Effects of Temperature on the Conversion of Sucrose to Starch in the Developing Wheat Endosperm

1986 ◽  
Vol 13 (5) ◽  
pp. 605 ◽  
Author(s):  
SS Bhullar ◽  
CF Jenner
Keyword(s):  
Elevated Temperature ◽  
Starch Synthesis ◽  
Grain Filling ◽  
Residual Effects ◽  
Effect Of Temperature ◽  
Soluble Carbohydrate ◽  
Wheat Endosperm ◽  
14Co2 Production ◽  
Response To Temperature

Elevated temperature during grain filling resulted in reduced single grain weight due largely to an effect of temperature on the accumulation of starch in the endosperm. Wheat endosperm was cultured in vitro on solutions of [14C]sucrose and the responses to variation in temperature within the range 15-35°C were evaluated in terms of the absorption of radioactive sugar, the evolution of 14CO2, and the incorporation of radioactivity into starch. At 35°C the level of 14C in the intracellular pool of soluble carbohydrate was higher than it was at 30°C, and the average Q,10 for 14CO2 production was 2.1. Incorporation of 14C into starch was greater at 30°C than at 25°C, but at 35°C only half as much [14C]starch was produced compared with that at 30°C. Residual effects of exposure of ears to brief episodes of elevated temperature were investigated by culturing endosperm isolated from such ears on [14C]sucrose at a standard temperature (25°C). Two days of exposure resulted in greater amounts of [14C]starch produced, due to accelerated starch depo- sition, but longer periods (4-6 days) at elevated temperature resulted in substantial reductions in [14C]starch deposition. Exposure to elevated temperature also hastened the onset of chlorophyll degradation in the pericarp of the grain. Two types of response to temperature appear to be involved: a comparatively low temperature optimum for starch synthesis, and an irreversible reduction in the capacity of the endosperm to convert sucrose to starch resulting from exposure of the ears, or the grains themselves, to elevated temperature.

Heat Stress During Grain Filling in Maize: Effects on Carbohydrate Storage and Metabolism

1994 ◽  
Vol 21 (6) ◽  
pp. 829 ◽  
Author(s):  
GW Singletary ◽  
R Banisadr ◽  
PL Keeling
Keyword(s):  
Heat Stress ◽  
Seed Size ◽  
Starch Synthesis ◽  
Dry Weight ◽  
Grain Filling ◽  
Soluble Starch ◽  
Effect Of Temperature ◽  
Starch Accumulation ◽  
Maize Kernels

Heat stress during maize seed development can interfere with endosperm starch biosynthesis and reduce seed size, an important component of yield. Our objectives were to evaluate the direct influence of temperature during grain filling on kernel growth, carbohydrate accumulation, and corresponding endosperm metabolism. Kernels of maize were grown in vitro at 25�C until 15 or 16 days after pollination and then subjected to various temperatures for the remainder of their development. Mature kernel dry weight declined 45% in a linear fashion between 22 and 36�C. The rate of starch accumulation reached a maximum at approximately 32�C, and when measured at frequent intervals, declined only slightly with further temperature increase to 35�C. Reduced seed size resulted from an abbreviated duration of starch-related metabolism, which did not appear to be limited by endogenous sugars. Instead, a survey of 12 enzymes of sugar and starch metabolism indicated that ADP glucose pyrophosphorylase and soluble starch synthase were unique in displaying developmental peaks of activity which were compressed both in amount and time, similar to the effect of temperature on starch accumulation. We conclude that decreased starch synthesis in heat-stressed maize kernels results from a premature decline in the activity of these enzymes.

