Effect of constant and fluctuating temperature regimes and seed source on the coleoptile length of tall and semidwarf wheats

1987 ◽  
Vol 27 (1) ◽  
pp. 113 ◽  
Author(s):  
BJ Radford
Keyword(s):  
Environmental Conditions ◽  
Laboratory Experiments ◽  
Seed Source ◽  
Seed Maturation ◽  
Wheat Cultivars ◽  
Coleoptile Length ◽  
Fluctuating Temperature ◽  
Temperature Regimes ◽  
The Mean ◽  
Constant And Fluctuating Temperature

Laboratory experiments were carried out to determine the effects of constant and fluctuating temperature regimes on the final coleoptile length of 8 wheat cultivars (Banks, Cook, Gatcher, Hartog, Kite, Oxley, Shortim and Spica) and the effect of environmental conditions during seed maturation (seed source) on the coleoptile length of 5 cultivars (Banks, Bass, Cook, Kite and Oxley). Mean coleoptile length decreased from 10.8 cm at 15�C to only 3.1 cm at 35�C, a reduction within this temperature range of 1 cm for every 2.6�C rise in temperature. This indicates that, in warm soil, shallow sowing is necessary for satisfactory wheat establishment. Fluctuating temperatures (� 5�C about the mean) further reduced coleoptile length. The temperature x cultivar interaction was significant, differences among cultivars in coleoptile length occurring more at low than at high temperatures. The mean coleoptile lengths of the 8 cultivars varied from 8.7 to 14.5 cm at 15�C, but only from 2.7 to 3.6 cm at 35�C. Tall wheat cultivars (Gatcher and Spica) generally had longer coleoptiles than the 6 semidwarf cultivars. Tall wheats also had near-maximum coleoptile length at a wider range of temperatures than semidwarfs. Different environmental conditions during seed maturation (glasshouse v. field) changed the ranking of cultivars with respect to coleoptile length. The coleoptiles of Cook and Oxley were significantly longer when seed was field-ripened rather than glasshouse ripened, while those of Banks, Bass and Kite were similar in length under both ripening environments.

scholarly journals Short term fluctuating temperature alleviates Daphnia stoichiometric constraints

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Esteban Balseiro ◽  
Cecilia Laspoumaderes ◽  
Facundo Smufer ◽  
Laura Wolinski ◽  
Beatriz Modenutti
Keyword(s):  
Nutrient Limitation ◽  
Temperature Fluctuation ◽  
Diel Vertical Migration ◽  
Temperature Treatment ◽  
Short Term ◽  
Fluctuating Temperature ◽  
Rna Content ◽  
Temperature Regimes ◽  
Lake Temperature ◽  
The Mean

AbstractIn this study, we analysed how short term temperature fluctuation interacts with nutrient limitation in the vertical migrating Daphnia commutata. We hypothesize that short term (daily) temperature fluctuation will alleviate nutrient limitation. We carried out experiments analysing growth rates, phosphorus and RNA content of D. commutate grown under four different temperature regimes and two P-limited conditions. Our experiments showed that individuals grown under fluctuating temperature grew more than at the mean temperature. We estimated the expected sizes for the 15 °C treatment based on the Q10 and for the fluctuating temperature treatment. These expected sizes for both treatments resulted well below the observed ones. The P and RNA content of individuals grown at 10 °C were significantly higher than those at 20 °C, and when individuals grown at 10 °C were translocated to 20 °C they exerted an increased growth rate. Our results suggest that, under a regime of diel vertical migration, the temperature alternation would allow migrating organisms to alleviate the effect of severe nutrient limitation maintaining population growth. Under a scenario of global warming, where epilimnetic temperatures will increase, lake temperature will interact with nutrient limitation for consumers, but, organisms may be able to face these changes if they can still regularly move from a cold hypolimnion to a warmer epilimnion.

scholarly journals Effect of temperature on predation by Tasmanian lacewing larvae

2001 ◽  
Vol 54 ◽  
pp. 244-247 ◽  
Author(s):  
S.S. Islam ◽  
R.B. Chapman
Keyword(s):  
Larval Development ◽  
Laboratory Study ◽  
Consumption Rate ◽  
Effect Of Temperature ◽  
Fluctuating Temperature ◽  
Cabbage Aphid ◽  
Larval Behaviour ◽  
Temperature Regimes ◽  
Consumption Rates ◽  
Constant And Fluctuating Temperature

