Changes in Leaf Photosynthesis With Plant Ontogeny and Relationships With Yield Per Ear in Wheat Cultivars and 120 Progeny

1983 ◽  
Vol 10 (6) ◽  
pp. 503 ◽  
Author(s):  
HM Rawson ◽  
JH Hindmarsh ◽  
RA Fischer ◽  
YM Stockman
Keyword(s):  
Carbon Fixation ◽  
Flag Leaf ◽  
Wheat Cultivars ◽  
Leaf Photosynthesis ◽  
Negative Effects ◽  
Photosynthetic Rates ◽  
Leaf Emergence ◽  
Plant Ontogeny ◽  
Rate Of Decline ◽  
Linear Decline

Six wheat cultivars, and 120 random progeny derived from composite crosses among these cultivars and 10 others, were grown in a glasshouse and changes in photosynthesis of the main-shoot leaves determined throughout ontogeny. Photosynthetic rates for each leaf generally showed a short-term rise after ligule emergence, a plateau, and then a linear decline as the leaf aged. Both peak photosynthesis, and the rates of reduction in photosynthesis with aging, increased with successive leaves, and then either stabilized or declined in the upper leaf positions. Leaves also increased in area in a power progression with plant ontogeny. The combined effect of these factors was that successive leaves fixed progressively more carbon during their lives. Leaf emergence was essentially linear with time. Fast leaf emergence was linked with small leaves and a greater final leaf number. Whilst there was a negative correlation between area per leaf and photosynthetic rate, in terms of carbon fixation per leaf the benefits of larger leaves far outweighed the negative effects of reduced rates. Rates of aging of leaves and areas of leaves accounted for the major differences in carbon fixation per leaf among cultivars. There was no correlation between peak photosynthetic rates of leaf 3 and the flag leaf so that any screening for high rates could not be done on seedling leaves. In any event, this could be of doubtful benefit because yield per ear was unrelated to peak photosynthetic rates of the flag leaf. However, yield per ear was correlated with flag leaf area (P<0.05), rate of decline of flag leaf photosynthesis with age (P<0.001, inverse), and most closely with cumulative carbon production by the flag leaf during its life (P<0.001).

Effect of drought on ear and flag leaf photosynthesis of two wheat cultivars differing in drought resistance

2004 ◽  
Vol 42 (4) ◽  
pp. 559-565 ◽  
Author(s):  
T. Inoue ◽  
S. Inanaga ◽  
Y. Sugimoto ◽  
P. An ◽  
A. E. Eneji
Keyword(s):  
Drought Resistance ◽  
Flag Leaf ◽  
Wheat Cultivars ◽  
Leaf Photosynthesis

Gas exchange rates and nitrogen concentrations in two winter wheat cultivars during the grain-filling period

1980 ◽  
Vol 58 (19) ◽  
pp. 2110-2116 ◽  
Author(s):  
W. N. Migus ◽  
L. A. Hunt
Keyword(s):  
Winter Wheat ◽  
Flag Leaf ◽  
Grain Filling ◽  
Wheat Cultivars ◽  
N Concentration ◽  
Nitrogen Concentrations ◽  
Winter Wheat Cultivars ◽  
N Treatment ◽  
Grain Filling Period ◽  
Rate Of Decline