Effects of high temperature on grain growth and on the metabolites and enzymes in the starch-synthesis pathway in the grains of two wheat cultivars differing in their responses to temperature

2003 ◽  
Vol 30 (3) ◽  
pp. 291 ◽  
Author(s):  
Morteza Zahedi ◽  
Rajinder Sharma ◽  
Colin F. Jenner
Keyword(s):  
High Temperature ◽  
Starch Synthesis ◽  
Grain Filling ◽  
Triticum Aestivum L ◽  
Soluble Starch ◽  
Starch Synthase ◽  
Effect Of Temperature ◽  
The Difference

The effects of a sustained period of moderately high temperature were evaluated on the availability of substrate and the activity of starch synthase (ADP-glucose: 1,4-α-D-glucan 4-α-D-glucosyltransferase, EC 2.4.1.21) in the developing grains of two wheat Triticum aestivum L. cultivars differing in their tolerance to high temperature. Final grain weight was reduced by 33% in the least sensitive (cv. Kavko) and by 40% in the most sensitive (cv. Lyallpur) cultivar as post-anthesis temperature was raised from 20/15°C (day/night) to 30/25°C. The difference in the response of the two cultivars was mainly due to changes in the rate of grain filling at high temperature. The response of the rate of grain filling at high temperature, and the differential effects on the two cultivars, did not seem to be explained by an effect of temperature on the supply of assimilate (sucrose) or on the availability of the substrate for starch synthesis (ADP-glucose) in the grains. In vitro, but not in vivo, the differential responses of the efficiency (Vmax/Km) of soluble starch synthase in the two cultivars to an increase in temperature were associated with differences in the temperature sensitivity of grain filling. In vivo, the most remarkable difference between the two varieties was in the absolute values of the efficiency of soluble starch synthase, with the most tolerant cultivar having the highest efficiency.

Effects of a Brief Episode of Elevated Temperature on Grain Filling in Wheat Ears Cultured on Solutions of Sucrose

1986 ◽  
Vol 13 (5) ◽  
pp. 617 ◽  
Author(s):  
SS Bhullar ◽  
CF Jenner
Keyword(s):  
Elevated Temperature ◽  
Grain Filling ◽  
Grain Weight ◽  
Residual Effects ◽  
Low Concentration ◽  
Intact Plants

The hypothesis that reduced grain weight resulting from elevated temperature is the result of a reduction in the supply of assimilates to the grain or lessened availability of sucrose within the endosperm for grain filling has been investigated. Detached ears of wheat were cultured on solutions of sucrose varying in concentration from a level which supports normal rates of grain filling to one above and one below that level. Contrary to expectation, at the low concentration of sucrose the rate of grain filling in detached ears increased more at elevated temperature than it did in ears supplied with higher concentrations of sucrose, or compared with ears developing on intact plants. In other experiments ears were detached and, after a brief exposure to elevated temperature, were cultured on solutions of sucrose. The residual effects of warming, expressed as slower grain filling and lower mature grain weight, were less pronounced at low than at higher concentrations of sucrose. This result also is not in accordance with the hypothesis.

scholarly journals Temperature, Leaf Wetness, and Isolate Effects on Infection of Minneola Tangelo Leaves by Alternaria sp.

Plant Disease ◽  
1999 ◽  
Vol 83 (5) ◽  
pp. 429-433 ◽  
Author(s):  
Y. Canihos ◽  
T. L. Peever ◽  
L. W. Timmer
Keyword(s):  
Polynomial Equation ◽  
Brown Spot ◽  
Effect Of Temperature ◽  
Leaf Wetness ◽  
Significant Difference ◽  
Alternaria Brown Spot ◽  
Detached Leaves ◽  
Alternaria Sp ◽  
Response To Temperature

Alternaria brown spot causes necrotic lesions on immature leaves, twigs, and fruit of tangerines and their hybrids, reducing yield and fruit quality. The effect of temperature, leaf wetness, and isolate was evaluated in an in vitro system using immature detached leaves of Minneola tangelo Infection was greatest at 27°C, decreased gradually as the temperature declined to 24, 20, and 17°C, and dropped sharply at 32°C. Levels of infection were low at 4 and 8 h of leaf wetness and continued to increase with longer wetting periods up to 36 h. A polynomial equation was developed that provided a good fit for the data (adjusted R2 = 0.93). Isolates differed in aggressiveness, but there was no significant difference among isolates in their response to temperature and leaf wetness duration.