A laboratory study investigated the predation and development rates of Tasmanian lacewing larvae (Micromus tasmaniae) under constant and fluctuating temperature regimes Larval development and consumption of second instar cabbage aphid (Brevicoryne brassicae) increased linearly with constant temperatures between 1030C Under fluctuating daily temperatures (1025C) development and consumption rates were equivalent to those found at a constant 25C Larvae consumed more aphids during later instars and a maximum consumption rate of approximately 10 aphids per day was recorded Some aspects of larval behaviour are described

COLONY OF THE FUNGUS Aspergillus oryzae AND SELF-AFFINE FRACTAL GEOMETRY OF GROWTH FRONTS

Fractals ◽  
1993 ◽  
Vol 01 (01) ◽  
pp. 11-19 ◽  
Author(s):  
SHU MATSUURA ◽  
SASUKE MIYAZIMA
Keyword(s):  
Aspergillus Oryzae ◽  
Environmental Conditions ◽  
Fractal Geometry ◽  
Nutrient Concentration ◽  
Incubation Temperature ◽  
Characteristic Exponent ◽  
Growth Front ◽  
Favorable Condition ◽  
The Self ◽  
The Mean

A variety of colony shapes of the fungus Aspergillus oryzae under varying environmental conditions such as the nutrient concentration, medium stiffness and incubation temperature are obtained, ranging from a homogeneous Eden-like to a ramified DLA-like pattern. The roughness σ(l, h) of the growth front of the band-shaped colony, where h is the mean front height within l of the horizontal range, satisfies the self-affine fractal relation under favorable environmental conditions. In the most favorable condition of our experiments, its characteristic exponent is found to be a little larger than that of the 2-dimensional Eden model.

scholarly journals A novel approach for nitrogen diagnosis of wheat canopies digital images by mobile phones based on histogram

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Xin Qi ◽  
Yanan Zhao ◽  
Yufang Huang ◽  
Yang Wang ◽  
Wei Qin ◽  
...  
Keyword(s):  
Neural Network ◽  
Mobile Phones ◽  
Mean Value ◽  
Wheat Cultivars ◽  
N Content ◽  
Color Parameters ◽  
The Neural Network ◽  
The Mean ◽  
Leaf N Content ◽  
Leaf N

AbstractThe accurate and nondestructive assessment of leaf nitrogen (N) is very important for N management in winter wheat fields. Mobile phones are now being used as an additional N diagnostic tool. To overcome the drawbacks of traditional digital camera diagnostic methods, a histogram-based method was proposed and compared with the traditional methods. Here, the field N level of six different wheat cultivars was assessed to obtain canopy images, leaf N content, and yield. The stability and accuracy of the index histogram and index mean value of the canopy images in different wheat cultivars were compared based on their correlation with leaf N and yield, following which the best diagnosis and prediction model was selected using the neural network model. The results showed that N application significantly affected the leaf N content and yield of wheat, as well as the hue of the canopy images and plant coverage. Compared with the mean value of the canopy image color parameters, the histogram could reflect both the crop coverage and the overall color information. The histogram thus had a high linear correlation with leaf N content and yield and a relatively stable correlation across different growth stages. Peak b of the histogram changed with the increase in leaf N content during the reviving stage of wheat. The histogram of the canopy image color parameters had a good correlation with leaf N content and yield. Through the neural network training and estimation model, the root mean square error (RMSE) and the mean absolute percentage error (MAPE) of the estimated and measured values of leaf N content and yield were smaller for the index histogram (0.465, 9.65%, and 465.12, 5.5% respectively) than the index mean value of the canopy images (0.526, 12.53% and 593.52, 7.83% respectively), suggesting a good fit for the index histogram image color and robustness in estimating N content and yield. Hence, the use of the histogram model with a smartphone has great potential application in N diagnosis and prediction for wheat and other cereal crops.

