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.

Grain-filling of superior spikelets and inferior spikelets for japonica rice under low-amplitude warming regime in lower reaches of Yangtze River Basin

2021 ◽  
pp. 1-10
Author(s):  
Zhi Dou ◽  
Haixiang Zhang ◽  
Wenzhu Chen ◽  
Ganghua Li ◽  
Zhenghui Liu ◽  
...  
Keyword(s):  
Elevated Temperature ◽  
River Basin ◽  
Yangtze River ◽  
Yangtze River Basin ◽  
Grain Filling ◽  
Grain Weight ◽  
Sink Strength ◽  
Filling Rate ◽  
Grain Filling Period ◽  
Grain Filling Stage

Abstract Grain-filling, as the final growth stage of rice, is sensitive to environmental temperature change. Previous studies mainly concerned about the effects of high temperature stress during grain-filling on rice growth, and most experiments were carried out with pot for cultivating rice and greenhouse for warming. This research investigated the response of rice grain-filling of superior spikelets (SS) and inferior spikelets (IS) of two japonica cultivars to elevated temperature during grain-filling stage under open-field warming conditions in lower reaches of Yangtze River Basin using free-air temperature enhancement facility. Results indicated that rice yield was not significantly changed by warming less than 4°C. SS and IS showed different responses to elevated temperature during the grain-filling stage, whereas there were similar trends between two cultivars and years. For SS, although elevated temperature enhanced its filling rate during the early grain-filling period, and caused a shorter grain-filling period and a lighter grain weight; for IS, elevated temperature improved its grain weight by enhancing its filling rate during middle and late grain-filling period due to the increased number of days with suitable temperature. For both SS and IS, key starch biosynthesis enzymes and indole-3-acetic acid content exhibited generally a similar dynamics trend with grain-filling rates, and these sink strength parameters presented higher levels under elevated temperature relative to natural temperature for IS during middle and late grain-filling period. Consequently, warming less than 4°C presented different influences on SS and IS; the improvement of IS filling under warming regime was associated with the intensification of grain sink strength.

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.

Responses to Brief Periods of Elevated Temperature in Ears and Grains of Wheat

1983 ◽  
Vol 10 (6) ◽  
pp. 549 ◽  
Author(s):  
SS Bhullar ◽  
CF Jenner
Keyword(s):  
Elevated Temperature ◽  
Dry Matter ◽  
Soluble Sugars ◽  
Grain Filling ◽  
Grain Weight ◽  
Effect Of Temperature ◽  
Dry Matter Accumulation ◽  
Grain Number ◽  
Final Weight ◽  
Low Humidity

Brief warming of wheat ears reduced total grain weight, due mainly to a reduction in individual grain weight but also to a small reduction (2.6-12.8%) in grain number. Warming of ears reduced the water content of the grain, independently of humidity of the air with which the ears were warmed. Warming ears at high humidity accelerated the rate of dry matter accumulation as compared to warming at low humidity but both treatments resulted in a reduction of final weight per grain. The effect of temperature, and interaction with humidity, on grain dry matter accumulation are not due to changes in the water or osmotic potential of the grain. Warming the ears reduced temporarily the amount of sucrose and other soluble sugars in the grain, but not in the rachis or the floral organs. It seems unlikely that the supply of sugars available for distribution to the grain is depressed by elevated temperature, nor were reduced rates of grain- filling at elevated temperature simpiy related to apparent concentrations of sucrose within the grain: ripening and senescence of the pericarp were hastened by warming the ears, and these responses were not accompanied by reductions in the levels of sugars in the grain.

scholarly journals Grain filling parameters in high-yielding ns wheat cultivars

2008 ◽  
pp. 53-58
Author(s):  
Milka Brdar ◽  
Marija Kraljevic-Balalic ◽  
Borislav Kobiljski
Keyword(s):  
Multivariate Analysis ◽  
Nonlinear Regression ◽  
Environmental Conditions ◽  
Dry Weight ◽  
Grain Filling ◽  
Grain Weight ◽  
Cultivar Differences ◽  
Wheat Cultivars ◽  
Estimated Parameters ◽  
Grain Filling Duration

Grain yield of wheat is dependent on grain weight, which is the result of grain filling duration and rate. The study was undertaken to examine the relation between grain weight and rate and duration of grain filling in five high-yielding NS wheat cultivars. Stepwise multivariate analysis of nonlinear regression estimated grain filling parameters was used to examine cultivar differences in grain filling. On the basis of three-year average, the highest grain dry weight had cultivar Renesansa, and the lightest grains were measured for cultivar Evropa 90. Stepwise multivariate analysis indicated that all three nonlinear regression estimated parameters (grain weight, rate and duration of grain filling) were equally important in characterizing the grain filling curves of the cultivars studied, although sequence of their significance varied in different years, which is probably caused by different environmental conditions in three years of experiment.

