scholarly journals Testing a New Approach to Quantify Growth Responses to Pruning Among Three Temperate Tree Species

2016 ◽  
Vol 42 (3) ◽  
Author(s):  
Matt Follett ◽  
Charles Nock ◽  
Christian Buteau ◽  
Christian Messier
Keyword(s):  
Growth Rate ◽  
Growth Response ◽  
Abiotic Factors ◽  
Growth Conditions ◽  
Accurate Estimation ◽  
Cycle Duration ◽  
Growth Responses ◽  
Laser Measurements ◽  
Branch Growth ◽  
Highly Correlated

In settled areas, electrical line safety is maintained by pruning encroaching trees. Identifying key predictors of branch elongation growth rate following pruning would assist in developing predictive models and optimizing pruning cycles. However, measuring branches in trees near electrical lines is complex and challenging. This paper describes an innovative approach using a handheld laser rangefinder to safely and accurately estimate growth from the ground. In-tree and ground-based laser measurements were highly correlated. This was followed by testing for correlations between branch growth response over a number of years after pruning and many biotic and abiotic factors for Fraxinus pennsylvanica, Acer platanoides, and Acer saccharinum, in the city of Montreal, Canada. In a sample of 59 trees, A. saccharinum had the greatest branch growth, followed by F. pennsylvanica, and finally A. platanoides. Branch growth increased following pruning and subsequently strongly declined, with A. platanoides declining the fastest. Branch inclination angle was positively correlated with growth rate for two species, but not for A. saccharinum. Among the types of pruning used, directional pruning techniques resulted in the least branch regrowth rate. Tree diameter was weakly related to branch growth rates. These results suggest that while growth conditions for street trees may be perceived as homogenous, there is substantial variation in branch growth response. This variation may be related to pruning history, or unmeasured abiotic or biotic variables. Estimating pruning cycle duration is a complex task and further work is needed to develop a predictive model for more accurate estimation of return times.

scholarly journals GROWTH SUBSTANCE CURVATURES OF AVENA IN LIGHT AND DARK

1936 ◽  
Vol 20 (2) ◽  
pp. 283-309 ◽  
Author(s):  
J. Van Overbeek
Keyword(s):  
Growth Hormone ◽  
Growth Rate ◽  
Growth Response ◽  
Growth Substance ◽  
Continuous Exposure ◽  
Growth Responses ◽  
Section 8 ◽  
Oxidative Inactivation

An attempt has been made to analyze the base response, one of the light growth responses of Avena coleoptiles, by means of growth substance curvatures. The decrease in growth rate (first part of the base response) after exposure to light does not show if hetero-auxin is substituted for auxin-a (Sections 5, 6, and 10). This decreased growth after exposure very likely is due to an oxidative inactivation of auxin-a (Sections 8 and 9). Hetero-auxin can be inactivated too but in a much lesser degree than auxin-a (Section 9). The increase in growth rate following on the decreased growth (second part of the base response) is due to an increase in response of the plant to growth hormone which is independent of the type of hormone (Sections 1, 2, 7, 8, and 10). Under conditions of continuous exposure to light, however, the inactivation of the auxin-a under influence of the light is superimposed on this increased response to growth hormone. This inactivation can be eliminated from the light growth response by replacing the auxin-a by hetero-auxin. More detailed information on this subject can be found in Section 10. A review of the experiments and their results can be obtained from the scheme in Section 8. In Section 11 it is shown that light inhibits the formation of growth hormone in the decapitated coleoptile (regeneration). Very small amounts of light (25 m.c.s.) inhibit the regeneration markedly.

scholarly journals ADDITION OF SHELTERS TO CONTROL THE PHYSIOLOGICAL RESPONSES AND PRODUCTION OF MUD CRAB Scylla serrata IN RECIRCULATION AQUACULTURE SYSTEM