Étude du développement hétéroblastique chez quelques espèces du genre Medicago

1983 ◽  
Vol 61 (8) ◽  
pp. 2212-2223 ◽  
Author(s):  
Catherine Damerval
Keyword(s):  
Environmental Conditions ◽  
Mean Value ◽  
Annual Species ◽  
The Mean ◽  
Shape Changes

Seven foliar types were defined for the first leaf in the heteroblastic development of seven annual species of Medicago L. Among the species, M. aculeata and M. murex have a typical foliar form. There is no relation between the first leaf and the succeeding trifoliolate one. The shape changes of the middle foliole of the trifoliolate leaves during the development allowed to establish a foliar sequence whose mean length was used to suggest an evolutive hierarchy among the taxa. Five quantitative variables were analysed on the first and on the sixth leaf for stability according to environmental conditions; the two stable variables (L/l and L/Pl) have a best discriminant value for the first leaf than for the sixth one. However, intraspecific heterogeneity is high in both cases. A relation between the flowering precocity and the mean value of one of the sixth leaf's variables (that is, the ratio of the length to the width of the foliole limb) was demonstrated in four species only. The heteroblastic development not only allows to establish a relation between foliar stage and physiologic age, but it itself constitutes a very good taxonomic and systematic criterium; it allowed to identify the seven species studied.

scholarly journals Vertical Round Buoyant Jets and Fountains in a Linearly, Density-Stratified Fluid

Fluids ◽  
2020 ◽  
Vol 5 (4) ◽  
pp. 232
Author(s):  
Panos N. Papanicolaou ◽  
George C. Stamoulis
Keyword(s):  
Steady State ◽  
Laboratory Experiments ◽  
Coefficient Function ◽  
Buoyant Jets ◽  
Asymptotic Values ◽  
Entrainment Coefficient ◽  
Source Level ◽  
The Mean ◽  
Negatively Buoyant ◽  
Negatively Buoyant Jets

Turbulent round buoyant jets and fountains issuing vertically into a linearly density-stratified calm ambient have been investigated in a series of laboratory experiments. The terminal (steady-state) height of rise and the mean elevation of subsequent horizontal spreading have been measured in positively buoyant jets (at source level), including pure momentum jets and plumes, as well in momentum-driven negatively buoyant jets (fountains). The results from experiments confirmed the asymptotic analysis that was based on dimensional arguments. The normalized terminal height and spreading elevation with respect to the elevation of injection of momentum-driven (positively) buoyant jets and fountains attained the same asymptotic values. The numerical results from the solution of entrainment equations, using an improved entrainment coefficient function, confirmed the results related to buoyancy dominant flows (plumes), while their predictions in momentum-driven flows were quite low if compared to measurements.

scholarly journals VERTICAL VARIATION OP UNDERTOW IN THE SURF ZONE

1988 ◽  
Vol 1 (21) ◽  
pp. 33 ◽  
Author(s):  
Akio Okayasu ◽  
Tomoya Shibayama ◽  
Kiyoshi Horikawa
Keyword(s):  
Laboratory Experiments ◽  
Eddy Viscosity ◽  
Surf Zone ◽  
Viscosity Coefficient ◽  
Laser Doppler Velocimeter ◽  
Vertical Variation ◽  
Two Component ◽  
The Mean ◽  
Eddy Viscosity Coefficient ◽  
The Vertical Distribution

In order to establish a model of the vertical distribution of the undertow, laboratory experiments were performed on uniform slopes of 1/20 and 1/30. The turbulent velocity in the surf zone including the area close to the bottom was measured by using a two-component laser doppler velocimeter. The distributions of the mean Reynolds stress and the mean eddy viscosity coefficient were calculated. Based on the experimental results, a model to predict the vertical profile of the undertow was presented.

scholarly journals Grain filling parameters in high-yielding ns wheat cultivars

2008 ◽  
pp. 53-58
Author(s):  
Milka Brdar ◽  
Marija Kraljevic-Balalic ◽  
Borislav Kobiljski
Keyword(s):  
Multivariate Analysis ◽  
Nonlinear Regression ◽  
Environmental Conditions ◽  
Dry Weight ◽  
Grain Filling ◽  
Grain Weight ◽  
Cultivar Differences ◽  
Wheat Cultivars ◽  
Estimated Parameters ◽  
Grain Filling Duration

Grain yield of wheat is dependent on grain weight, which is the result of grain filling duration and rate. The study was undertaken to examine the relation between grain weight and rate and duration of grain filling in five high-yielding NS wheat cultivars. Stepwise multivariate analysis of nonlinear regression estimated grain filling parameters was used to examine cultivar differences in grain filling. On the basis of three-year average, the highest grain dry weight had cultivar Renesansa, and the lightest grains were measured for cultivar Evropa 90. Stepwise multivariate analysis indicated that all three nonlinear regression estimated parameters (grain weight, rate and duration of grain filling) were equally important in characterizing the grain filling curves of the cultivars studied, although sequence of their significance varied in different years, which is probably caused by different environmental conditions in three years of experiment.

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