Relative Growth of Themeda Australis and Poa Labillardieri in Pots in Response to Phosphorus and Nitrogen.

1973 ◽  
Vol 21 (1) ◽  
pp. 1 ◽  
Author(s):  
RH Groves ◽  
K Keraitis ◽  
cWE Moore ◽  
HJ Langer
Keyword(s):  
Shoot Growth ◽  
New South ◽  
Statistical Treatment ◽  
Dry Weight ◽  
Competitive Effect ◽  
Relative Growth ◽  
Shoot Dry Weight ◽  
South Wales ◽  
Shoot Weight ◽  
Nitrogen Contents

Results are presented of a pot experiment on the responses of Themeda australis and Poa labillardieri to increasing levels of substrate phosphorus and nitrogen. The species were grown either alone or together. When grown alone both species responded to increasing phosphorus and nitrogen and there was a significant interaction between the two elements in shoot growth per half-pot. There was no effect of increasing phosphorus without added nitrogen and no effect of increasing nitrogen without added phosphorus. At intermediate and high levels of substrate phosphorus there was a significant competitive effect between the shoot weight per half-pot and the tiller number of Themeda and Poa plants when grown together, irrespective of the nitrogen level. Poa always had a greater shoot dry weight and more tillers when grown with Themeda than when grown alone, and conversely Themeda a lower shoot dry weight and less tillers when grown with Poa than when grown alone. Chemical analyses of 22-week-old plant tissue showed that in Poa plants grown with Themeda the phosphorus and nitrogen contents were significantly greater than in Poa plants grown alone, at both intermediate and high levels of substrate phosphorus. The enhanced ability of Poa plants to absorb nutrients and grow in response to a low level of added phosphorus at the expense of Themeda plants when the two species are mixed in pots is similar to their response in the field in southern New South Wales. A description of the statistical treatment of the results, especially the competitive effect between Themeda and Poa when grown together, is appended.

scholarly journals Shading and DCPTA Interactively Influence Shoot Growth of Hypoestes

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 854D-854
Author(s):  
Sven E. Svenson
Keyword(s):  
Shoot Growth ◽  
Seedling Emergence ◽  
Tween 80 ◽  
Dry Weight ◽  
Distilled Water ◽  
Seedling Height ◽  
Shoot Dry Weight ◽  
Randomized Design ◽  
Completely Randomized Design ◽  
Shoot Weight

The objective of this study was to determine if shading and DCPTA application interactively influence seedling emergence and shoot growth of Hypoestes phyllostachya Bak. seedlings. Hypoestes `Carmine Red' seeds were soaked for 6 h in distilled water, and then soaked 6 h in solutions containing' 10 mg DCPTA/liter (30 mM) and 0.1% Tween-80, 0.1% Tween-80, or distilled water. Date of seedling emergence was recorded after sowing (0.5 cm) in 9-cm (460 ml) pots filled with 440 ml of a 5 pine bark: 4 Florida sedge peat: 1 sand medium. Forty pots from each of the three seed-soak treatments were grown under 30%, 63%, or 84% shading, provided by saran-type shadecloth, using natural photoperiods (completely randomized design). Shoot heights and dry weights were recorded 75 days after sowing. Neither shading nor DCPTA influenced total seedling emergence or seedling emergence rate (time to 50% emergence). Under 30% shading, seedlings from DCPTA-treated seeds were taller and had more shoot dry weight than seedlings from surfactant- or water-treated-seeds; however, DCPTA did not influence seedling height or shoot weight under 63% or 84% shading.

Reduced early growth of direct drilled wheat in southern New South Wales: causes and consequences

1987 ◽  
Vol 27 (6) ◽  
pp. 869 ◽  
Author(s):  
PS Cornish ◽  
JR Lymbery
Keyword(s):  
Water Use ◽  
Shoot Growth ◽  
New South ◽  
New South Wales ◽  
Dry Weight ◽  
Early Growth ◽  
Plant Population ◽  
Root Extension ◽  
South Wales ◽  
Direct Drilling