2020 ◽  
Vol 12 (1) ◽  
pp. 299-310
Author(s):  
Yuni Puji Hastuti ◽  
Priyo Handoyo Wicaksono ◽  
Wildan Nurusallam ◽  
Siska Tridesianti ◽  
Yuli Siti Fatma ◽  
...  
Keyword(s):  
Growth Rate ◽  
Abiotic Factors ◽  
Physiological Responses ◽  
Scylla Serrata ◽  
Growth Responses ◽  
Aquaculture System ◽  
Total Hemocyte Count ◽  
Recirculation System ◽  
Recirculation Aquaculture System ◽  
Mud Crabs

The availability of shelters in a specific density is expected to increase the production of mud crabs (Scylla serrata) in a recirculation system. Shelter, as one of the abiotic factors, plays a pivotal role in reducing death caused by cannibalism of crab and suppressing the stress levels of biota. Recirculation Aquaculture System (RAS), with the culture box capacity 60 L supported by the shelters, is predicted to produce the best physiological and growth responses of mud crabs. This present study aims to evaluate the effect of shelter addition in the environmental recirculation system on the physiological responses and production of mud crabs S. serrata with a density of 10 crabs per one culture box containing 60 L of seawater. The research was set up with three treatments of shelter addition, i.e., two shelters (S2), four shelters (S4), six shelters (S6), and control without shelter (C). Results showed that S6 was the best treatment with a survival rate of 73.33 ± 5.8%, a specific growth rate of 0.886 ± 0.014%, the growth rate of carapace width 0.024 ± 0.004 cm/day, and the lowest feed conversion ratio than those of other treatments. S6 treatment significantly influenced the total hemocyte count of crabs at the early cultivation (P <0.05). Addition of six shelters could optimize the growth of mud crabs with a stocking density of 10 crabs in one culture box. 

scholarly journals Threshold and adaptation in Phycomyces. Their interrelation and regulation by light.

1984 ◽  
Vol 84 (1) ◽  
pp. 119-132 ◽  
Author(s):  
P Galland ◽  
V E Russo
Keyword(s):  
Growth Rate ◽  
Dark Adaptation ◽  
Type Strain ◽  
Wild Type Strain ◽  
Light Sensitivity ◽  
Growth Conditions ◽  
Continuous Illumination ◽  
Growth Responses ◽  
Wild Type

The absolute light sensitivity of Phycomyces sporangiophores was determined by analyzing the intensity dependence of the phototropic bending rate and of the light growth and dark growth responses to step changes of the intensity. We found that the different methods give approximately the same results for the wild-type strain, as well as for several behavioral mutants with defects in the genes madA, madB, and madC. A crucial factor in the determination of thresholds is the light intensity at which the strains grow during the 4 d after inoculation and prior to the experiment. When the wild-type strain grows in the dark, its threshold for the bending rate is 10(-9) W X m-2, compared with 2 X 10(-7) W X m-2 when it is grown under continuous illumination. Further, the maximal bending rate is twice as high in dark-grown strains. This phenomenon is further complicated by the fact that the diameter and growth rate of the sporangiophores also depend on the illumination conditions prior to the experiment: light-grown sporangiophores have an increased diameter and an increased growth rate compared with dark-grown ones. Some of the behavioral mutants, however, are indifferent to this form of light control. Another factor that is controlled by the growth conditions is adaptation: the kinetics of dark adaptation are slower in light-grown sporangiophores than in dark-grown ones. We found empirically a positive correlation between the slower dark adaptation constant and the threshold of the bending rate, which shows that the two underlying phenomena are functionally related.

