scholarly journals Barley development as affected by rate of change of photoperiod

1995 ◽  
Vol 124 (3) ◽  
pp. 379-388 ◽  
Author(s):  
G. C. Kernich ◽  
G. A. Slafer ◽  
G. M. Halloran
Keyword(s):  
Spring Barley ◽  
Seedling Emergence ◽  
Rate Of Change ◽  
Leaf Number ◽  
Spikelet Number ◽  
Photoperiod Regime ◽  
Leaf Emergence ◽  
Linear Relationships ◽  
Leaf Appearance ◽  
Rate Of Leaf Appearance

SUMMARYThe rate of leaf appearance of barley varies substantially with time of sowing. This variation has been related to both the length and the rate of change of photoperiod at the time of plant emergence. An outdoor pot experiment was conducted to test if rate of change of photoperiod directly affects phasic development and rate of leaf emergence of spring barley. Two photoperiod-sensitive cultivars (Bandulla and Galleon) were subjected to five photoperiod regimes: two constant photoperiods, of 14 and 15·5 h, and three different rates of change of photoperiod of c. 2, 9 and 13 min/day from seedling emergence to awn initiation.Photoperiod treatments significantly affected the duration from seedling emergence to awn initiation in both cultivars. Rate of change of photoperiod did not affect the rate of development towards awn initiation independently of the absolute daylength it produced. Although Bandulla had a longer duration than Galleon at any photoperiod regime, the cultivars did not vary in their sensitivity to photoperiod. When this phase was divided into the leaf initiation (LI) and spikelet initiation (SI) phases, it was evident that the sensitivity to photoperiod was not constant, being in general higher during the SI than during the LI phase. However, the magnitude of the change in sensitivity was cultivar-dependent, indicating that sensitivity to photoperiod during the different phases could be under independent genetic control.Final numbers of primordia (leaves together with maximum spikelet number) were negatively affected by increasing photoperiods, but once again, there was no evidence of any effect of the rate of change of photoperiod which was independent of the average photoperiod. Both cultivars showed similar sensitivities for final leaf number but maximum spikelet number was more sensitive to photoperiod in Galleon than in Bandulla.Highly significant linear relationships between leaf number and thermal time were found for all combinations of cultivars and photoperiod regimes (r2 > 0·98). The rate of leaf appearance (RLA) was similar for both cultivars (c. 0·0185 leaves/°Cd) and did not alter during plant development or in response to the change in photoperiod at awn initiation. The range in RLA was greater for Galleon (0·0170–0·0205 leaves/°Cd) than for Bandulla (0·0173–0·0186 leaves/°Cd). Neither of these cultivars exhibited a significant relationship between rate of leaf emergence and photoperiod or rate of change of photoperiod. The lack of significant relationships between RLA and length or rate of change of photoperiod is in contrast with previous reports using time of sowing as a main treatment.

scholarly journals Effects of nitrogen on development and growth of the leaves of vegetables. 3. Appearance and expansion growth of leaves of spinach

1995 ◽  
Vol 43 (2) ◽  
pp. 247-260
Author(s):  
H. Biemond
Keyword(s):  
Leaf Area ◽  
Leaf Size ◽  
Field Trials ◽  
Leaf Expansion ◽  
Mature Leaf ◽  
Leaf Emergence ◽  
Number Of Leaves ◽  
Leaf Appearance ◽  
Rate Of Leaf Appearance ◽  
Main Factor

In a series of greenhouse and field trials, spinach cv. Trias plants were supplied with different amounts of N fertilizer in various split applications. Rates of leaf emergence and expansion were recorded, as well as final leaf size. The rate of leaf appearance varied between 0.16 and 0.57/day across experiments, but was hardly affected by N treatment. The rate of leaf expansion and mature leaf area increased with leaf number, reaching maximum values at leaf pair 3+4 or 5+6 and decreasing subsequently. Both characteristics were positively correlated with N supply. The duration of expansion was not influenced by N treatments and varied between 15 and 30 days in most experiments. The rate of leaf expansion was the main factor determining mature leaf size. Specific leaf area over all green leaves slowly decreased with time in most experiments and was around 300 cmsuperscript 2/g. As the differences in the number of leaves were small, the differences in total green leaf area per plant resulted from differences in the areas of individual mature leaves.