In five experiments with wheat over 4 years on a red earth soil in southern New South Wales, direct drilling reduced plant population by an average of 15% and individual plant dry weight at 10- 11 weeks by an average maximum of 33% compared with sowing into a cultivated seed bed. The maximum reduction in dry weight per unit area averaged 44% (at tillering), but compensatory growth reduced this to 17% by anthesis. Time to emergence was not reduced and differences in plant weight soon after emergence were very small, which suggests that the effect on plant growth occurred only after emergence. Effects of direct drilling on soil surface (0- 10 cm) temperature and water content were not important factors reducing plant population or early growth but high soil strength seemed the most likely cause of reduced root extension in the direct drilled seedbed (0-1 5 cm). Reduced root extension had no direct effect on plant water relations or nitrogen concentration in leaves, but there was a small effect on phosphorus concentration. Reduced root growth appears to reduce shoot growth but the mechanisms require further study. The reduced shoot growth led to reduced preanthesis water-use. After anthesis direct drilled crops generally used more water and had higher leaf water potentials than crops in cultivated soil, leading to yield increases in 2 of the years with dry spring conditions. Only in a drought year (1982) was there evidence of direct drilling reducing the maximum depth of rooting and therefore reducing total water-use resulting in lower grain yield (8%). Overall, direct drilling increased grain yields by 2.4% (2.514 v. 2.576 t/ha) compared with conventional tillage, despite the large reduction in early growth.

scholarly journals Effect of Repeated Short Interval Flooding Events on Root and Shoot Growth of Four Landscape Shrub Taxa

2011 ◽  
Vol 29 (4) ◽  
pp. 220-222
Author(s):  
Kathryne J. Jernigan ◽  
Amy N. Wright
Keyword(s):  
Shoot Growth ◽  
No Reduction ◽  
Southeastern United States ◽  
Short Interval ◽  
Dry Weight ◽  
Shoot Dry Weight ◽  
Flooding Event ◽  
Root And Shoot Growth ◽  
Size Index ◽  
Flooding Events

Abstract Research was conducted to screen four landscape shrub taxa for tolerance to repeated flooding events. Plants of Fothergilla × intermedia ‘Mt. Airy’ (dwarf witchalder), Ilex verticillata ‘Winter Red’ (winterberry), Clethra alnifolia ‘Ruby Spice’ (summersweet), and Viburnum nudum Brandywine™ (possumhaw) were flooded repeatedly over six weeks for 0 (non-flooded), 3, or 6 days with a draining period of 6 days between each flooding event. The experiment was repeated for a total of two runs. With the exception of F. × intermedia ‘Mt. Airy’, all taxa showed good visual quality and no reduction in root growth in either run, and effects on shoot growth were minimal. Size index of Clethra alnifolia ‘Ruby Spice’ was 27% higher in plants flooded for 0 or 3 days than in plants flooded for 6 days in run 1 only. Shoot dry weight of Ilex verticillata ‘Winter Red’ was actually 11% higher in plants flooded 6 days days than in plants flooded for 0 or 3 days in run 2. Size index of Viburnum nudum Brandywine™ increased with increasing flood length, and plants flooded for 6 days had a 9% higher SI than plants flooded for 0 days in run 1. With the exception of Fothergilla × intermedia L. ‘Mt. Airy’, all taxa appeared tolerant of and even thrived during flooding and would be appropriate shrub selections for a southeastern United States rain garden.

scholarly journals Emergence and Shoot Growth of Cosmos and Marigold from Paclobutrazol-treated Seed

2001 ◽  
Vol 19 (1) ◽  
pp. 11-14 ◽  
Author(s):  
Wallace G. Pill ◽  
James A. Gunter
Keyword(s):  
Growth Medium ◽  
Shoot Growth ◽  
Dry Weight ◽  
Tagetes Patula ◽  
Shoot Height ◽  
Shoot Dry Weight ◽  
Grade 5 ◽  
Treated Seed ◽  
Emergence Percentage ◽  
And Control

Abstract This study was conducted to determine whether treating seeds of ‘Sensation Mixed’ cosmos (Cosmos bipinnatus Cav.) and ‘Bonanza Gold’ marigold (Tagetes patula L.) with paclobutrazol (PB) could suppress seedling growth. Seeds were soaked in solutions of 0, 500 or 1000 mg PB/liter (ppm PB) for 16 hours at 25C (77F) or they were primed [−0.5 MPa (−5 bars) for 7 days at 20C (68F)] in Grade 5 exfoliated vermiculite moistened with 0, 500 or 1000 ppm PB solltuions. Soaked and primed seeds were dried for 1 day at 19C (65F) and 25% relative humidity. These seeds and control (non-treated) seeds were sown into plug cells containing peat-lite. Increasing PB concentration decreased cosmos shoot height at 32 days after planting (DAP), but decreased emergence percentage, responses that were more pronounced with priming than with soaking. A 1 ppm PB growth medium drench [30 ml/cell(0.2 mg PB/cell)] and, to a greater extent a 10 mg PB/liter (ppm PB) shoot spray [2 ml/shoot (0.02 mg PB/shoot)], both applied at 10 DAP, resulted in greater cosmos shoot height suppression at 32 DAP than treatment of seeds with 1000 ppm PB. Soaking marigold seeds in 1000 ppm PB failed to decrease shoot height below those of plants from non-treated seeds at 32 DAP. However, exposure to 1000 ppm PB during priming of marigold seeds resulted in a similar shoot height suppression (13%) as the growth medium drench, and similar shoot dry weight reduction (21%) as the shoot spray. Suppression of shoot growth by this seed treatment was short-term since by five weeks after transplanting into 15 cm (6 in) pots, only marigold plants that had received the growth medium drench or shoot spray were smaller than those of control plants. Treating marigold seeds with 1000 mg ppm PB used about one-fifth the PB used to drench the growth medium.