CO2 exchange (CER) and transpiration (TR) rates of flag leaves, penultimate leaves, and the ear of two winter wheat cultivars (cv. Fredrick and cv. Bezostaya-1), were measured at intervals during the life of the flag leaf. These were grown at two levels of nitrogen (N), 105 and 210 mg L−1, supplied from the double ridge stage of apical development. Nitrogen concentrations and dry weights of the flag and penultimate leaves, and of various other plant parts, were also measured.CER of main culm flag leaves of both cultivars declined more slowly from ear emergence to approximately 2.5 weeks postanthesis than either before or after this period. Similarly, the CER pattern of main culm penultimate leaves of Fredrick showed a plateau during this same period. By contrast, CER of the penultimate leaves of Bezostaya declined more uniformly overtime. CER of illuminated ears declined steadily from anthesis, whereas CER in the dark decreased to a maximum negative value approximately 2 weeks postanthesis. Nitrogen treatment had little effect on these CER patterns, with the exception of Bezostaya penultimate leaves, in which the rate of decline was slower for the higher N treatment.Nitrogen concentrations of the flag and penultimate leaves, and in the nongrain ear component, decreased steadily during the grain-filling period for both cultivars and N treatments. Leaf N concentration also decreased during the preanthesis period in Fredrick at both N treatments, and in Bezostaya at the lower N treatment. The time – course of N concentration in the leaves was not closely mirrored by CER, indicating that factors other than the N concentration of the leaves were important in determining the pattern of CER.TR of the flag and penultimate leaves declined from full flag leaf expansion until anthesis and then rose during a 2- to 2.5-week-postanthesis period for both cultivars and N treatments, with the exception of Bezostaya at the lower N treatment. The increase in TR during the filling period suggests that the reduced rate of decline in CER at that time may have resulted, at least partly, because a reduction in gas phase resistance offset an increase in residual resistance.

Effects of foliar-applied sulphur and nitrogen on grain growth, grain sulphur and nitrogen concentrations and yield of winter wheat

1995 ◽  
Vol 125 (3) ◽  
pp. 331-339 ◽  
Author(s):  
M. W. Griffiths ◽  
P. S. Kettlewell ◽  
T. J. Hocking
Keyword(s):  
Winter Wheat ◽  
Grain Growth ◽  
Soil Analysis ◽  
Flag Leaf ◽  
Wheat Cultivars ◽  
Leaf Emergence ◽  
S Deficiency ◽  
Phytotoxic Effect ◽  
Nitrogen Concentrations ◽  
Winter Wheat Cultivars

SUMMARYElemental sulphur (32 kg S/ha) and urea (30 kg N/ha) were applied to the foliage of different winter wheat cultivars, halfat flag leaf emergence and halfat ear emergence, in factorial experiments in 1986, 1987 and 1988. There were no clear visual symptoms of S deficiency, but there was evidence from soil analysis, grain S concentration and grain N:S ratio that the crops were marginally deficient in sulphur. Disease severity was generally negligible. Leaf senescence at the end of grain growth was delayed by sulphur in two of the three years, both with and without urea in 1987, but only with urea in 1988. Sulphur, both alone and mixed with urea, increased grain S concentration from early grain growth in 1986 and 1987, but not until the end of grain growth in 1988. Urea alone reduced yield in 1986 and 1987, but mixing S with the urea compensated for this phytotoxic effect. Yield was not significantly increased by S when compared with plots receiving neither urea nor S.

Leaf development in relation to infection by Stagonospora nodorum and Septoria tritici in wheat

1996 ◽  
Vol 47 (7) ◽  
pp. 1169
Author(s):  
BA Peters ◽  
R Loughman ◽  
Pdi Prinzio ◽  
Prinzio P Di
Keyword(s):  
Leaf Development ◽  
Flag Leaf ◽  
Sowing Date ◽  
Thermal Time ◽  
Septoria Tritici ◽  
Stagonospora Nodorum ◽  
Wheat Cultivars ◽  
Leaf Production ◽  
Leaf Emergence ◽  
Sowing Dates

Disease and phenology were compared in 2 wheat cultivars (Aroona and Spear) differing in disease resistance and maturity, at early (April-May) to late (June) sowing dates in 1991 and 1992. The cultivars had similar rates of leaf development but the longer season cultivar Spear averaged up to one leaf more on the main stem than the midseason cultivar Aroona, depending on sowing date. The extra leaf production which delayed flag leaf emergence on Spear compared to Aroona at early sowings was associated with lower disease levels in 1991. The occurrence of leaf rust may have diminished this advantage in 1992. Resistance to Septoria tritici in Aroona did not affect disease progress compared to Spear. A comparison of disease over a segment of accumulated thermal time revealed that in 1991, under average seasonal conditions, the earliest sowing experienced the most disease. In 1992, above average late spring rainfall occurred and time of sowing had little influence on disease over the same segment of thermal time. We conclude that a cultivar appropriate for early sowing on the south coast should exhibit increasing leaf production in response to early sowing. This can result in a reduction of disease severity on the upper leaves through disease escape.