Plant development of triticale cv. Lasko at different sowing dates

1998 ◽  
Vol 130 (3) ◽  
pp. 297-306 ◽  
Author(s):  
R. E. L. NAYLOR ◽  
J. SU
Keyword(s):  
Stem Elongation ◽  
Seedling Emergence ◽  
Sowing Date ◽  
Thermal Time ◽  
Development Stages ◽  
Leaf Emergence ◽  
Sowing Dates ◽  
Time Requirements ◽  
Leaf Appearance ◽  
Double Ridge

The progress of leaf emergence, external morphology and apical development stages were recorded in sowings of triticale (cv. Lasko) made from February to November 1990 at Aberdeen (57° N). Leaf appearance and the number of primordia were related to thermal time (above a base of 0°C) except when photoperiods were <c. 11 h. The thermal time per phyllochron varied between leaves and the combined times for all the phyllochrons at a particular sowing accounted for the apparent response of average phyllochron to sowing date. The thermal time requirements for progression to the double ridge stage, terminal spikelet stage, onset of stem elongation and anthesis were similar except where photoperiods of <11 h occurred. The rate of grain primordium production was constant when photoperiod had been increasing at seedling emergence but the rate was reduced when the seedling experienced shortening photoperiods at emergence.

Leaf development in two-row spring barley under long-day and short-day field conditions

2004 ◽  
Vol 84 (2) ◽  
pp. 477-486 ◽  
Author(s):  
B. H. Paynter ◽  
P. E. Juskiw ◽  
J. H. Helm
Keyword(s):  
Hordeum Vulgare ◽  
Western Australia ◽  
Spring Barley ◽  
Linear Regression Analysis ◽  
Leaf Number ◽  
Hordeum Vulgare L ◽  
Short Day ◽  
Leaf Emergence ◽  
Long Day ◽  
Short Days

To gain an understanding of the adaptation of Australian and Canadian barley (Hordeum vulgare L.) cultivars to the environments of western Canada and Western Australia, phyllochron and number of leaves on the mainstem in eight cultivars of two-row, spring barley were examined when sown at two dates in two locations. The locations were a short-day environment at Northam, Western Australia, Australia in 1997 and a long-day environment at Lacombe, Alberta, Canada in 1998. At each location highly significant relationships between leaf number on the mainstem and thermal time were found (r2 > 0.94). Using linear estimates, the phyllochron of barley under short days was longer than under long days and was correlated to time to awn emergence. Later sowing shortened phyllochron under short days, but generally not under long days. Error messages from the linear regression analysis suggested that residuals were not random for all cultivars. Bilinear models were fitted to those datasets. Bilineal responses were observed under both short and long days, being independent of cultivar, date of seeding, final leaf number, phenological development pattern and time to awn emergence. The occurrence of a bilinear response was also independent of any ontogenetic events. The change in phyllochron occurred between leaves 4–7 at Northam and between leaves 6–9 at Lacombe. The leaf number at which the phyllochron change occurred was positively related to final leaf number and time to awn emergence. The phyllochron of early forming leaves was positively related to time to awn emergence and shorter than later forming leaves. Leaf emergence patterns in spring barley under both long-day and short-day conditions may therefore be linear or bilinear. Key words: barley (spring), Hordeum vulgare L., phyllochron, leaf emergence, daylength

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

Phytomers, phyllochrons, phenology and temperate cereal development

2005 ◽  
Vol 143 (2-3) ◽  
pp. 137-150 ◽  
Author(s):  
G S. McMASTER
Keyword(s):  
Abiotic Factors ◽  
Spring Barley ◽  
Critical Role ◽  
Agricultural Science ◽  
Growth Stages ◽  
Leaf Appearance ◽  
Temperate Cereal ◽  
Rate Of Leaf Appearance ◽  
Key Questions

