Growth and Developmental Responses of Perennial Ryegrass Grown at Constant Temperature. II. Influence of Light and Temperature on Leaf, Tiller and Root Appearance

1985 ◽  
Vol 12 (1) ◽  
pp. 69 ◽  
Author(s):  
WF Hunt ◽  
VJ Thomas
Keyword(s):  
Perennial Ryegrass ◽  
Root Production ◽  
Exponential Growth Phase ◽  
Temperature Dependent ◽  
Response Curves ◽  
Appearance Rate ◽  
Leaf Appearance ◽  
Developmental Responses ◽  
Root Axis ◽  
Rate Of Leaf Appearance

Spaced plants of perennial ryegrass (Lolium perenne L. cv. Grasslands Ruanui) were grown in nutrient solution under six levels of irradiance at six temperatures (7-33°C). Response curves to light and temperature of leaf, tiller and root appearance rates were determined during the exponential growth phase. Appearance rate responses showed saturation-type kinetics with irradiance, the shape of the response curve being temperature dependent. Light-saturated appearance rates increased with temperature over the 7-17°C range, but were independent of temperature above 20°C. No apparent optimum temperature was found for leaf appearance, root appearance or tillering in the 7-33°C range. The ratios for both tillering/leaf appearance and root appearance/leaf appearance (light-saturated) were notable for their insensitivity to temperature. The results indicate that light and temperature determined the rate of leaf appearance through effects on the rate of assimilate supply and utilization at the stem apex. Leaf appearance rates determined the potential rates for tiller and root axis production through determining the sites available. Low irradiance combined with high temperature reduced tillering below the potential but did not reduce root production.

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.

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 Interactions between two QTLs for time to anthesis on spike development and fertility in wheat

2020 ◽  
Author(s):  
Priyanka A. Basavaraddi ◽  
Roxana Savin ◽  
Luzie U Wingen ◽  
Stefano Bencivenga ◽  
Alexandra M. Przewieslik-Allen ◽  
...  
Keyword(s):  
Physiological Effect ◽  
Fine Tuning ◽  
Appearance Rate ◽  
Spike Development ◽  
Before And After ◽  
Leaf Appearance Rate ◽  
Allelic Status ◽  
Per Se ◽  
Leaf Appearance ◽  
Rate Of Leaf Appearance

AbstractEarliness per se (Eps) genes are reported to be important in fine-tuning flowering time in wheat independently of photoperiod (Ppd) and vernalisation (Vrn). Unlike Ppd and Vrn genes, Eps have relatively small effects and their physiological effect along with chromosomal position are not well defined. We evaluated eight lines derived from crossing Paragon and Baj (late and early flowering respectively), vernalisation insensitive, to study the detailed effects of two newly identified QTLs, Eps-7D and Eps-2B and their interactions under field conditions. The effect of both QTLs were minor but their effect was modulated by the allelic status of the other. While the magnitude of effect of these QTLs on anthesis was similar, they are associated with very different profiles of pre-anthesis development which also depends on their interaction. Eps-7D affected both duration before and after terminal spikelet while not affecting final leaf number (FLN) so Eps-7D-early had a faster rate of leaf appearance. Eps-2B acted more specifically in the early reproductive phase and slightly altered FLN without affecting the leaf appearance rate. Both Eps-7D and 2B affected the spike fertility by altering the rate of floret development and mortality. The effect of the latter was very small but consistent in that the -late allele tended to produced more fertile florets.

