Effects of a period of high temperature during grain filling on the grain growth characteristics and malting quality of three Australian malting barleys

1998 ◽  
Vol 49 (8) ◽  
pp. 1287 ◽  
Author(s):  
M. A. B. Wallwork ◽  
S. J. Logue ◽  
L. C. MacLeod ◽  
C. F. Jenner
Keyword(s):  
High Temperature ◽  
High Temperatures ◽  
Dry Matter ◽  
Protein Modification ◽  
Water Extract ◽  
Grain Filling ◽  
Hot Water ◽  
Grain Weight ◽  
Starch Accumulation ◽  
Heat Treated

Short periods of high temperatures (up to 35°C) during mid grain filling appear to reduce yield and quality in barley. Plants of 3 malting barley varieties, Schooner, Arapiles, and Sloop (a new South Australian malting variety), were grown under constant environment conditions from germination to maturity and exposed to 5 days of high temperatures (up to 35°C) during mid grain filling. Schooner and Sloop showed similar patterns of accumulation of dry matter under control conditions (21°C/16°C, day/night temperature) and in response to high temperatures. In all varieties, the reduction in starch accumulation represented the most significant detrimental effect of high temperature and made the greatest contribution to the reduction in final grain weight. The reduction in absolute grain nitrogen (N) in heat-treated Arapiles grains represents a potentially important response under high temperature conditions. In this study, water loss did not have a decisive role in the termination of grain filling. Continued accumulation of endosperm dry matter at low moisture levels suggested that water distribution and/or components of water potential may be more important than overall water content in the cessation of grain filling. Final grain composition depended not only on the amount of endosperm storage component present in the grain but also on the contribution of the non-endosperm components (including the embryo and husk) to final grain dry weight. In some cases, changes in the contribution made by the non-endosperm components of the grain to final grain weight masked important high temperature effects on key endosperm storage components. Hot water extract (HWE) values were similar within treatments and ranged from 73% to 78%. High temperature exposure reduced HWE for all varieties. Malt b-glucan was lower in heat-treated grains than in control grains. Despite relatively high malt protein levels in all varieties, higher free amino N levels in heat-treated grains indicated a higher protein modification than in control grains.

Starch Synthesis in the Kernel of Wheat Under High Temperature Conditions

1994 ◽  
Vol 21 (6) ◽  
pp. 791 ◽  
Author(s):  
CF Jenner
Keyword(s):  
High Temperature ◽  
Dry Matter ◽  
Starch Content ◽  
Starch Synthesis ◽  
Temperature Response ◽  
Grain Filling ◽  
Soluble Starch ◽  
Grain Weight ◽  
Temperature Range ◽  
Temperature Responses

As temperature rises above 18-22�C, the observed decrease in the duration of deposition of dry matter in the kernel is not accompanied by a compensating increase in the rate of grain filling with the result that grain weight (and yield) is diminished at high temperature. Reduced starch content accounts for most of the reduction in grain dry matter at high temperature. Responses to temperature in the low temperature range, 20-30�C (the LTR), could possibly be ascribed to the temperature response characteristics of the reaction catalysed by soluble starch synthase (SSS), the enzyme synthesising starch. However, the rate of cell enlargement and the rate of accumulation of nitrogen in the grain also do not increase much as temperature rises, so other explanations are conceivable for the temperature responses in the LTR. Variation amongst cultivars of wheat in tolerance of high temperature is evident in the LTR. At temperatures above 30�C (in the high temperature range (HTR) between 30 and 40�C), even for short periods, the rate of starch deposition is slower than that observed at lower temperatures, an effect which is carried over after transfer from high to lower temperatures. This response is attributable to a reduction in the activity, possibly due to thermal denaturation, of SSS. Several forms of SSS are found in cereal endosperm, and some forms may be more tolerant of high temperature than others. Loss of enzyme activity at high temperature is swift, but is partly restored some time after transfer from hot to cool conditions. There appear to be two distinct mechanisms of response to elevated temperature, both resulting in a reduced grain weight through reduced starch deposition, but one of them is important only in the range of temperature above 30�C.