Extensive research has been conducted on temperate cereal development since the inception of the Journal of Agricultural Science, Cambridge in 1905. This review presents an overview of the orderly and predictable development of wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.). It begins with the concept of building canopies by the formation, growth and senescence of phytomers (the unit comprised of the leaf, axillary bud, node and internode). Morphological naming schemes for uniquely identifying each plant part are then extended to uniquely name each phytomer unit. The role of the phyllochron (rate of leaf appearance) in synchronizing cereal development and phytomer formation is discussed, as is the use of phenology to predict the timing of the formation, growth and senescence of individual components. The complete developmental sequence of the winter wheat shoot apex correlated with growth stages is extended to spring barley. This overview discusses the abiotic factors controlling cereal development, with special attention given to key questions regarding the critical role of temperature. The review concludes with some cautious glances forward to the exciting possibilities for better understanding of mechanisms controlling the phyllochron and phenology being gained from advances in functional genomics and molecular biology.

Leaf emergence rates of wheat in a mediterranean environment

1987 ◽  
Vol 38 (2) ◽  
pp. 455 ◽  
Author(s):  
EJM Kirby ◽  
MW Perry
Keyword(s):  
Field Experiments ◽  
Sowing Date ◽  
Rate Of Change ◽  
Main Stem ◽  
Thermal Time ◽  
Wheat Varieties ◽  
Leaf Emergence ◽  
Sowing Dates ◽  
Zero Rate ◽  
Leaf Appearance

Rates of leaf appearance on the main stem were measured for various wheat varieties for five to ten sowing dates in three field experiments in Western Australia.Rate of leaf appearance was constant in relation to thermal time for any given variety and sowing date, and ranged from 0.0064 to 0.0132 leaves (�C day)-1. Most of this variation could be accounted for as a response to sowing date or rate of change of daylength, although the response was complicated by interactions with variety and year.Because successive measurements were made on the same plants, it was possible to estimate directly the effects of temperature on the rate of leaf emergence. In the three years, mean rates of leaf emergence were 0.008, 0.008 and 0.011 leaves day-1 �C-1 with base temperatures (temperatures at zero rate) of 0.08, -1.2 and 0.4�C respectively. Contrary to expectation, rate of leaf emergence decreased as temperatures increased in late sowings due probably to depression of leaf emergence as daytime temperatures exceeded 25�C.For Gamenya, the only variety common to the three years, the rate of leaf emergence (RLE) on the main stem was related to the rate of change of daylength (-DL, min day-1 negative when daylength shortening) by the equationRLE = 0.00949 + 0.000988 (-DL).For crops emerging in late June (-DL approximately zero) in southern Australia, this implies a constant thermal time for leaf appearance of 105�C day leaf-1.

Phyllochron in Wheat as Affected by Photoperiod Under Two Temperature Regimes

1997 ◽  
Vol 24 (2) ◽  
pp. 151 ◽  
Author(s):  
Gustavo A. Slafer ◽  
H. M. Rawson
Keyword(s):  
Winter Wheat ◽  
Temperature Regime ◽  
Heading Date ◽  
Major Effect ◽  
Leaf Number ◽  
Increased Temperature ◽  
Temperature Regimes ◽  
Leaf Appearance ◽  
Rate Of Leaf Appearance ◽  
Two Temperature

In this paper we describe the effects of photoperiod (9, 12, 15, 17, 19 and 21 h) and temperature (21/17 and 16/12°C) on rate of leaf appearance and phyllochron in two spring wheats, a semi-winter wheat, and a winter wheat. Under long photoperiods only, all leaves on the main culm of a cultivar emerged at a common rate within a temperature regime, so it was acceptable to assign a specific phyllochron to leaves irrespective of their level of insertion. Increased temperature significantly decreased phyllochron, but the degree of this effect differed between cultivars. As photoperiod was shortened below the optimum, phyllochron lengthened marginally and similarly in all varieties (by approximately 0.1 days per hour change in photoperiod). For very short photoperiods this was true only for the first six leaves, whilst for leaves at higher insertions there was a major effect of reducing photoperiod on lengthening phyllochron. The actual daylength required for producing this major effect on phyllochron was cultivar-dependent. These results suggest that, when making predictions of heading date using phyllochron, it may not be acceptable to assume that leaf number and time are always linearly related at shorter photoperiods, particularly when considering leaves at higher insertions.