Leaf appearance rate and associated characters in some Mexican and Australian wheats

1974 ◽  
Vol 25 (1) ◽  
pp. 1 ◽  
Author(s):  
JR Syme
Keyword(s):  
Yield Potential ◽  
High Yield ◽  
Leaf Production ◽  
Polygenic Control ◽  
Appearance Rate ◽  
Leaf Appearance Rate ◽  
Backcross Populations ◽  
Leaf Appearance ◽  
Rate Of Leaf Appearance ◽  
High Yield Potential

Three Mexican cultivars of high yield potential were compared in four field sowings with three Australian varieties of similar flowering time. The cultivars had different numbers of leaves on the main stem, associated mainly with differences in rate of leaf appearance rather than duration of leaf production. The Mexican cultivars produced leaves more quickly throughout growth, and this was repeated under glasshouse conditions. A fast rate of leaf appearance was associated with more spikelets and with faster tillering. Analysis of parental, F1, F2 and backcross populations of one cross showed leaf production rate to be under polygenic control with moderate heritability.

Sowing date and photoperiod effects on leaf appearance in field-grown wheat

1997 ◽  
Vol 77 (1) ◽  
pp. 23-31 ◽  
Author(s):  
G. K. Hotsonyame ◽  
L. A. Hunt
Keyword(s):  
Air Temperature ◽  
Sowing Date ◽  
Rate Of Change ◽  
Wheat Field ◽  
Sowing Dates ◽  
Appearance Rate ◽  
Leaf Appearance Rate ◽  
Supported Work ◽  
Leaf Appearance ◽  
Rate Of Leaf Appearance

Rate of leaf appearance is a characteristic that can impact on the rate of development of a crop canopy. For wheat (Triticum aestivum L.), it is generally thought to be constant within a sowing date, but to vary among sowing dates. Such variation has been variously attributed to differences in the rate of change of photoperiod, the absolute photoperiod, or the mean air temperature. This study was undertaken to provide further information on the photoperiod and temperature effects on rate of leaf appearance in wheat. Field studies were conducted at Elora, Ontario at five sowing dates under natural and extended (20 h) photoperiod conditions. Two genotypes each of spring and winter wheat were grown under 0 and 150 kg ha−1 nitrogen fertilization. The results indicated that variations in rate of leaf appearance were not due to rate of change in photoperiod or absolute photoperiod at emergence. The change in rate of leaf appearance during a growth cycle was constant when mean air temperature during growth varied in a narrow range (less than 10 °C), but varied when there were wider ranges (over 10 °C) of temperature variation. Rate of leaf appearance was lower for the September seeding, at which time temperatures were around 5 °C, but were quite similar for May, June, July and August seedings even though temperatures ranged from approximately 15 °C (May) to 23 °C (June). The results suggested that the leaf appearance rate–temperature response curve is curvilinear, as found in some growth room studies, and supported work indicating that the phyllochron would depend on the temperature at the time of measurement. Key words: Wheat, photoperiod, temperature, nitrogen, sowing date, leaf appearance rate

Growth and Developmental Responses of Perennial Ryegrass Grown at Constant Temperature. I. Influence of Light and Temperature on Growth and Net Assimilation

1981 ◽  
Vol 8 (2) ◽  
pp. 181 ◽  
Author(s):  
WF Hunt ◽  
G Halligan
Keyword(s):  
Growth Rate ◽  
Leaf Area ◽  
Perennial Ryegrass ◽  
Response Curve ◽  
Maximum Growth ◽  
Area Ratio ◽  
Leaf Area Ratio ◽  
Exponential Growth Phase ◽  
Response Curves ◽  
Net Assimilation

Perennial ryegrass (Lolium perenne L. cv. 'Grasslands Ruanui') plants were grown spaced in nutrient golution under six levels of irradiance at six constant temperatures (7-33°C) to provide growth response curves to light and temperature over a range of growth conditions. Measurements were restricted to the exponential growth phase. Plants showed saturation-type growth kinetics with irradiance but the shape of the light response curve was temperature dependent and, conversely, the shape of the temperature response curve was irradiance dependent. Growth analysis revealed that, at 7, 10, 17 and 20°C, changes in leaf area ratio compensated for changes in net assimilation rate over a range in irradiance for which growth rate was maintained near maximum. At 30 and 33°C, the compensating effect of changes in leaf area ratio was insufficient to maintain near maximum growth at intermediate irradiances. Ontogenetic drifts in specific leaf area and leaf area ratio were compensated for by changes in net assimilation, so that relative growth rate remained constant. The maximum growth at 20°C resulted from a greater partitioning of dry weight to leaf than at lower temperatures, as well as higher net assimilation than at all other temperatures.

