scholarly journals A temperature response function for modeling leaf growth and development of the African violet (Saintpaulia ionantha Wendl.)

2004 ◽  
Vol 34 (1) ◽  
pp. 55-62 ◽  
Author(s):  
Nereu Augusto Streck
Keyword(s):  
Response Function ◽  
Growth And Development ◽  
Leaf Growth ◽  
Temperature Response ◽  
Simulation Models ◽  
African Violet ◽  
Appearance Rate ◽  
Leaf Appearance Rate ◽  
Leaf Appearance ◽  
Cardinal Temperatures

Response functions used in crop simulation models are usually different for different physiological processes and cultivars, resulting in many unknown coefficients in the response functions. This is the case of African violet (Saintpaulia ionantha Wendl.), where a generalized temperature response for leaf growth and development has not been developed yet. The objective of this study was to develop a generalized nonlinear temperature response function for leaf appearance rate and leaf elongation rate in African violet. The nonlinear function has three coefficients, which are the cardinal temperatures (minimum, optimum, and maximum temperatures). These coefficients were defined as 10, 24, and 33ºC, based on the cardinal temperatures of other tropical species. Data of temperature response of leaf appearance rate and leaf elongation rate in African violet, cultivar Utah, at different light levels, which are from published research, were used as independent data for evaluating the performance of the nonlinear temperature response function. The results showed that a generalized nonlinear response function can be used to describe the temperature response of leaf growth and development in African violet. These results imply that a reduction in the number of input data required in African violet simulation models is possible.

Temperature response function for leaf appearance rate in wheat and corn

1999 ◽  
Vol 79 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Y. W. Jame ◽  
H. W. Cutforth ◽  
J. T. Ritchie
Keyword(s):  
Response Function ◽  
Plant Development ◽  
Full Range ◽  
Beta Function ◽  
Temperature Response ◽  
Base Temperature ◽  
Appearance Rate ◽  
Leaf Appearance Rate ◽  
Leaf Appearance ◽  
Rate Of Leaf Appearance

The ability to predict leaf appearance would enhance our capability of modeling plant development and the rate of leaf area expansion. Many crop models use the constant thermal time for successive leaf tip appearance (which is often termed a phyllochron) as one model parameter to predict total number of leaves and date of anthesis. However, many researchers have found that phyllochron is not constant, but is dependent upon environment. The problem could be related to the simplified assumption that the daily leaf appearance rate is linearly related to temperature (and hence, phyllochron is constant, independent of temperature). In reality, the temperature response function for the development of a biological system is nonlinear. Thus, we fitted daily leaf appearance rate–temperature relationships obtained from growth room studies for both wheat (Triticum aestivum) and corn (Zea mays L.) to a nonlinear beta function with 0 °C as the base temperature and 42 °C as the upper critical temperature. The function described the relationships very well over the full range of temperatures for plant development. Other variables that are used to describe the duration and rate of leaf appearance, such as calendar days, phyllochron, and thermal rate of leaf appearance, are related to the daily leaf appearance rate, eliminating the need to develop various mathematical functions to independently describe the response of these variables to temperature. Because of the nonlinear nature of the temperature response function, we demonstrated that more accurate determinations of daily leaf appearance rates can be achieved by calculating rates over relatively short periods (i.e., hourly) and summing these to get the mean daily rate. Many environmental factors other than temperature also affect leaf appearance rate. However, once the proper temperature response function for leaf appearance rate is determined, it is much easier to determine when and how other factors are involved to modify the leaf appearance rate under a given environment.Key words: Temperature, leaf appearance rate, phyllochron, wheat, corn, beta function

scholarly journals 591 MelonMan: A Simple Phenology Model of Muskmelon Development

HortScience ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 498D-498
Author(s):  
J.T. Baker ◽  
D.I. Leskovar ◽  
V.R. Reddy ◽  
F.J. Dainello
Keyword(s):  
Threshold Temperature ◽  
Time Interval ◽  
Base Temperature ◽  
Node Number ◽  
Appearance Rate ◽  
Leaf Appearance Rate ◽  
Final Yield ◽  
Phenology Model ◽  
Leaf Appearance ◽  
Cardinal Temperatures