Grain growth and malting quality of barley. 1. Effects of heat stress and moderately high temperature

1997 ◽  
Vol 48 (5) ◽  
pp. 615 ◽  
Author(s):  
Roxana Savin ◽  
Peter J. Stone ◽  
Marc E. Nicolas ◽  
Ian F. Wardlaw
Keyword(s):  
Heat Stress ◽  
High Temperature ◽  
Grain Growth ◽  
High Temperatures ◽  
Grain Filling ◽  
Grain Weight ◽  
Malting Quality ◽  
Very High ◽  
Moderately High Temperature

In this study, controlled-environment conditions were used to compare the effects of moderately high and very high temperatures during grain filling on grain growth and malting quality of barley. Heat stress applied from 15 to 20 days after anthesis (DAA) reduced grain weight by about 35%, whereas longer periods (15–20 days) of moderately high temperature applied from 20 DAA to maturity reduced grain weight by about 6%. Both heat stress and moderately high temperature resulted in reduced grain weight through a reduction in the duration of grain filling. Grain composition was altered by both moderately high and very high temperatures, although the changes were larger under very high temperatures. In general, there was a decrease in starch content, resulting from the reduction in both volume and number of A- and B-type starch granules. Nitrogen concentration was significantly increased only in the 30/25°C treatments, and changes in diastatic power were only minor. There was a reduction in β-glucan content, together with an increase in β-glucan degradation. However, malt extract was not significantly affected by these stresses.

Effect of high temperature during grain filling on starch synthesis in the developing barley grain

1998 ◽  
Vol 25 (2) ◽  
pp. 173 ◽  
Author(s):  
M. A. B. Wallwork ◽  
S. J. Logue ◽  
L. C. MacLeod ◽  
C. F. Jenner
Keyword(s):  
Catalytic Activity ◽  
High Temperature ◽  
High Temperatures ◽  
Starch Synthesis ◽  
Grain Filling ◽  
Soluble Starch ◽  
Barley Grain ◽  
Starch Synthase ◽  
Heat Treated ◽  
C 30

Plants of malting barley variety Schooner were exposed to 5 days of high temperatures (up to 35°C) during mid grain filling under controlled environment conditions. Grains from heat treated plants accumulated c. 30% less starch than grains from control plants (21/16°C; 14 h day). Reduced starch deposition was not limited by assimilate levels in heat treated grains, but high temperature reduced the conversion of sucrose to starch. The reduction in starch synthesis appeared to result from the effects of diminished catalytic activity of a number of enzymes in the committed pathway of starch synthesis, and/or delayed recovery of enzyme activity in the cooler recovery conditions. Reductions of 11–75% in the activity of the enzymes under investigation followed high temperature exposure. In addition, ADPglucose pyrophosphorylase, branching enzyme and granule bound starch synthase showed increased activity during exposure to moderate temperatures (28–32°C), but reduced activity at high temperatures, while soluble starch synthase showed an immediate loss of activity, even at moderate temperatures. Sucrose synthase and UDPglucose pyrophosphorylase showed the greatest reduction in catalytic activity after plants were returned to cooler conditions. Individual enzymes showed variation in the level of recovery under the cooler temperature conditions which followed the heating period.

Effects of Short Periods of Drought and High Temperature on Grain Growth and Starch Accumulation of Two Malting Barley Cultivars

1996 ◽  
Vol 23 (2) ◽  
pp. 201 ◽  
Author(s):  
R Savin ◽  
ME Nicolas
Keyword(s):  
Heat Stress ◽  
High Temperature ◽  
Grain Growth ◽  
Grain Filling ◽  
Grain Weight ◽  
Maximum Temperature ◽  
Starch Accumulation ◽  
Nitrogen Accumulation ◽  
Barley Cultivars ◽  
High Temperature Maximum