Development in barley (Hordeum sativum)

1986 ◽  
Vol 107 (1) ◽  
pp. 187-213 ◽  
Author(s):  
J. L. Jones ◽  
E. J. Allen
Keyword(s):  
Spring Barley ◽  
Fixed Number ◽  
Major Influence ◽  
Winter Solstice ◽  
Leaf Emergence ◽  
Linear Relationships ◽  
Spring Equinox ◽  
Wide Range ◽  
Number Of Leaves ◽  
Temperature Rate

SUMMARYFour experiments are reported which studied the effects of date of sowing on the development of winter and spring barley. The first three experiments (1979–80, 1980–1, 1982–3) were carried out at Trefloyne, Tenby and used the varieties Sonja (winter) and Jupiter (spring). The final experiment (1983–4) was carried out in Cambridge using the varieties Igri (winter) and Triumph (spring). A wide range of dates of sowing (August-June) was used and there were considerable differences in temperature between seasons.In both Sonja and Igri, delaying sowing from August to mid-February reduced the number of mainstem leaves but further delay in sowing increased the number of leaves. In Jupiter, delaying sowing until late October had little effect but further delay consistently reduced the number of leaves. In Triumph, delaying sowing reduced final number of leaves over the whole range (October-May).In all experiments rate of leaf emergence was characterized by long periods when leaves emerged linearly with time, despite considerable variation in temperature. The only consistent changes in rate of leaf emergence occurred shortly after each equinox, rates slowing in the autumn and increasing in the spring. Rates of leaf emergence were similar in different seasons and sites for similar periods despite differences in temperature.Initiation of spikolet primordia proceeded linearly with time for most dates of sowing. For winter varieties rates of spikelet initiation increased with delay in sowing provided emergence occurred before the spring equinox. Further delay in sowing decreased the rate of spikelet initiation. In contrast in Jupiter and Triumph the rate increased with each delay in sowing. During periods of low temperature, rate of spikelet initiation slowed but frequently increased to faster rates in succeeding increasing temperatures. Such increasing temperatures had no effect on rate of initiation of later-sown treatments which had not experienced the low temperatures. Effects on spikelet initiation were found when no effects on leaf emergence could be detected.Initiation of spikelet primordia in all varieties appeared to begin when a fixed number of leaves (different in some varieties) had emerged and end when a fixed number of leaves were left to emerge. Delaying sowing in winter varieties until February and in Jupiter over the whole range reduced the number of leaves emerging during spikelet initiation and was the developmental mechanism through which large differences in date of sowing became small differences in date of anthesis (and grain maturity).Attempts to relate development to temperature were unsuccessful and the major influence on development appeared to be daylength. Number of emerged mainstem leaves was the most consistent measure of development over sites, seasons and varieties and for winter varieties was influenced by the direction of change of daylength at emergence. Two positive linear relationships between number of leaves and daylength at emergence were found for the periods from summer to winter solstice and from spring equinox to summer solstice. The slope of the latter relationship was greater than the former. For the period from winter solstice to spring equinox a negative linear relationship between number of leaves and daylength at emergence was found. In Triumph number of leaves decreased with decreasing daylength in the autumn and decreased further with increasing daylength. The effects in Jupiter were less clear but there was evidence of the effect of both daylength at emergence and direction of change on number of leaves.In view of the control of number of leaves exercised by daylength, close negative linear relationships between time from sowing to anthesis and date of sowing were found. The significance of the results for relating agronomic practice to development is discussed.

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