A temperature experiment with two cultivars of muskmelon (`Gold Rush' and `Mission') was conducted in growth chambers to determine how main vine leaf appearance rates responded to temperature. We identified three cardinal temperatures for leaf appearance rate: the base temperature (10 °C) at which leaf appearance rate was zero, an optimum temperature where leaf appearance rate was at a maximum (34 °C) and an upper threshold temperature (45 °C) where leaf appearance rate returned to zero. Using these three cardinal temperatures, we constructed a simplified thermal unit accumulator for hourly measurements of air temperature. Main vine plastochron interval (PI), thermal time to harvest and final yield was determined for three cultivars of muskmelon (`Explorer', `Goldrush', and `Mission') grown in the field over six transplanting dates. The PI was calculated for each cultivar-transplanting date combination as the reciprocal of the slope of main vine node number vs. accumulated hourly thermal units (Tu). The PI was significantly affected by both cultivar and transplanting date. Final yield was sharply reduced in the last two planting dates, presumably due to high temperature stresses impacting reproductive development. As air temperatures warmed during the field experiment, the time interval from transplanting to 10% final harvest were reduced by between 21 to 28 days among the three cultivars and the first four transplanting dates. Our goal was to construct a simple muskmelon phenology model that could be run with easily obtainable weather station data and used by growers to quantify phenological development and aid in projecting harvest dates. We also wanted to test whether main vine node number was a useful description of vegetative development for muskmelon.

scholarly journals Morphogenesis of stockpiled Marandu, Piatã, Xaraés and Paiaguás brachiariagrass cultivars

2021 ◽  
Vol 73 (6) ◽  
pp. 1413-1421
Author(s):  
M.E.R. Santos ◽  
I.C. Ferreira ◽  
B.H.R. Carvalho ◽  
G.O. Rocha ◽  
G.S. Borges ◽  
...  
Keyword(s):  
Leaf Growth ◽  
Stem Elongation ◽  
Elongation Rate ◽  
Pasture Management ◽  
Randomized Design ◽  
Appearance Rate ◽  
Leaf Appearance Rate ◽  
Completely Randomized Design ◽  
Urochloa Brizantha ◽  
Leaf Appearance

ABSTRACT The objective this study was to identify differences in the morphogenic patterns of four Urochloa brizantha cultivars (marandu, piatã, xaraés and paiaguás grasses) during the stockpiling period. A completely randomized design was used, with three replications, in experimental plots of 9m². The evaluations took place over 2 years. The grasses were stockpiled for 92 (Year 1) and 95 (Year 2) days. The leaf appearance rate of paiaguás grass was higher, compared to other grasses. In Year 1, the stem elongation rate of xaraés grass was higher than other grasses. At the end of stockpiling period of Year 1, the tiller population density (TPD) was higher in the paiaguás grass, intermediate in the xaraés and marandu grasses and lower in the piatã grass. At the end of the stockpiling period in Year 2, TPD was higher in the paiaguás grass canopy, intermediate in the marandu and piatã grasses canopies, and lower in the xaraés grass canopy. Paiaguás grass has greater leaf growth during the stockpiling period and is therefore suitable for use under stockpiled grazing. Xaraés grass has high stem elongation during the stockpiling period, which is why its use under stockpiled grazing must be accompanied by adjustments in pasture management.

scholarly journals Quantitative genetic analysis in Phalaris tuberosa III. Maternal effects on seedling growth and development

1971 ◽  
Vol 18 (3) ◽  
pp. 245-253 ◽  
Author(s):  
B. D. H. Latter
Keyword(s):  
Seed Size ◽  
Maternal Effects ◽  
Seedling Growth ◽  
Growth And Development ◽  
Female Parent ◽  
Appearance Rate ◽  
Leaf Appearance Rate ◽  
Commercial Population ◽  
Leaf Appearance ◽  
Individual Seedling

SUMMARYThe genetic basis of variation in rate of seedling growth, and development has been examined in the Australian commercial population of Phalaris tuberosa. A model of additive genetic maternal effects has been used, with seed weight of the female parent as an index of maternal ability. Rate of leaf appearance, rate of tillering and growth per tiller are all genetically variable in the population, with estimated heritabilities of 0·36, 0·23 and 0·34 respectively on an individual seedling basis. Total seedling growth has a lower heritability (0·17), due to a negative genetic correlation between tiller production and growth per tiller ( − 0·46). These two components have also been shown to be subject to qualitatively different seed size maternal effects. Genetic differences in seed size in the female parent have been found to influence growth per tiller, while environmental differences in seed size affect primarily the rates of leaf appearance and tiller production.

scholarly journals Morphogenetic characteristics of three Brachiaria brizantha cultivars submitted to nitrogen fertilization

2013 ◽  
Vol 85 (1) ◽  
pp. 371-377 ◽  
Author(s):  
Marcos F Silva ◽  
Edson M. V Porto ◽  
Dorismar D Alves ◽  
Cláudio M.T Vitor ◽  
Ignacio Aspiazú
Keyword(s):  
Nitrogen Fertilization ◽  
Leaf Blade ◽  
Elongation Rate ◽  
Leaf Elongation ◽  
Brachiaria Brizantha ◽  
Nitrogen Levels ◽  
Appearance Rate ◽  
Leaf Elongation Rate ◽  
Leaf Appearance Rate ◽  
Leaf Appearance