Effect of spraytopping applications of paraquat and glyphosate on the nutritive value and regeneration of vulpia (Vulpia bromoides (L.) S.F. Gray)

1991 ◽  
Vol 42 (8) ◽  
pp. 1405 ◽  
Author(s):  
AR Leys ◽  
BR Cullis ◽  
B Plater
Keyword(s):  
Nutritive Value ◽  
Grain Filling ◽  
Water Soluble ◽  
Soluble Carbohydrate ◽  
Wagga Wagga ◽  
Time Of Application ◽  
Water Soluble Carbohydrate ◽  
Subsequent Regeneration ◽  
Earlier Application

The effects of paraquat and glyphosate on the nutritive value of dry residues of vulpia [Vulpia bromoides (L.) S. F. Gray], and its subsequent regeneration the following year were examined at Wagga Wagga during the spring, summer and winter of 1986/87 and 1987/88. Paraquat (100 and 200 g a.i./ha) and glyphosate (135 and 270 g a.i./ha) were applied as spraytopping treatments at heading, anthesis and early grain filling stages of vulpia. For both herbicides, time of application was critical to the level of regeneration obtained. Glyphosate gave 84 and 83% control when applied at heading and anthesis respectively, delaying application until early grain filling reduced the level of vulpia control to 28%. Paraquat gave 81% control when applied at anthesis, while delaying application until early grain filling, or earlier application at heading, gave 59% control. Crude protein (CP) and water-soluble carbohydrate (WSC) concentrations, and in vitro organic matter digestibilities (OMD) were measured in vulpia residues collected for 16 weeks after herbicide application. Paraquat increased CP levels most when applied at heading (from 4-8 to 7.2% in 1986, and from 4.9 to 6.5% in 1987). Glyphosate increased CP levels most when applied at heading in 1986 (from 4.8 to 5.4%), but at anthesis in 1987 (from 4.9 to 6.5%). Glyphosate increased WSC most when applied at heading (from 5.7 to 10.6% in 1986, and from 3.5 to 6.3% in 19871, while paraquat reduced WSC in both years. Application of glyphosate at heading was the only treatment to increase OMD (from 50.5 to 54.7%).

The effect of water stress on grain filling processes in wheat

2001 ◽  
Vol 136 (3) ◽  
pp. 257-269 ◽  
Author(s):  
A. AHMADI ◽  
D. A. BAKER
Keyword(s):  
Water Stress ◽  
Water Status ◽  
Starch Synthesis ◽  
Grain Filling ◽  
Sucrose Uptake ◽  
Effect Of Water ◽  
Carry Over ◽  
Synthetic Capacity

The effect of water stress, commencing from the late cell division period, on in vivo grain growth was studied in relation to grain sucrose, water status and in vitro starch synthesis. Detached ear experiments were conducted to assess the effect of sink dehydration on grain filling processes under non-limiting source conditions. Water stress caused premature grain desiccation and resulted in a marked decline in grain sucrose and reduced grain weight. Both sucrose uptake and conversion to starch in vitro were increased by mild water stress (solute potential (Ψs)−0·8 MPa). However, a decline in Ψs below this optimum resulted in reduced sucrose uptake and starch synthesis not attributable to a reduced supply of sucrose. Stressed grains which failed to accumulate dry matter in vivo showed significant starch synthesis when cultured in vitro. Grains from in situ and osmotically stressed plants showed a lower capacity for starch synthesis in vitro. The results indicate that grain filling processes under stress conditions are limited by (1) low substrate availability and low Ψs within the sink i.e. an unfavourable seed environment (non-lasting effect) and (2) reduced synthetic capacity of the sink (carry-over effect).

