Aphid-induced changes in growth indices of three leguminous plants: unrestricted infestation

1985 ◽  
Vol 63 (12) ◽  
pp. 2454-2459 ◽  
Author(s):  
C. D. B. Hawkins ◽  
M. J. Aston ◽  
M. I. Whitecross
Keyword(s):  
Acyrthosiphon Pisum ◽  
Growth Patterns ◽  
Relative Growth ◽  
Relative Growth Rates ◽  
Unit Leaf ◽  
Aphis Craccivora Koch ◽  
The Mean ◽  
Net Assimilation ◽  
Induced Changes ◽  
And Control

The effects of various densities of cowpea aphids (Aphis craccivora Koch) and pea aphids (Acyrthosiphon pisum Harris), both Homoptera: Aphididae, on the growth of cowpea (Vigna unguiculata (L.) Walp. cv. Caloona), broad bean (Vicia faba L. cv. Aquadulce), and garden pea (Pisum sativum L. cv. Victory Freezer) seedlings were investigated. Within 10 days of infestation, aphid feeding significantly reduced plant dry weights and mean relative growth rates for the six plant–aphid combinations. In all cases except one, the mean unit leaf or net assimilation rate was also significantly reduced within 10 days. The mean leaf area ratio was the same for infested and control plants. The aphid-induced changes in host plants appear to be due to changes in photosynthesis, respiration, and translocate removal from the phloem over the 10-day period. Changes in the growth patterns of the host plant within this period are similar, but the underlying physiological effects could vary among particular plant–aphid combinations.

scholarly journals Early Growth of Muskmelon in Mulched Minitunnels Containing a Thermal Water Tube. II. Air, Soil, and Water Tube Temperatures and Vegetative Growth

2001 ◽  
Vol 126 (6) ◽  
pp. 764-770 ◽  
Author(s):  
Fahrurrozi Aziz ◽  
Katrine A. Stewart ◽  
Sylvie Jenni
Keyword(s):  
Vegetative Growth ◽  
Cucumis Melo ◽  
Thermal Water ◽  
Field Experiments ◽  
Relative Growth ◽  
Relative Growth Rates ◽  
Water Tube ◽  
Net Assimilation ◽  
And Control ◽  
Soil And Water

Field experiments were conducted during 1997, 1998, and 1999 to determine effects of 10 combinations of mulched minitunnel and thermal water tube on air, soil, and water-tube temperatures and on vegetative growth of `Earligold' netted muskmelon (Cucumis melo L. Reticulatus Group) within the tunnels. Use of mulched minitunnels significantly increased air, soil and water temperatures during the preanthesis phase in all years compared with control treatments. Inclusion of water tubes and venting the tunnels decreased air temperature fluctuations in the tunnels. During the first 10 to 15 days after transplanting, plants grown in nonperforated tunnels had higher relative growth rates (RGRs), net assimilation rates (NARs), and dry weights (DWs) than those grown under perforated tunnels and control plots. Plants in tunnels containing thermal water tubes generally had higher RGRs, NARs, and DWs than those without tubes. During the later part of the experiment, from 11 to 16 days after transplanting until anthesis, however, there were no consistent effects of mulched minitunnels on RGR, NAR, and plant DW. Tunneled muskmelons had significantly higher RGRs, but generally lower NARs than those grown without tunnel. Use of mulched minitunnels significantly increased plant DW at anthesis in 1997, but not in 1998 and 1999. Plants grown in the minitunnels containing a thermal water tube generally had higher RGRs, NARs, and DWs than those without water tubes. Ventilating nonperforated tunnels generally increased RGR, NAR, and plant DW. Plants grown in the tunnels reached anthesis 10 days earlier than those without tunnels.

Long-term effects on cowpea plant growth of a short-term cowpea aphid infestation

1986 ◽  
Vol 64 (8) ◽  
pp. 1727-1732 ◽  
Author(s):  
C. D. B. Hawkins ◽  
M. I. Whitecross ◽  
M. J. Aston
Keyword(s):  
Compensatory Growth ◽  
Detectable Effect ◽  
Long Term Effects ◽  
Aphid Infestation ◽  
Relative Growth Rates ◽  
Unit Leaf ◽  
Aphis Craccivora Koch ◽  
Experimental Treatments ◽  
Induced Changes

Two-week-old cowpea seedlings (Vigna unguiculata (L.) Walp.) were infested with cowpea aphids (Aphis craccivora Koch (Homoptera: Aphididae)) for 5, 10, 15, and 20 days at which time the aphids were removed with a systemic insecticide. The seedlings were then allowed to grow for another 3 months. By day 10, plant dry weights, mean relative growth rates [Formula: see text], and mean unit leaf rates (Ē) were all significantly reduced in the infested plants, and these relationships still held at day 20. Apparent decreases in photosynthesis and (or) increases in respiration were the primary causes of these reductions. There were no significant differences between control and experimental treatments for [Formula: see text] calculated from day 0, and total number of seeds and seed pods produced at the end of the study. Control plants had significantly more mature seed pods and seeds, while formerly infested plants had significantly more mature and unripe seeds per pod, more unripe seed pods and seeds produced, and greater values for [Formula: see text] from the time of aphid removal until the end of the experiment. This latter increase in [Formula: see text] indicates a form of compensatory growth. It is proposed that the compensatory growth of previously infested plants and ultimate similarity in seed production, as compared with control plants, may have resulted from aphid-induced changes via nonhormonal compounds acting as phytohormone regulators. The different durations of aphid infestation used had no detectable effect on long-term growth.