Growth responses of cultivars of subterranean clover to temperature, plant density and nitrate supply

1990 ◽  
Vol 41 (1) ◽  
pp. 101 ◽  
Author(s):  
JH Silsbury ◽  
TW Hancock
Keyword(s):  
Growth Rate ◽  
Low Temperature ◽  
Plant Density ◽  
Subterranean Clover ◽  
Growth Conditions ◽  
High Density ◽  
Growth Responses ◽  
Mineral N ◽  
Nitrate Supply ◽  
Temperature Interaction

Six cultivars of subterranean clover were compared for growth as swards under controlled conditions in six separate experiments. Conditions common to all experiments were: 400 8mol quanta m-2 s-1 and 12 h day: 12 h night. The variable regimens were: 2 000 or 12 000 plants m-2 ('low' and 'high' density), 10 to 20�C; and no mineral N (0 mM) or N supplied as a 7.5 mM NO3- solution. Growth responses to these conditions were tested by sequential harvesting for dry matter and the fitting of linear and quadratic regression models. Special attention was given to testing for differential responses by cultivars to temperature. All cultivars except 'Woogenellup' grew about 20% faster when NO3- was supplied in the nutrient solution than when the N was derived entirely from N2 fixation under the 0mM treatment. Crop growth rate at 20�C was about double that at 10�C at low density, but at high density the rate at 20�C was 90-95% of that at 10�C. Cultivars differed significantly in growth rate but over all conditions, there was a hierarchical order from the highest to the lowest of: 'Clare', 'Woogenellup', 'Yarloop', 'Mt. Barker', 'Daliak' and 'Geraldton'. There was very little evidence of any cultivar by temperature interaction except for 'Woogenellup, which responded to a low temperature of 10�C compared with a 'high' of 20�C better than the other cultivars. The importance of seed size as a factor influencing the early growth of a subterranean clover sward was emphasized where swards established from large seeds of 'Mt. Barker' grew faster than where small seeds were used. 'Clare' was a highly productive cultivar under all growth conditions. It is concluded that the growth rates of swards of subterranean clover established at seedling densities in excess of 5000 plants m-2 are less sensitive to a low temperature of 10�C than are those established at more conventional densities.

scholarly journals Sprucing up the mixedwoods: growth response of white spruce (Picea glauca) to partial cutting in the eastern Canadian boreal forest

2016 ◽  
Vol 46 (10) ◽  
pp. 1205-1215 ◽  
Author(s):  
Jessica Smith ◽  
Brian D. Harvey ◽  
Ahmed Koubaa ◽  
Suzanne Brais ◽  
Marc J. Mazerolle
Keyword(s):  
Growth Rate ◽  
Populus Tremuloides ◽  
Picea Glauca ◽  
Growth Response ◽  
Volume Growth ◽  
White Spruce ◽  
Growth Responses ◽  
Eastern Canada ◽  
Partial Cutting ◽  
Mixed Effect

Mixed-species stands present a number of opportunities for and challenges to forest managers. Boreal mixedwood stands in eastern Canada are often characterized by a dominant canopy of shade-intolerant aspen (Populus tremuloides Michx.) with more shade-tolerant conifers in the mid- to sub-canopy layers. Because the aspen and conifer components often attain optimal merchantable sizes at different moments in stand development, there is an interest in developing silvicultural practices that allow partial or total removal of aspen and favour accelerated growth of residual conifers. We tested four partial harvesting treatments in mixed aspen – white spruce (Picea glauca (Moench.) Voss) stands in which different proportions of aspen (0%, 50%, 65%, and 100% basal area) were removed. Ten years after treatments, 72 spruce stems representing dominant, co-dominant, and suppressed social classes were destructively sampled for stem analysis. Using linear mixed effect models, we analyzed growth as a function of treatment intensity, time since treatment, social status, pretreatment growth rate, and neighbourhood competition. Relative to control stands, radial and volume growth responses were detected only in the extreme treatment of 100% aspen removal. In relative terms, suppressed trees showed the greatest magnitude of cumulative growth increase. Compared with control trees, average annual radial and volume increments were, respectively, 23.5% and 7.1% higher for dominant trees, 67.7% and 24.1% higher for co-dominant trees, and 115.8% and 65.6% higher for suppressed trees over the 10 years after treatment. Growth response was proportional to pretreatment growth rate, and among neighbouring trees, only coniferous neighbours had a negative effect on white spruce growth. Our results suggest that in similar mixed-stand conditions, relatively heavy removal of overstory aspen accompanied by thinning of crowded conifers would result in greatest growth response of residual spruce stems.