Effect of leaf spotting diseases on grain yield and seed traits of wheat in southern Saskatchewan

2002 ◽  
Vol 82 (3) ◽  
pp. 507-512 ◽  
Author(s):  
H. Wang ◽  
M. R. Fernandez ◽  
F. R. Clarke ◽  
R. M. DePauw ◽  
J. M. Clarke
Keyword(s):  
Grain Yield ◽  
Protein Concentration ◽  
Flag Leaf ◽  
Kernel Weight ◽  
Test Weight ◽  
Grain Protein ◽  
Seed Traits ◽  
Grain Protein Concentration ◽  
Leaf Emergence ◽  
Weight Test

Although leaf spotting diseases have been reported to have a negative effect on grain yield and seed characteristics of wheat (Triticum spp.), the magnitude of such effects on wheat grown on dryland in southern Saskatchewan is not known. A fungicide experiment was conducted at Swift Current (Brown soil) and Indian Head (Black soil) from 1997 to 1999 to determine the effect of leaf spotting diseases on yield and seed traits of wheat. Two fungicides, Folicur 3.6F and Bravo 500, were applied at different growth stages on three common wheat (Triticum aestivum L.) and three durum wheat (T. turgidum L. var durum) genotypes. Fungicide treatments generally did not affect yield, kernel weight, test weight or grain protein concentration, and these effects were relatively consistent among genotypes. Folicur applied at head emergence in 1997 and at flag leaf emergence and/or head emergence in 1998 increased yield at Indian Head (P < 0.05). Fungicides applied at and before flag leaf emergence tended to increase kernel weight. Grain protein concentration increased only in treatments of Bravo applications at Indian Head in 1998. These results suggested that under the dryland environment and management in southern Saskatchewan leaf spotting diseases generally have a small effect on yield, kernel weight, test weight and protein concentration. Key words: Wheat, leaf spotting diseases, fungicide, yield

scholarly journals Diurnal Variations in Physiological Characteristics, Photoassimilates, and Total Ascorbate in Early and Late Sown Indian Wheat Cultivars under Exposure to Elevated Ozone

Atmosphere ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1568
Author(s):  
Durgesh Singh Yadav ◽  
Bhavna Jaiswal ◽  
Shashi Bhushan Agrawal ◽  
Madhoolika Agrawal
Keyword(s):  
Ascorbic Acid ◽  
Ascorbic Acid Content ◽  
Triticum Aestivum L ◽  
Diurnal Changes ◽  
Wheat Cultivars ◽  
Negative Effects ◽  
Breeding Programs ◽  
Elevated O3 ◽  
Elevated Ozone ◽  
Selection Of

Rising tropospheric ozone (O3) in the atmosphere is detrimental to crop’s productivity and is one of the reasons for a warmer climate. The present study describes diurnal changes in gaseous exchange, chlorophyll fluorescence, ascorbic acid, and photoassimilate parameters in flag leaves of four Indian wheat (Triticum aestivum L.) cultivars (two early sown and two late sown cultivars) under ambient and elevated O3 treatments, using the open-top chambers (OTCs). Results showed that the diurnal pattern of photosynthetic rate (Ps), sucrose, and ascorbic acid content varied according to changes in photosynthetically active radiation (PAR) and O3 concentrations during the daytime and were maximum between 10:00 to 12:00. The present study suggested that elevated O3 caused more negative effects on photosystem II in early sown compared to late sown cultivars. The greater loss of photosynthesis led to lower production of photoassimilates in early sown cultivars, which utilized more assimilates in ascorbic acid formation for detoxification of ROS formed due to elevated O3. This work will also help to identify the robustness of physiological machinery in different wheat cultivars under elevated levels of O3, and may be used for selection of suitable cultivars during future breeding programs.