scholarly journals Response of growth patterns in sweet pepper to different NPK levels

2008 ◽  
Vol 56 (1) ◽  
pp. 241-244 ◽  
Author(s):  
Mohamed Ewis Abdelaziz ◽  
A. H. Hannfy Ahmed ◽  
R. S. Bekhid ◽  
Robert Pokluda
Keyword(s):  
Growth Rate ◽  
Leaf Area ◽  
Growth Analysis ◽  
Sweet Pepper ◽  
Area Ratio ◽  
Growth Patterns ◽  
Relative Growth ◽  
Mean Values ◽  
The Mean ◽  
Net Assimilation

This work was conducted to study the effect of five NPK fertigation levels on the growth rate of sweet pepper (Capsicum annuum L. cv. Bruyo) grown under the plastic greenhouse using different growth analysis formulas. Leaf area ratio (LAR), specific leaf area (SLA), relative growth rate (RGR) and net assimilation rate (NAR) was evaluated in two periods (60–90 and 90–120 days after transplanting). The mean values of LAR, SLA, RGR and NAR tended to decrease significantly with advancing plant age in both seasons. In general, at the moderate level (34N-42P-29K / plastic house 540 m2) was found the highest significant values of LAR and SLA in the two growth periods. On the other hand, the highest values of NAR were recorded at the plants treated with the lowest NPK fertigation level (17N-21P-15K / plastic house 540 m2). However, increase of NPK fertigation doses to the moderate levels had favorable effects on LAR and SLA of sweet pepper plants.

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.

Studies on the productivity of tropical pasture plants. V.* Effect of shading on growth, photosynthesis and respiration in two grasses and two legumes

1974 ◽  
Vol 25 (3) ◽  
pp. 425 ◽  
Author(s):  
MM Ludlow ◽  
GL Wilson ◽  
MR Heslehurst
Keyword(s):  
Radiant Energy ◽  
Net Assimilation Rate ◽  
Assimilation Rate ◽  
Pasture Production ◽  
Relative Growth ◽  
Relative Growth Rates ◽  
Analysis Techniques ◽  
Net Assimilation ◽  
Photosynthesis And Respiration ◽  
Pasture Plants

Two grasses and two legumes were grown at three illuminances: one grass and one legume in a growth cabinet (100, 50 and 34% relative illuminance) and one of each in a glasshouse (100, 30 and 10% relative illuminance). The response to shading was investigated by using classical growth analysis techniques, and the photosynthesis-respiration balance obtained by Watson and Hayashi's method. Shading caused a reduction in the proportion of root and a corresponding increase in the proportion of leaf, and an increase in the shoot/root ratio in all species except green panic. The relative growth rates of grasses (which were only clearly superior at the highest illuminance) were affected more by shading than were those of legumes, and the greater shading effect resulted from a greater decrease in net assimilation rate, and to a lesser extent, from a smaller compensatory increase in leaf area ratio in the grasses than in the legumes. The greater sensitivity of net assimilation rate of grasses to shading arose from a stronger dependence of the photosynthetic rate on illuminance. The significance of these findings for pasture production is discussed. Both tiller and runner production were dependent upon the total amount of radiant energy received by the plant, and in the growth cabinet, at least, were independent of its intensity, duration and sequence. ______________________ *Part IV, Aust. J. Agric. Res., 25: 415 (1974).

Invasion by Pittosporum undulatum of the Forests of Central Victoria. III. Effects of Temperature and Light on Growth and Drought Resistance

1982 ◽  
Vol 30 (3) ◽  
pp. 347 ◽  
Author(s):  
RM Gleadow ◽  
KS Rowan
Keyword(s):  
Leaf Area ◽  
Photon Flux ◽  
First Year ◽  
Low Light ◽  
Relative Growth ◽  
Relative Growth Rates ◽  
Drought Tolerant ◽  
Deep Shade ◽  
Net Assimilation ◽  
Shade Plants

The clumping of invading seedlings of Pittosporum undulatum Vent. around the butts of established trees is due partly to the site-dependent survival of seedlings. particularly during summer. P. undulatum seedlings were very drought-tolerant when grown at moderately low temperatures (21.4°C day/17.8°C night compared with 27.4°C day/23.9°C night) and in deep shade. Plants droughted at 5°C higher temperatures and higher photon flux densities stopped transpiring and wilted 10-13 days earlier than those droughted under cooler, densely shaded conditions. Well watered seedlings had higher relative growth rates and net assimilation rates when grown under higher temperatures and photon flux densities. Control seedlings were more leafy when grown under low light. as reflected by the specific leaf area, leaf area ratio and root/shoot ratios. The adverse effects of higher photon flux densities and temperatures on the drought tolerance of P. undulatum seedlings support the hypothesis that survlval of invading seedlings in their first year is dependent on the microclimate.