A cadmium-tolerant strain of Neocosmospora vasinfecta shows reduced cadmium influx

1991 ◽  
Vol 69 (6) ◽  
pp. 1296-1301 ◽  
Author(s):  
K. Budd
Keyword(s):  
Growth Rate ◽  
Specific Growth Rate ◽  
Growth Response ◽  
Specific Growth ◽  
Cadmium Toxicity ◽  
Recovery Phase ◽  
Growth Responses ◽  
Cadmium Level ◽  
Key Words Cadmium ◽  
Net Uptake

Neocosmospora vasinfecta was grown in a defined liquid medium and its growth responses to CdSO4 were measured. The specific growth rate of mycelium not previously exposed to cadmium was reduced to 50% by 51 μM cadmium. The growth response to concentrations of cadmium above 50 μM was complex, showing declining and then recovery phases. Inoculum taken from a culture grown to the recovery phase in presence of 100 μM cadmium was cadmium tolerant; a cadmium level of 420 μM was required to reduce its specific growth rate by 50%. Tolerance was not lost by growth in the absence of cadmium. The tolerant mycelium showed markedly reduced net uptake of cadmium as compared with the normal (cadmium sensitive) mycelium. This reduction was due to a decrease in the unidirectional influx of cadmium, with little or no change in efflux. Cadmium toxicity in the normal mycelium was strongly antagonized by calcium but only weakly by manganese or zinc. Calcium also inhibited the uptake of cadmium. Key words: cadmium, calcium, Neocosmospora, tolerance, toxicity, transport.

Preparation and characterization of epitaxial iron oxide films

1998 ◽  
Vol 13 (7) ◽  
pp. 2003-2014 ◽  
Author(s):  
Y. Gao ◽  
Y. J. Kim ◽  
S. A. Chambers
Keyword(s):  
Growth Rate ◽  
Iron Oxide ◽  
Oxygen Plasma ◽  
Film Surface ◽  
Surface Region ◽  
Growth Conditions ◽  
Epitaxial Films ◽  
Pure Phase ◽  
Iron Oxide Films

Well-ordered, pure-phase epitaxial films of FeO, Fe3O4, and γ–Fe2O3 were prepared on MgO(001) by oxygen-plasma-assisted MBE. The stoichiometries of these thin films were controlled by varying the growth rate and oxygen partial pressure. Selective growth of γ–Fe2O3 and α–Fe2O3 was achieved by controlling the growth conditions in conjunction with the choice of appropriate substrates. Growth of the iron oxide epitaxial films on MgO at ≥350 °C is accompanied by significant Mg outdiffusion. The FeO(001) film surface exhibits a (2 × 2) reconstruction, which is accompanied by a significant amount of Fe3+ in the surface region. Fe3O4 (001) has been found to reconstruct to a structure. γ–Fe23 (001) film surface is unreconstructed.

Growth responses in red deer hinds from 16-24 months of age when fed two energy levels during their second winter

1998 ◽  
Vol 1998 ◽  
pp. 141-141
Author(s):  
M H Davies ◽  
D W Deakin
Keyword(s):  
Growth Response ◽  
Red Deer ◽  
Energy Levels ◽  
Growth Restriction ◽  
Growth Responses ◽  
Wide Range ◽  
Feeding Regimes ◽  
Cost Of Production ◽  
Red Meats

It is important that venison competes with other red meats in efficiency and cost of production. The growth responses of farmed red deer during the first 15-18 months of life have been well defined under a wide range of feeding and daylength regimes (Davies, 1995). However there is a need to examine less intensive systems of production which aim to maximise growth from grazed grass, following various growth-restriction feeding regimes during winter. The objective of this experiment was to quantify the growth response in 16-24 month old hinds fed two contrasting feeding regimes during their second winter, followed by a period at pasture.