scholarly journals Wheat pre-anthesis development as affected by photoperiod sensitivity genes (Ppd-1) under contrasting photoperiods

2018 ◽  
Vol 45 (6) ◽  
pp. 645 ◽  
Author(s):  
Thomas I. Pérez-Gianmarco ◽  
Gustavo A. Slafer ◽  
Fernanda G. González
Keyword(s):  
Developmental Time ◽  
Fine Tuning ◽  
Yield Potential ◽  
Genetic Constitution ◽  
Qualitative Response ◽  
Photoperiod Sensitive ◽  
Photoperiod Sensitivity Genes ◽  
Leaf Appearance ◽  
Developmental Responses ◽  
Rate Of Leaf Appearance

Fine tuning wheat phenology is of paramount importance for adaptation. A better understanding of how genetic constitution modulates the developmental responses during pre-anthesis phases would help to maintain or even increase yield potential as temperature increases due to climate change. The photoperiod-sensitive cultivar Paragon, and four near isogenic lines with different combinations of insensitivity alleles (Ppd-A1a, Ppd-B1a, Ppd-D1a or their triple stack) were evaluated under short (12 h) and long (16 h) photoperiods. Insensitivity alleles decreased time to anthesis and duration of the three pre-anthesis phases (vegetative, early reproductive and late reproductive), following the Ppd-D1a > Ppd-A1a > Ppd-B1a ranking of strength. Stacking them intensified the insensitivity, but had no additive effect over that of Ppd-D1a. The late reproductive phase was the most responsive, even exhibiting a qualitative response. Leaf plastochron was not affected but spikelet plastochron increased according to Ppd-1a ranking of strength. Earlier anthesis resulted from less leaves differentiated and a fine tuning effect of accelerated rate of leaf appearance. None of the alleles affected development exclusively during any particular pre-anthesis phase, which would be ideal for tailoring time to anthesis with specific partitioning of developmental time into particular phases. Other allelic variants should be further tested to this purpose.

scholarly journals Interactions between two QTLs for time to anthesis on spike development and fertility in wheat

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Priyanka A. Basavaraddi ◽  
Roxana Savin ◽  
Luzie U. Wingen ◽  
Stefano Bencivenga ◽  
Alexandra M. Przewieslik-Allen ◽  
...  
Keyword(s):  
Physiological Effect ◽  
Fine Tuning ◽  
Appearance Rate ◽  
Spike Development ◽  
Before And After ◽  
Leaf Appearance Rate ◽  
Allelic Status ◽  
Per Se ◽  
Leaf Appearance ◽  
Rate Of Leaf Appearance

AbstractEarliness per se (Eps) genes are reported to be important in fine-tuning flowering time in wheat independently of photoperiod (Ppd) and vernalisation (Vrn). Unlike Ppd and Vrn genes, Eps have relatively small effects and their physiological effect along with chromosomal position are not well defined. We evaluated eight lines derived from crossing two vernalisation insensitive lines, Paragon and Baj (late and early flowering respectively), to study the detailed effects of two newly identified QTLs, Eps-7D and Eps-2B and their interactions under field conditions. The effect of both QTLs was minor and was affected by the allelic status of the other. While the magnitude of effect of these QTLs on anthesis was similar, they are associated with very different profiles of pre-anthesis development which also depends on their interaction. Eps-7D affected both duration before and after terminal spikelet while not affecting final leaf number (FLN) so Eps-7D-early had a faster rate of leaf appearance. Eps-2B acted more specifically in the early reproductive phase and slightly altered FLN without affecting the leaf appearance rate. Both QTLs affected the spike fertility by altering the rate of floret development and mortality. The effect of Eps-2B was very small but consistent in that -late allele tended to produce more fertile florets.