Short periods (3-5 days) of high maximum temperature (>35�C), often accompanied by drought, commonly occur during grain filling of cereals. Short periods of high temperature have been shown to reduce grain weight and baking quality in wheat, but little is known about their effects on barley. Consequently, we examined the effects of high temperature and drought, alone or combined, on grain growth for two barley cultivars, Schooner and Franklin. Treatments started 15 days after anthesis and consisted of the factorial combination of three temperatures and three water regimes. The high temperature (maximum 40�C for 6 h day-1) and drought treatments were maintained for 5 or 10 days. Drought reduced individual grain weight much more (ca 20%) than high temperature (ca 5%) for both cultivars. Franklin appeared to be more sensitive to heat stress than Schooner. The reduction in individual grain weight was greatest when both stresses were combimed (ca 30%). The reduction in mature grain weight under high temperature was due to a reduction in duration of grain growth for Schooner and to a reduction in both rate and duration of grain growth for Franklin (8-12%). The reduction in duration of grain growth was the most important cause of reduced grain weight at maturity under drought alone (12-25%) or combined with high temperature (25-33%). Nitrogen content per grain was quite high and similar for all treatments, and nitrogen percentage increased when stress was severe enough to reduce starch accumulation, confirming that starch accumulation is more sensitive to post- anthesis stress than nitrogen accumulation. We conclude that drought, particularly when combined with high temperature, is more likely than heat stress to cause large reductions in grain weight of barley under field conditions.

Grain weight and malting quality in barley as affected by brief periods of increased spike temperature under field conditions

2002 ◽  
Vol 53 (11) ◽  
pp. 1219 ◽  
Author(s):  
Valeria S. Passarella ◽  
Roxana Savin ◽  
Gustavo A. Slafer
Keyword(s):  
Heat Stress ◽  
High Temperature ◽  
High Temperatures ◽  
Grain Filling ◽  
Grain Weight ◽  
Malting Quality ◽  
Malt Extract ◽  
Yield And Quality ◽  
Grain Nitrogen ◽  
Nitrogen Percentage

High temperature is usually one of the most important stresses during grain filling affecting both yield and quality in barley crops. In the present study, an attempt was made to assess in the field the effects of short periods of high temperature, using transparent boxes covering only the spikes, with thermostatically controlled electric resistance for increasing the temperature. Treatments consisted of 2 malting cultivars and 5 heat treatments of high temperatures (8�C above the environmental temperature for 6 h/day for 5 consecutive days) over different periods during grain filling. Final grain weight was reduced by 2–14%, depending on the timing of heat stress and the genotype. There was a significant increase in grain nitrogen percentage in both cultivars, and grain β-glucans decreased with high temperatures in Logan and were unchanged in Beka. The resulting malt extract was reduced with exposure to high temperatures, depending on the cultivar, implying that even mild heat stress may change malting performance.

Effect of heat treatment and heat treatment in combination with lignosulfonate on in situ rumen degradability of canola cake crude protein, lysine, and methionine

2020 ◽  
Vol 100 (1) ◽  
pp. 165-174 ◽  
Author(s):  
Piotr Micek ◽  
Katarzyna Słota ◽  
Paweł Górka
Keyword(s):  
Heat Treatment ◽  
High Temperature ◽  
Crude Protein ◽  
Dry Matter ◽  
Increased Temperature ◽  
Heat Treated ◽  
Cold Pressed ◽  
Temperature Heating ◽  
High Temperature Heating

The aim of this study was to determine the effect of heat treatment alone or in combination with the addition of lignosulfonate (LSO3) on canola cake protein, lysine, and methionine degradation in the rumen. Cold-pressed canola cake was left untreated, heated at 90, 110, 130, or 150 °C, or processed with 5% of LSO3 (in dry matter) and then heated. Effective rumen degradability of crude protein (CP), lysine, and methionine was less for treated than untreated canola cake (P < 0.05) and decreased with increased temperature of heating, but particularly when canola cake was heated at 150 °C (quadratic, P < 0.01). In general, effective rumen degradability of CP, lysine, and methionine was less for canola cake heated at 130 °C in combination with LSO3 compared with canola cake heat treated only (quadratic × LSO3 interaction, P ≤ 0.07). Results of this study indicate that high temperature heating (130 °C or greater for 60 min) may be necessary to protect canola cake protein from degradation in the rumen, and the combination of heat treatment and LSO3 may be more effective in protecting canola cake protein, lysine, and methionine from degradation in the rumen than the use of heat treatment only.