This study aims to evaluate the morphogenetic characteristics of three cultivars of Brachiaria brizantha subjected to nitrogen fertilization. The design was a randomized block in factorial arrangement 4x3; three cultivars of B. brizantha - Marandu, Piatã, Xaraés and four nitrogen levels - 0, 80, 160 and 240 kg/ha, with three replications. The experimental units consisted of plastic pots filled with 5 dm3 of soil. Thereupon the establishment fertilization, varieties were sowed directly in the pots, leaving, after thinning, five plants per pot. Forty-five days after planting, it was done a standardization cut at 10 cm tall. Nitrogen levels were distributed according to the treatments, divided in three applications. The morphogenetic characteristics were evaluated in three tillers per sampling unit and data were submitted to analysis of variance and regression. For all evaluated characteristics there was no interaction between factors cultivar and nitrogen levels, verifying only the effects of nitrogen on the variables leaf appearance rate and phyllochron. The dose 240 kg/ha of N corresponds to the greater leaf appearance rate. Cultivar Marandu shows the higher leaf blade: pseudostem and ratio of leaf elongation rate and elongation pseudostem, which favors higher forage quality.

scholarly journals Contrasting phenotypes emerging from stable rules: A model based on self-regulated control loops captures the dynamics of shoot extension in contrasting maize phenotypes

2019 ◽  
Vol 126 (4) ◽  
pp. 615-633 ◽  
Author(s):  
T Vidal ◽  
B Andrieu
Keyword(s):  
Initial Conditions ◽  
Growth Conditions ◽  
Internal Variables ◽  
Model Parameters ◽  
Crop Models ◽  
Control Loops ◽  
Modelling Framework ◽  
Appearance Rate ◽  
Leaf Appearance Rate ◽  
Leaf Appearance

Abstract Background and Aims The dynamics of plant architecture is a central aspect of plant and crop models. Most models assume that whole shoot development is orchestrated by the leaf appearance rate, which follows a thermal time schedule. However, leaf appearance actually results from leaf extension and taking it as an input hampers our ability to understand shoot construction. The objective of the present study was to assess a modelling framework for grasses, in which the emergence of leaves and other organs is explicitly calculated as a result of their extension. Methods The approach builds on a previous model, which uses a set of rules co-ordinating the timing of development within and between phytomers. We first assessed rule validity for four experimental datasets, including different cultivars, planting densities and environments, and accordingly revised the equations driving the extension of the upper leaves and of internodes. We then fitted model parameters for each dataset and evaluated the ability to simulate the measured phenotypes across time. Finally, we carried out a sensitivity analysis to identify the parameters that had the greatest impact and to investigate model behaviour. Key Results The modified version of the model simulated correctly the contrasting maize phenotypes. Co-ordination rules accounted for the observations in all studied cultivars. Factors with major impact on model output included extension rates, the time of tassel initiation and initial conditions. A large diversity of phenotypes could be simulated. Conclusions This work provides direct experimental evidence for co-ordination rules and illustrates the capacity of the model to represent contrasting phenotypes. These rules play an important role in patterning shoot architecture and some of them need to be assessed further, considering contrasting growth conditions. To make the model more predictive, several parameters could be considered in the future as internal variables driven by plant status.

Leaf tissue remaining after cutting and regrowth in perennial ryegrass

1974 ◽  
Vol 82 (1) ◽  
pp. 165-172 ◽  
Author(s):  
Alison Davies
Keyword(s):  
Growth Rate ◽  
Perennial Ryegrass ◽  
Plant Material ◽  
Shoot Growth ◽  
Leaf Tissue ◽  
Relative Growth ◽  
Appearance Rate ◽  
Leaf Appearance Rate ◽  
Leaf Appearance ◽  
Increased Activity

SUMMARYWhen one or two leaves were removed out of the three or sometimes four present on each tiller of five genotypes of perennial ryegrass grown in nutrient solution, it was found that the relative growth rate (RGR) was not much less than that of untreated plants. The removal of lower leaves had no effect on RGR. Removal of all leaf blades depressed RGR. It is suggested that the results obtained indicate that the plant has the capacity to compensate for loss of leaf tissue by increased activity in the remaining leaves. Leaf appearance rate and tiller production were found to be the attributes most sensitive to the defoliation treatments imposed, and the degree to which leaf appearance rates were affected by defoliation was found to be a good indicator of the regrowth capacity of the different genotypes. Evidence was obtained linking high regrowth potential with high relative increases in the proportion of plant material allocated to new shoot growth.