scholarly journals Evaluation of a Substrate-applied Humectant to Mitigate Drought Stress in Young, Container-grown Plants

2015 ◽  
Vol 33 (3) ◽  
pp. 137-141
Author(s):  
Bruce R. Roberts ◽  
Chris Wolverton ◽  
Samantha West
Keyword(s):  
Drought Stress ◽  
Root Growth ◽  
Shoot Growth ◽  
Dry Weight ◽  
Root:Shoot Ratio ◽  
Xylem Water Potential ◽  
Bedding Plants ◽  
Shoot Dry Weight ◽  
Soilless Substrate ◽  
Absorbing Roots

The efficacy of treating soilless substrate with a commercial humectant was tested as a means of suppressing drought stress in 4-week-old container-grown Zinnia elegans Jacq. ‘Thumbelina’. The humectant was applied as a substrate amendment at concentrations of 0.0, 0.8, 1.6 and 3.2% by volume prior to withholding irrigation. An untreated, well-watered control was also included. The substrate of treated plants was allowed to dry until the foliage wilted, at which time the plants were harvested and the following measurements taken: number of days to wilt (DTW), xylem water potential (ψx), shoot growth (shoot dry weight, leaf area) and root growth (length, diameter, surface area, volume, dry weight). For drought-stressed plants grown in humectant-treated substrate at concentrations of 1.6 and 3.2%, DTW increased 25 and 33%, respectively. A linear decrease in ψx was observed as the concentration of humectant increased from 0.0 to 3.2%. Linear trends were also noted for both volumetric moisture content (positive) and evapotranspiration (negative) as the concentration of humectant increased. For non-irrigated, untreated plants, stress inhibited shoot growth more than root growth, resulting in a lower root:shoot ratio. For non-irrigated, humectant-treated plants, the length of fine, water-absorbing roots increased linearly as humectant concentration increased from 0.0 to 3.2%. Using humectant-amended substrates may be a management option for mitigating the symptoms of drought stress during the production of container-grown bedding plants such as Z. elegans.

scholarly journals Seedling Developmental Stage at Transplanting Affects Growth and Flowering of Medallion Flower and Globe Amaranth

2015 ◽  
Vol 33 (2) ◽  
pp. 53-57 ◽  
Author(s):  
G.J. Keever ◽  
J.R. Kessler ◽  
G.B. Fain ◽  
D.C. Mitchell
Keyword(s):  
Shoot Growth ◽  
Growth Index ◽  
Dry Weight ◽  
Development Stage ◽  
Seedling Development ◽  
Bedding Plants ◽  
Shoot Dry Weight ◽  
Flower Growth ◽  
Root Restriction ◽  
Experimental Runs

A study was conducted to determine how seedling development stage at transplanting from plug flats into small pots affected growth and flowering of two commonly grown bedding plants. Seeds of Showstar® medallion flower and ‘Las Vegas Pink’ globe amaranth were sown in 392-cell flats on five dates for each of two experimental runs before transplanting into 8.9 cm (3.5 in) cubic pots. At transplanting of both species, plant height, node count and shoot dry weight increased as days from sowing to transplanting increased and there was no visible cessation in shoot growth due to root restriction. Time to first flower from transplanting decreased linearly with both species in both runs, except with medallion flower in the second run, as time from sowing to transplanting increased. In contrast, time to flower of both species from sowing increased linearly as time from sowing to transplanting increased. However, the magnitude of the increase or decrease in time to flower differed between the two runs indicating that other factors, most likely light intensity and duration, besides node counts were affecting time to flower. Globe amaranth height and growth index and medallion flower growth index at first flower decreased as time from sowing to transplanting increased, whereas medallion flower height was not affected by time from sowing to transplanting.

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.