Emission characteristics of GaInN/GaN multiple quantum shell nanowire-based LEDs with different p-GaN growth conditions

Nanophotonics ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Sae Katsuro ◽  
Weifang Lu ◽  
Kazuma Ito ◽  
Nanami Nakayama ◽  
Naoki Sone ◽  
...  
Keyword(s):  
Growth Rate ◽  
Shell Growth ◽  
Light Output ◽  
High Growth ◽  
Growth Conditions ◽  
High Growth Rate ◽  
Current Injection ◽  
Emission Characteristics ◽  
Multiple Quantum ◽  
Plane Region

Abstract Improving current injection into r- and m-planes of nanowires (NWs) is essential to realizing efficient GaInN/GaN multiple quantum shell (MQS) NW-based light-emitting diodes (LEDs). Here, we present the effects of different p-GaN shell growth conditions on the emission characteristics of MQS NW-LEDs. Firstly, a comparison between cathodoluminescence (CL) and electroluminescence (EL) spectra indicates that the emission in NW-LEDs originates from the top region of the NWs. By growing thick p-GaN shells, the variable emission peak at around 600 nm and degradation of the light output of the NW-LEDs are elaborated, which is attributable to the localization of current in the c-plane region with various In-rich clusters and deep-level defects. Utilizing a high growth rate of p-GaN shell, an increased r-plane and a reduced c-plane region promote the deposition of indium tin oxide layer over the entire NW. Therefore, the current is effectively injected into both the r- and m-planes of the NW structures. Consequently, the light output and EL peak intensity of the NW-LEDs are enhanced by factors of 4.3 and 13.8, respectively, under an injection current of 100 mA. Furthermore, scanning transmission electron microscope images demonstrate the suppression of dislocations, triangular defects, and stacking faults at the apex of the p-GaN shell with a high growth rate. Therefore, localization of current injection in nonradiative recombination centers near the c-plane was also inhibited. Our results emphasize the possibility of realizing high efficacy in NW-LEDs via optimal p-GaN shell growth conditions, which is quite promising for application in the long-wavelength region.

The role of nematodes, fungi, bacteria, and abiotic factors in the etiology of apple replant problems in the Granite Belt of Queensland

1994 ◽  
Vol 34 (8) ◽  
pp. 1177 ◽  
Author(s):  
SR Dullahide ◽  
GR Stirling ◽  
A Nikulin ◽  
AM Stirling
Keyword(s):  
Abiotic Factors ◽  
Dry Weight ◽  
Pratylenchus Penetrans ◽  
Growth Responses ◽  
Granite Belt ◽  
Pathogenicity Tests ◽  
Phosphorus And Potassium ◽  
Orchard Soils ◽  
Fusarium Tricinctum

Investigations of apple replant failure in the Granite Belt suggested that the problem had a complex etiology. Soil fertility was an important factor because apple seedlings grew best in replant soils with high levels of nitrogen, phosphorus, and potassium. Consistent improvements in the growth of apple seedlings were obtained when typical orchard soils were treated with fenamiphos, confirming that lesion nematode was also an important component of the disease complex. Pratylenchus penetrans had been recognised as a pathogen of apples, and pathogenicity tests showed that P. jordanensis, another species widely distributed in the Granite Belt, had similar effects. Growth responses of apple seedlings were greater when soil was pasteurised than when it was treated with fenamiphos, suggesting that root pathogens other than nematodes were involved in apple replant failure. However, the primary cause probably differed between orchards because soils did not respond in the same manner to pasteurisation and nematicide treatments. Pathogenicity tests with 14 bacteria associated with apple roots showed no effect on the growth of apple seedlings. However, Fusarium tricinctum, Cylindrocarpon destructans, and Pythium sp. were implicated in the problem because they were consistently recovered from discoloured roots. In a factorial experiment involving nematodes and fungi in pots, P. jordanensis, P. penetrans, E. tricinctum, and C. destructans reduced the dry weight of apple roots but there was no interaction between nematodes and fungi.

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