Breeding effects on sensitivity of barley grain weight and quality to events of high temperature during grain filling

Euphytica ◽  
2005 ◽  
Vol 141 (1-2) ◽  
pp. 41-48 ◽  
Author(s):  
Valeria S. Passarella ◽  
Roxana Savin ◽  
Gustavo A. Slafer
Keyword(s):  
High Temperature ◽  
Grain Filling ◽  
Barley Grain ◽  
Grain Weight

Effects of Exposure of Wheat Ears to High Temperature on Dry Matter Accumulation and Carbohydrate Metabolism in the Grain of Two Cultivars. I. Immediate Responses

1991 ◽  
Vol 18 (2) ◽  
pp. 165 ◽  
Author(s):  
CF Jenner
Keyword(s):  
High Temperature ◽  
Sucrose Synthase ◽  
Dry Matter ◽  
Starch Synthesis ◽  
Grain Filling ◽  
Mass Action ◽  
Dry Matter Accumulation ◽  
Partial Explanation ◽  
Calculated Mass ◽  
Percentage Basis

Ears of wheat were exposed for up to 7 days during the grain-filling stage to high temperature (35�C day/25�C night) and metabolic responses in the grain were compared to those in ears maintained at lower temperatures (21�C day/16�C night). Two cultivars of wheat known to differ in their post-anthesis tolerance of high temperature were compared. Raising the temperature resulted in a small increase in the rate of dry matter accumulation: both cultivars responded similarly. Sucrose content of the endosperm was either not affected or increased by raising the temperature. Raising the temperature had differential effects on glucose and fructose content: fructose was substantially reduced while glucose was either unaffected or slightly increased. After raising the temperature the concentrations of all three hexose phosphates measured, glucose-6-phosphate (G-6-P), glucose-1-phosphate (G-1-P) and fructose-6-phosphate (F-6-P), were reduced similarly on a percentage basis and to about the same extent as fructose. The concentration of the sugar nucleotide (UDP-glucose) resulting from the breakdown of sucrose by sucrose synthase was also reduced at high temperature. Judging from calculated mass-action ratios, all three catalytic steps involved in the interconversion of the metabolites mentioned above were close to equilibrium, and only one mass action ratio (for sucrose synthase) was affected by heating: it was doubled. Although temperature clearly resulted in changes in the reaction catalysed by sucrose synthase, it was not clear how temperature had acted. Concentration of the precursor for starch synthesis (ADP-glucose) was slightly lower in both cultivars at the higher temperature. Taken together the responses could provide at least a partial explanation for the smallness of the increase in starch deposition with increase in temperature, but do not explain the different responses of these two cultivars to high temperature.

Grain-Filling in Wheat Plants Shaded for Brief Periods After Anthesis

1979 ◽  
Vol 6 (6) ◽  
pp. 629 ◽  
Author(s):  
CF Jenner
Keyword(s):  
Dry Matter ◽  
Grain Filling ◽  
Grain Weight ◽  
Controlled Environment ◽  
Grain Development ◽  
Early Stages

Plants of wheat (grown in a controlled environment) were subjected to brief (5-10 days) periods of shading just after the ears showed the first signs of anthesis, and afterwards were grown to maturity in full illumination. Shading resulted in smaller grains, slower rates of accumulation of dry matter in the grains, and lower final grain weights. Shading cut down contemporaneously the provision of sucrose to the developing grain but, soon after return to full illumination, the supply of sucrose was restored to levels observed in ears that had not been shaded. Moreover, the estimated concentrations of sucrose in the endosperm of grains that accumulated less dry matter as a result of shading were higher than in endosperm filling on the unshaded plants. Although shading resulted in lighter grains, the grains contained just as much protein as the unshaded ones. Trimming the ears (by removing some spikelets) of shaded plants did not influence grain weight. These responses to shading are taken as evidence for the existence of a mechanism operating during the early stages of grain development, before grain-filling begins, which can influence the capacity of the endosperm to accumulate starch. Capacity to accumulate protein is evidently not subject to the same kind of control.

Sign in / Sign up

Export Citation Format

Share Document