Diet and growth of rainbow trout, Salmo gairdneri Richardson, in two streams on the New England Tableland, New South Wales

1981 ◽  
Vol 32 (6) ◽  
pp. 967 ◽  
Author(s):  
RWJ Pidgeon
Keyword(s):  
Rainbow Trout ◽  
New England ◽  
New South ◽  
New South Wales ◽  
Rank Correlation ◽  
Dry Weight ◽  
Fish Growth ◽  
Salmo Gairdneri ◽  
Fish Size ◽  
South Wales

The diets and growth rates of rainbow trout in the Wollomombi and Guy Fawkes Rivers in northern New South Wales were examined. The growth rate of trout in the Wollomombi River was much higher than that of fish in the Guy Fawkes River. Spearman rank correlation coefficients indicated that stream type was more important than fish size in determining the composition of the diet of the trout. Benthic invertebrates formed the largest component of the diet in both streams: 66.0 and 63.0% of ash-free dry weight (AFDW) in the Wollomombi River and the Guy Fawkes River, respectively. Trout in the Wollomombi River consumed more nektonic prey (33.3% of AFDW) than fish in the Guy Fawkes River (3.7% of AFDW). In contrast, surface food (aquatic imagines and terrestrial insects) made up a much higher proportion of the diet of trout in the Guy Fawkes River (33.9% of AFDW) than in the Wollomombi River (0.6% of AFDW). Crayfish were a major component of the diet (in terms of AFDW) in both streams, their proportions increasing with fish size. The significance of crayfish in relation to fish growth is discussed.

Australian canola germplasm differs in nitrogen and sulfur efficiency

2008 ◽  
Vol 59 (2) ◽  
pp. 167 ◽  
Author(s):  
Tatjana Balint ◽  
Zdenko Rengel ◽  
David Allen
Keyword(s):  
Genotypic Variation ◽  
Dry Weight ◽  
Breeding Programs ◽  
Relative Growth ◽  
Breeding Lines ◽  
Shoot Dry Weight ◽  
Sulfur Supply ◽  
Utilisation Efficiency ◽  
Low Sulfur ◽  
Low Nitrogen

Eighty-four canola genotypes, including current commercial Australian genotypes, some older Australian genotypes, new breeding lines, and several genotypes from China, were screened for nitrogen and sulfur efficiency in the early growth stage. Plants were grown in a glasshouse using virgin brown Lancelin soil (Uc4.22) supplied with basal nutrients. The treatments were: (i) adequate nitrogen and sulfur, (ii) low nitrogen, and (iii) low sulfur. Canola shoots were harvested at 38 days after sowing when growth reduction and the nitrogen and sulfur deficiency symptoms were evident in most genotypes. The nitrogen or sulfur efficiency in canola genotypes was evaluated on the basis of: (1) growth at low nitrogen or sulfur supply, (2) growth at low relative to adequate nitrogen and sulfur supply, and (3) nitrogen or sulfur utilisation efficiency expressed as shoot dry weight per unit of nitrogen or sulfur content in shoots. Genotypic variation in growth and nitrogen or sulfur efficiency in canola germplasm was significant. Two genotypes (Chikuzen and 46C74) were ranked efficient and 2 inefficient (CBWA-005 and Beacon) in uptake and utilisation of nitrogen under all 3 criteria. In terms of sulfur efficiency, genotype Argentina was ranked efficient, whereas CBWA-003 and IB 1363 were classified inefficient under all 3 criteria. Two canola genotypes (Surpass 600 and 46C74) were both nitrogen- and sulfur-efficient in terms of relative growth at low v. adequate nutrition; their use in the breeding programs could be considered.

scholarly journals Cutless Controls Shoot Growth of ‘China Girl’ Holly

1994 ◽  
Vol 12 (3) ◽  
pp. 167-169
Author(s):  
G.J. Keever ◽  
C.H. Gilliam ◽  
D.J. Eakes
Keyword(s):  
Growth Inhibition ◽  
Shoot Growth ◽  
Growth Index ◽  
Dry Weight ◽  
Shoot Length ◽  
Single Application ◽  
Growing Seasons ◽  
Shoot Dry Weight ◽  
Production Growth ◽  
Container Production

Abstract Ilex x meserveae ‘China Girl’ plants were sprayed with a single application of different rates of Cutless (flurprimidol) during container production. Growth index, shoot length and shoot dry weight decreased with increasing rates of Cutless. Growth index of plants treated with 500 ppm Cutless was about 17% less than that of control plants 120 days after treatment, but were similar after the spring flush the following year. Growth inhibition persisted for at least two growing seasons when plants were treated with rates of 1500 to 2500 ppm; foliage of these plants was smaller and more cupped than that of control plants. Treated plants were noticeably more compact and uniform, and foliage was darker green than that of control plants.

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