scholarly journals Modeling leaf appearance rate for Canada Western Red Spring wheat cultivars

2010 ◽  
Vol 90 (4) ◽  
pp. 399-402 ◽  
Author(s):  
H. Wang ◽  
H. Cutforth ◽  
R M DePauw ◽  
T. McCaig ◽  
G. McLeod ◽  
...  
Keyword(s):  
Triticum Aestivum ◽  
Triticum Aestivum L ◽  
Wheat Cultivars ◽  
Canadian Prairies ◽  
Semiarid Environment ◽  
Appearance Rate ◽  
Wheat Leaf ◽  
Leaf Appearance Rate ◽  
Leaf Appearance ◽  
Rate Of Leaf Appearance

The rate of leaf appearance [LAR (d-1)] was observed for two older (Marquis and Neepawa) and two newer (AC Barrie and AC Elsa) Canada Western Red Spring (CWRS) wheat (Triticum aestivum L.) cultivars grown in a semiarid environment on the Canadian prairies for four years. Although the newer cultivars significantly increased yield LAR did not change when compared with the older cultivars. A simulation model developed by Jame et al. (1998a), and using coefficients for Neepawa determined from a previous study adequately predicted LAR for all four cultivars.Key words: Wheat, leaf appearance rate, temperature, daylength, model

Effect of defoliation frequency on an irrigated perennial pasture in northern Victoria 2*Part 1, Aust. J. Agric. Res., 1997, 48, 811 - 17.. Individual plant morphology

1997 ◽  
Vol 48 (6) ◽  
pp. 819 ◽  
Author(s):  
A. R. Lawson ◽  
P. W. G. Sale ◽  
K. B. Kelly
Keyword(s):  
Perennial Ryegrass ◽  
White Clover ◽  
High Rate ◽  
Axillary Bud ◽  
Late Winter ◽  
Individual Plant ◽  
Appearance Rate ◽  
Leaf Appearance Rate ◽  
Defoliation Frequency ◽  
Leaf Appearance

The effect of 5 winter and 2 post-winter defoliation frequencies on the morphology of medium-leafed and large-leafed white clover and perennial ryegrass plants in an irrigated perennial pasture in northern Victoria was investigated. Measurements included leaf appearance rates, axillary bud development and survival, stolon elongation and survival, and tiller production and survival. White clover leaf appearance rate was affected little by either defoliation frequency or cultivar, ranging from 0·4 leaves/week in July to 1·1 leaves/week in February. In contrast, perennial ryegrass leaf appearance rate in the same period ranged from 0·35 to 0·7 leaves/week. Axillary bud production on clover stolons was highest in winter and spring and lowest through summer, and was usually greater in the medium-leafed than in the large-leafed cultivars. When the swards were not defoliated through winter, the rate of bud production was reduced in late winter; this was followed by a high rate of bud production in early spring, resulting in little treatment difference in the number of buds per stolon by mid spring. Bud survival was greater when initiated in winter than in summer. The rate of stolon death in spring was higher in the swards not defoliated during winter and higher in the large-leafed than in the medium-leafed cultivar. These effects were associated with the stolon elongation rate in late winter; the medium-leafed cultivar was unaffected by defoliation frequency, whereas in the large-leafed cultivars the rate of stolon elongation increased as the defoliation interval lengthened and canopy shading increased. Perennial ryegrass tiller production was greater with frequent than infrequent winter or post-winter defoliation, but never exceeded 1·2 daughter tillers/tiller, with 44% of the reproductive tillers failing to replace themselves. The low leaf appearance rate and tiller production of the perennial ryegrass may contribute to its poor competitiveness and persistence in this environment.

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