Androgen Stimulation and Laryngeal Development

1985 ◽  
Vol 94 (6) ◽  
pp. 634-640 ◽  
Author(s):  
Neal S. Beckford ◽  
Dan Schaid ◽  
Stewart R. Rood ◽  
Bruce Schanbacher
Keyword(s):  
Animal Model ◽  
Thyroid Cartilage ◽  
Inhibitory Effect ◽  
Growth Patterns ◽  
Treatment Groups ◽  
Vocal Process ◽  
Angular Measurements ◽  
The Mean ◽  
Induced Changes ◽  
Anterior Posterior

Androgen-induced changes in laryngeal growth patterns were studied using a sheep animal model. Forty-eight lambs were divided into eight treatment groups. Lambs in seven of the groups were castrated at birth, while lambs in the eighth group served as an intact (non-castrated) control. Six groups were then treated with varying doses of testosterone and dihydrotestosterone, while the seventh served as a castrated, nontreated control. All animals were killed and gross dissections of the larynges were performed. Thirty-four linear and angular measurements were obtained from each larynx. The mean superior thyroid horn separation showed the most dramatic androgen-induced effect (p = 0.023). Laryngeal anterior-posterior diameter, superior thyroid horn height, posterior thyroid cartilage width, thyroid cartilage angle, and vocal process to arytenoid base distances all demonstrated positive dose-response relationships. Hypoandrogenic levels appeared to have an inhibitory effect upon laryngeal growth when compared to castrated controls.

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.

Comparative breed studies of beef cattle. I. Changes in body weight

1963 ◽  
Vol 14 (6) ◽  
pp. 882 ◽  
Author(s):  
NM Tulloh
Keyword(s):  
Body Weight ◽  
Growth Rates ◽  
The Other ◽  
Relative Growth ◽  
Relative Growth Rates ◽  
Breed Differences ◽  
Weaning Age ◽  
Absolute Growth ◽  
The Mean ◽  
One Year

A comparative growth study was made of Hereford, Aberdeen Angus, and beef Shorthorn cattle reared and kept together throughout their lives on irrigated perennial pastures at the Metropolitan Farm, Werribee, Vic. Records of body weight as a function of age were obtained on 404 Hereford, 172 Aberdeen Angus, and 127 Shorthorn cattle, representing cattle born in 1955, 1957, 1958, 1959, and 1960. At birth, male calves were significantly heavier than females, and Hereford calves were significantly heavier than Shorthorn and Aberdeen Angus calves, the birth weights of Shorthorn and Aberdeen Angus calves being similar. Up to the age of 5 years, the younger and lighter 2-year-old cows produced lighter calves than cows which were both older and heavier. At weaning age (9.5 months) steers were significantly heavier than heifers. Herefords were significantly heavier than Aberdeen Angus in two years out of three; and in one year out of three, Herefords were significantly heavier than Shorthorns. Shorthorns were significantly heavier than Aberdeen Angus in one year out of three. When the steers were finally weighed off grass at the mean age of either 20 months (1958, 1959, and 1960 cattle) or 25 months (1957 cattle), Herefords were significantly heavier than Aberdeen Angus in four successive years, and in one year out of four the Herefords were significantly heavier than Shorthorns. In three years out of four, Shorthorns were significantly heavier than Aberdeen Angus. Breed differences between the mean weights of breeding cows were not significant and, up to the age of 5 years, as breeding cows grew older they became heavier. Body weight growth curves indicated that the cattle experienced a severe check in growth during the winter months (June, July, August). At other times of the year, growth rates were satisfactory. Cattle born in some years grew better than cattle born in others. This was thought to be due partly to differences between years in the quality and quantity of pasture available, even though the pastures were irrigated. Average absolute and average relative growth rates were calculated for the 1957 and 1958 steers before and after weaning. Breed differences in absolute growth rates before weaning were not statistically significant, but after weaning, rates were significantly the highest for Herefords in both years. The breed differences in average relative growth rates were in the same direction as those for absolute growth rates. However, the pre-weaning relative growth rate of Shorthorns was significantly higher than those of the other breeds among the 1957 steers. When due allowance was made for the smaller size of Aberdeen Angus steers at birth and at weaning, the relative growth rates of this breed were less than those of the other breeds. Absolute and relative growth rates were higher for all breeds before weaning than afterwards. This was mainly a reflexion of low post-weaning growth rates during the winter months. Rank correlation coefficients between birth weight and weight at subsequent ages were low and variable in different breeds and in different seasons. However, coefficients calculated between subsequent ages, beginning at weaning age, were generally highly significant. The breed and sex differences presented in this paper have been compared with the limited data from the literature and, in general, the results are similar.

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