Effect of Temperature on Enzymes in the Pathway of Starch Biosynthesis in Developing Wheat and Maize Grain

1994 ◽  
Vol 21 (6) ◽  
pp. 807 ◽  
Author(s):  
PL Keeling ◽  
R Banisadr ◽  
L Barone ◽  
BP Wasserman ◽  
GW Singletary
Keyword(s):  
Elevated Temperature ◽  
Thermal Inactivation ◽  
Starch Synthesis ◽  
Soluble Starch ◽  
Effect Of Temperature ◽  
Branching Enzyme ◽  
Temperature Optimum ◽  
Significant Yield ◽  
Maize Grain ◽  
Lower Temperature

Soluble starch synthase (SSS) is shown to be a major site of control of flux through the pathway of starch synthesis in developing wheat and maize grain. Temperatures above 25�C adversely affect flux, and therefore, limit yield. This process is linked to SSS which is heat sensitive. Two apparently different properties of SSS can be identified which differ in the period required before full activity is restored after heat treatment. First, enzyme rate is adversely affected by elevated temperature, an effect which is reversible on returning to a lower temperature. The effect on enzyme rate was quantified using enzyme Q10 which was found to begin to be sub-optimal above 20�C. Second, with a prolonged period of exposu;e to elevated temperature there is a loss of enzyme activity which is not freely reversible which we have termed thermal inactivation. Although this occurs at temperatures in excess of 20�C in wheat, higher temperatures of more than 30�C are needed in maize SSS. Elevated temperature did not affect the inherent stability or Q10 characteristics of other enzymes in the pathway of starch synthesis except for branching enzyme which we believe has minimal flux-control strength. SSS thermal inactivation may not be a major problem in field conditions for developing maize grain, because temperatures rarely are high enough. However, we suggest that the effect on enzyme Q10 is more physiologically relevant, since maize SSS is operating sub-optimally as temperatures exceed 20�C. Calculations of the reductions in maize US corn-belt yield showed that significant yield improvement might be obtained by a 5�C shift in the temperature optimum. Thus selections for a more temperature tolerant form of maize SSS were conducted using enzyme Q10 as a selection tool. Of several hundred maize specimens screened, two were found to be significantly different. However, attempts to use backcross breeding to transfer this trait from the tropical donor to another line have not yet succeeded. Transgenic approaches to altering relations of starch deposition are now underway.

scholarly journals Response of elevated temperature on carbohydrate accumulation and grain yield in different wheat cultivars

2015 ◽  
Vol 40 (2) ◽  
pp. 205-215 ◽  
Author(s):  
Soyema Khatun ◽  
Jalal Uddin Ahmed
Keyword(s):  
Grain Size ◽  
Elevated Temperature ◽  
Grain Yield ◽  
Open Field ◽  
Soluble Sugar ◽  
Starch Synthesis ◽  
Grain Filling ◽  
Wheat Cultivars ◽  
Carbohydrate Accumulation ◽  
Grain Filling Duration

In order to study the response of terminal heat stress on carbohydrate accumulation and grain yield of three wheat cultivars namely BARI Gom 25, BARI Gom 26 and Pavon 76 were sown on 18 November, 2011 in experimental field of Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur in Bangladesh and two temperature regimes viz. normal (23°C in open field) and elevated (6 ± 1°C higher compare to open field mean air temperature in polythene chamber) were created. Elevated temperature shortened the grain filling duration by 5-day in BARI Gom 25 and BARI Gom 26 and 10-day in Pavon 76. Under elevated temperature condition grain starch synthesis was found to be stopped at 25 days after anthesis (DAA) in Pavon 76 which in BARI Gom 26 appeared 5-day later (30 DAA) in spite of higher level of soluble sugar in grain. Results indicate that early failure of conversion of sugar to starch rather than supply of soluble sugar under elevated temperature condition were responsible for shortening of grain filling duration and smaller grain size in all wheat cultivars. Smaller reduction of grain size and grain number along with smaller reduction of grain weight per main stem under elevated temperature condition finally contributed to sustain negligible loss of grain yield, biological yield and harvest index in BARI Gom 25 and BARI Gom 26 compare to Pavon 76.Bangladesh J. Agril. Res. 40(2): 205-215, June 2015

scholarly journals Variation of Wheat Cultivars in Their Response to Elevated Temperature on Starch and Dry Matter Accumulation in Grain

