grown at greater densities had decreased shoot and root weights, decreased stem diameters, and in some cases greater shoot heights. Seedlings grown in containers with greater volumes were larger. Interaction between container volume and growing density was such that the effect of container volume was only evident at growing densities less than 568 seedlings/m². Maximum crop biomass for interior spruce was found to be 3 kg/m². Crop uniformity decreased as maximum crop biomass was approached. The greatest number of uniformly larger (5 to 6 g) seedlings are produced at growing densities of 500 to 600 seedlings/m². Growth of outplanted seedlings suggested larger seedlings had greater field growth, but the mean relative growth rates (RGR) of different sized seedlings were not affected by nursery growing densities. The results reported support the view that larger planting stock has apparently greater growth not because of greater growth rates, but because of larger initial size and the compounding effect of growth. North. J. Appl. For. 8(4):160-165.

Shoot development in Betula papyrifera. IV. Comparisons between growth characteristics and expression of vegetative long and short shoots

1984 ◽  
Vol 62 (3) ◽  
pp. 446-453 ◽  
Author(s):  
J. Cartey Caesar ◽  
Alastair D. Macdonald
Keyword(s):  
Growth Rates ◽  
Stem Elongation ◽  
Morphological Characteristics ◽  
Axillary Buds ◽  
Betula Papyrifera ◽  
Short Shoot ◽  
Relative Growth ◽  
Relative Growth Rates ◽  
Long Shoots ◽  
Short Shoots

Postflush observations on shoots of Betula papyrifera Marsh. indicated that long and short shoots differ in a range of morphological characteristics. Long shoots developed from distal axillary buds and short shoots developed from proximal axillary buds on the previous year's long shoots. Consequently, the potential of a bud to develop into a long shoot decreased basipetally. Potential long-shoot buds had higher bud-relative growth rates, stem-relative growth rates, leaf-relative growth rates, and stem dry weights during the course of postflush growth. Changes in leaf thickness, expressed in terms of specific leaf area and specific leaf weight, indicated that long shoots temporarily had thinner leaves than did short shoots a few weeks after flushing. Net assimilate requirements in long shoots for late leaf and internodal expansion may explain these observations. Nearing maturity, long-shoot early leaves became thicker, possibly owing to greater shoot vigour and (or) higher photosynthetic efficiency. Consequently, mature long-shoot early leaves possessed larger and thicker laminae, longer petioles, more side nerve pairs, and tended to grow more in length than width than short-shoot leaves on shoots of comparable age. Leaves of older short shoots, 2–10 years old, attained a greater size and had longer petioles than those of 1-year-old short shoots. Stem elongation and the development and expression of leaves in long shoots seemed to have a correlative influence on the overall vigour of long shoots.

Effects of Carbon Dioxide Enrichment on the Growth and Morphology of Kudzu (Pueraria lobata)

Weed Science ◽  
1988 ◽  
Vol 36 (1) ◽  
pp. 28-36 ◽  
Author(s):  
Thomas W. Sasek ◽  
Boyd R. Strain
Keyword(s):  
Leaf Area ◽  
Growth Analysis ◽  
Morphological Characteristics ◽  
Pueraria Lobata ◽  
Stem Height ◽  
Relative Growth ◽  
Relative Growth Rates ◽  
Ecological Implications ◽  
Leaf Area Duration ◽  
Net Assimilation

Kudzu (Pueraria lobataOhwi # PUELO) was grown from seeds in controlled-environment chambers at 350, 675, or 1000μl·1−1CO2. Biomass and leaf area production, morphological characteristics, and growth analysis components were determined at 14, 24, 45, and 60 days after emergence. At 60 days, plants grown at 1000μl·1−1CO2had 51% more biomass, 58% longer stems, and 50% more branches than plants grown at 350μl·1−1CO2. Plants grown at 675μl·1−1CO2were intermediate. Growth analysis components indicated that CO2enrichment increased growth by compounding effects due to increased net assimilation rates and increased leaf area duration. Relative growth rates were not significantly affected. The large CO2-induced increase in stem height versus stem diameter is in marked contrast to previously reported responses of woody erect growth forms. Possible ecological implications for competitive abilities are discussed.

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.

Sign in / Sign up

Export Citation Format

Share Document