The effect of grazing severity and fertiliser application during winter on herbage regrowth and quality of perennial ryegrass (Lolium perenne L.)

2007 ◽  
Vol 47 (7) ◽  
pp. 825 ◽  
Author(s):  
J. M. Lee ◽  
D. J. Donaghy ◽  
J. R. Roche
Keyword(s):  
Water Soluble ◽  
Soluble Carbohydrate ◽  
Initial Water ◽  
The Third ◽  
Appearance Rate ◽  
Leaf Appearance Rate ◽  
N Treatment ◽  
Fertiliser Application ◽  
Tiller Density ◽  
Leaf Appearance

The objective of the current study was to quantify the effects of greater herbage residuals in winter on leaf appearance rate, herbage accumulation and quality, and plant energy reserves, as well as quantifying the effects nitrogen (N), or phosphorus (P) and sulfur (S) fertilisers had on the above measures. Ten pasture areas were grazed to different residual masses (1260 ± 101 and 1868 ± 139 kg DM/ha, Severe and Lax, respectively) over five consecutive days by dry dairy cows. Two randomly located subplots within each grazing area were fertilised with either 50 kg N/ha (N treatment) or 50 kg N/ha, 31 kg S/ha plus 26 kg P/ha (N + S + P treatment) on the day immediately following defoliation (day 1), and were compared with a control subplot. Neither growth rate (15.1 ± 8.1 kg DM/ha.day), nor leaf appearance rate (15.1 ± 0.3 days per new leaf) differed between treatments. As a result, herbage accumulated over the 49 days of regrowth was similar across grazing treatments and averaged 726 kg DM/ha. Application of N + S + P tended to increase total herbage accumulated during regrowth compared with either the control or N treatment subplots (860 v. 675 and 643 kg DM/ha, respectively), likely a result of increased tiller density. Swards defoliated more severely had lower initial water-soluble carbohydrate (WSC) concentrations compared with swards laxly defoliated, but this difference had disappeared before appearance of the third new leaf. Herbage quality improved in the Severe treatment subplots after emergence of the third new leaf, with higher digestibility, greater WSC and metabolisable energy, and lower fibre content than in laxly grazed subplots.

Effects of photoperiod on leaf appearance rate and leaf dimensions in winter and spring wheats

1996 ◽  
Vol 76 (1) ◽  
pp. 43-50 ◽  
Author(s):  
S. Pararajasingham ◽  
L. A. Hunt
Keyword(s):  
Leaf Area ◽  
Leaf Length ◽  
Leaf Number ◽  
Dry Matter Accumulation ◽  
Flag Leaves ◽  
Appearance Rate ◽  
Rate Of Increase ◽  
Leaf Appearance Rate ◽  
Leaf Dimensions ◽  
Leaf Appearance

Research on genotypic variation in the response of leaf-area production and expansion to photoperiod in wheat is limited. Growth-cabinet experiments using four spring and four winter wheat (Triticum aestivum L.) cultivars and four photoperiod (8, 12, 16 and 20 h) treatments were thus conducted with the objective of investigating the effect of photoperiod on leaf appearance rate and leaf dimensions. Winter wheats were grown without vernalization. In the spring wheats, flag leaves and spikes were formed under the longer photoperiod (16 and 20 h) treatments, and leaf number increased linearly with time. At the shorter photoperiods, flag leaves and spikes appeared in some cultivars only, and the rate of increase in leaf number decreased in the later stages. Final leaf number was greater at shorter photoperiods. In the winter cultivars, more leaves appeared than in the spring types under the longer photoperiods. For leaves 3–7, leaf number was a linear function of time, with photoperiod and cultivar effects. For one of four spring cultivars, the rate of leaf appearance was greater at 8 h than at 20 h, whereas for three of the winter cultivars the reverse was true. Leaf length increased with leaf number up to at least nodes 5–6 for both spring and winter types but decreased for the later-formed leaves for the spring but not for the winter types. Leaves of plants grown under photoperiods longer than 8 h were longer and broader than those grown under the short photoperiod, and the effect was more pronounced in winter than in spring cultivars. Such genotypic differences in the direct effects of photoperiod on leaf dimensions, which could influence the rates of leaf-area production and dry-matter accumulation under field conditions, emphasize that future studies should incorporate genotypes from different eco-physiological regions and that simulation models of wheat growth and development may need to account for variability in the control of vegetative growth. Key words: Wheat, photoperiod, leaf appearance rate, leaf length, leaf width

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