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Soyema Khatun ◽  
Jalal Uddin Ahmed ◽  
Tofazzal Hossain ◽  
M. Rafiqul Islam ◽  
Mohammed Mohi-Ud-Din
Keyword(s):  
Elevated Temperature ◽  
Open Field ◽  
Dry Matter ◽  
Starch Synthesis ◽  
Grain Filling ◽  
Dry Matter Accumulation ◽  
Wheat Cultivars ◽  
Temperature Regimes ◽  
Grain Starch ◽  
Chamber Temperature

Three wheat cultivars, namely, BARI Gom 25, BARI Gom 26, and Pavon 76, were sown in experimental field of Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur, in Bangladesh, on 18 November, 2013. Two temperature regimes, namely, normal (23°C in open field) and elevated (6 ± 1°C higher compared to open field mean air temperature in polythene chamber) temperature, were created immediately after anthesis to investigate the response of wheat cultivars to heat stress. Elevated temperature cuts back the duration of grain filling by 5 days in BARI Gom 25 and BARI Gom 26 and 10 days in Pavon 76. Starch synthesis was also cut back by the same duration in respective cultivars under elevated temperature condition. Results indicate that failure of conversion of sugar to starch rather than limited supply of sugar under high temperature condition was responsible for shortening of grain filling duration in all wheat cultivars. However, the response of elevated temperature on grain starch and main stem grain dry matter was less profound in BARI Gom 25 and BARI Gom 26 compared to Pavon 76 indicating their better tolerance to elevated temperature.

Effect of growth temperature on the high stearic and high stearic-high oleic sunflower traits

2013 ◽  
Vol 64 (1) ◽  
pp. 18 ◽  
Author(s):  
N. G. Izquierdo ◽  
L. A. N. Aguirrezábal ◽  
E. Martínez-Force ◽  
R. Garcés ◽  
V. Paccapelo ◽  
...  
Keyword(s):  
Fatty Acid Composition ◽  
Oleic Acid ◽  
Fatty Acid ◽  
Acid Composition ◽  
Oil Quality ◽  
Grain Filling ◽  
Effect Of Temperature ◽  
Gas Liquid Chromatography ◽  
High Oleic ◽  
Response To Temperature

We investigated variability in the response of oil fatty acid composition to temperature among high stearic and high stearic-high oleic sunflower (Helianthus annuus L.) genotypes. Two experiments were conducted with high stearic (including the CAS-3 mutation) and high stearic-high oleic inbred lines (including both the CAS-3 and the high oleic Soldatov mutations). Plants were cultivated in pots with soil, irrigated, and fertilised. Plants were exposed to different day/night temperatures during grain filling: 16/16°C, 26/16°C, 26/26°C, and 32/26°C. Oil fatty acid composition was determined by gas–liquid chromatography in seeds harvested after physiological maturity. Higher temperature during grain filling increased palmitic and oleic acid percentages and reduced stearic and linoleic acid percentages, suggesting some modifications on enzymatic activities. When the high oleic mutation was included, the variation in stearic and oleic acid percentages in response to temperature was reduced but not the variation in palmitic acid concentration. Variations in fatty acid composition in high stearic genotypes were mainly associated with night temperature as reported previously for traditional and high oleic hybrids. Knowing the effect of temperature on oil fatty acid composition in traditional and mutated genotypes is useful for selecting the environment in which to produce grains with the desired oil quality.

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