scholarly journals DEVELOPMENTAL CELL DEATH IN WHEAT FLAG LEAF TIPS IN TWO WHEAT CULTIVARS

2019 ◽  
Vol 26 ◽  
pp. 109-116
Author(s):  
Kipkios TUBEI ◽  
Lucas CHURCH ◽  
Tim XING
Keyword(s):  
Cell Death ◽  
Flag Leaf ◽  
Wheat Cultivars ◽  
Developmental Cell Death

Thermal Adaptation of Pennisetum: Leaf Photosynthesis and Photosynthate Translocation

1977 ◽  
Vol 4 (5) ◽  
pp. 763 ◽  
Author(s):  
CJ Pearson ◽  
GA Derrick
Keyword(s):  
Low Temperature ◽  
Growth Rates ◽  
Thermal Adaptation ◽  
Leaf Photosynthesis ◽  
Photosynthetic Rates ◽  
Photosynthate Translocation

Leaf photosynthetic rates, loss of photosynthate 14C, sucrose concentrations and invertase activities were measured in three genotypes of Pennisetum growing at daylnight temperatures that ranged from 18/13 to 33/28°C. Leaves at low temperature had low photosynthetic rates, exported 14C more slowly, retained a higher proportion of photosynthate 14C, had higher sucrose concentrations and aged (physiologically) more slowly than did leaves growing at higher temperatures. The genotype that retained most photosynthate in the source leaves was the most cold-intolerant whereas there was no correlation between photosynthetic rates and previously observed growth rates.

scholarly journals Improved Prediction of Leaf Emergence for Efficacious Crop Protection: Assessing Field Variability in Phyllotherms for Upper Leaves in Winter Wheat and Winter Barley

Agronomy ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1825
Author(s):  
Moussa El Jarroudi ◽  
Louis Kouadio ◽  
Jürgen Junk ◽  
Clive H. Bock
Keyword(s):  
Winter Wheat ◽  
Disease Risk ◽  
Flag Leaf ◽  
Crop Protection ◽  
Absolute Error ◽  
Winter Barley ◽  
Prediction Errors ◽  
Fungicide Application ◽  
Leaf Emergence ◽  
Environmentally Sound

The choice of the phyllotherm value for predicting leaf emergence under field conditions is pivotal to the success of fungicide-based disease risk management in temperate cereals. In this study, we investigated phyllotherm variability for predicting the emergence of the three uppermost leaves (i.e., three last leaves to emerge) in winter wheat and winter barley fields. Data from four sites representative of wheat and barley growing regions in Luxembourg were used within the PROCULTURE model to predict the emergence of F-2, F-1 and F (F being the flag leaf) during the 2014–2019 cropping seasons. The phyllotherms tested ranged between 100 °Cd and 160 °Cd, in 15 °Cd steps, including the current default value of 130 °Cd. The comparisons between the observed and predicted emerged leaf area were qualitatively evaluated using the mean absolute error (MAE), the root mean square error (RMSE) and Willmott’s index (WI). A phyllotherm of 100 °Cd accurately and reliably predicted the emergence of all three upper leaves under the various environmental conditions and crop cultivars of winter wheat and winter barley over the study period. MAE and RMSE were generally <5% and the WI values were most often ≥0.90 for F-1 and F. For phyllotherm values ≥115 °Cd, the prediction errors generally increased for F-1 and F, with MAE and RMSE exceeding 20% in most cases. F-2 agreement between observed and predicted values was generally similar when using 100 °Cd or 115 °Cd. These results tie in valuable, complementary information regarding the variability of phyllotherms within leaf layers in winter wheat and winter barley in Luxembourg. Accurate and reliable leaf emergence prediction from F-2 to F allows for timely fungicide application, which ensures lasting protection against infections by foliar fungal disease pathogens. Hence, understanding phyllotherms can help ensure timely, environmentally sound, and efficacious fungicide application while increasing the likelihood of improved yields of winter wheat and winter barley.

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