Postanthesis green area duration in a semidwarf and a standard-height wheat cultivar as affected by sink strength

1994 ◽  
Vol 45 (7) ◽  
pp. 1337 ◽  
Author(s):  
GA Slafer ◽  
R Savin
Keyword(s):  
Grain Growth ◽  
Seedling Emergence ◽  
Grain Filling ◽  
Grain Weight ◽  
Soluble Carbohydrates ◽  
Sink Strength ◽  
Green Area ◽  
Ca 50 ◽  
Source Sink ◽  
The University

Postanthesis green area duration (GAD) has been associated frequently with yield. The senescence pattern of green organs is a major component of GAD. It has been proposed that delayed or accelerated senescence is strongly controlled by environmental conditions and the level of source or sink limitation on grain growth. In particular, it has been generally reported that the removal of reproductive structures delays the senescence process. However, results reporting this effect in wheat are not conclusive. A field experiment was conducted at the experimental station of The University of Melbourne comprising a factorial combination of a semidwarf and a standard-height wheat, and two levels of sink strength. At anthesis, 20 main shoots were tagged and detillered. Ten days after anthesis all the spikelets from one side of 10 tagged ears were removed by hand. The experiment was performed under natural, and 3 h-extended photoperiods from seedling emergence to heading. The photoperiod treatments induced differing grain filling environments and differing plant characteristics at onset of grain filling. Green area senescence was similar for both sink size treatments at any combination of cultivar and grain filling condition, indicating that the dynamics of plant senescence was insensitive to a severe reduction in number of grains per spike. Therefore, GAD was not significantly affected by the reduction in sink strength. The number of grains per spike were reduced to ca. 50% due to trimming. Therefore, source-sink ratio was doubled, but no significant changes in individual grain weight were found. There was no relationship between GAD and individual grain weight, confirming that grain growth in field-grown wheat is not limited by the strength of the source. Alternatively, our results confirmed that field-grown wheat is sink-limited during grain filling and that the likely accumulation of soluble carbohydrates in leaves does not affect the onset or rate of senescence.

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.

scholarly journals Effects of winter wheat season tillage on soil properties and yield of summer maize  

2017 ◽  
Vol 63 (No. 1) ◽  
pp. 22-28 ◽  
Author(s):  
Wang Yunqi ◽  
Zhang Yinghua ◽  
Wang Zhimin ◽  
Tao Hongbin ◽  
Zhou Shunli ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Winter Wheat ◽  
Bulk Density ◽  
Grain Filling ◽  
Soil Bulk Density ◽  
Grain Weight ◽  
Filling Rate ◽  
Summer Maize ◽  
Maize Production ◽  
Grain Filling Rate

The North China Plain (NCP) serves as China’s second most important maize production region. Rotary tillage, a popular method used in winter wheat/summer maize systems in the region, has adverse effects on maize production. The current study was conducted to determine whether rotary tillage after subsoiling in the winter wheat season (RS) improves the grain-filling rate and yield of summer maize by decreasing soil bulk density, when compared with rotary tillage (R), in the NCP. The RS treatment decreased soil bulk density and increased soil moisture in the summer maize season when compared with the R treatment. Root number under the RS treatment at 8 collar and silking stages was 22.4−35.3% and 8.0−11.7% greater than under the R treatment, respectively. The RS treatment significantly enhanced the grain-filling rate and grain weight as compared to the R treatment. Yield, thousand grain weight, biomass, and harvest index under the RS treatment were 7.7, 7.2, 2.3 and 5.3% higher than under the R treatment. Thousands grain weight was correlated with soil bulk density and soil moisture after silking. Consequently, the increase in grain weight and yield of summer maize resulted from the decrease in soil bulk density and a consequent increase in soil moisture, root number and grain-filling rate.  

Characterisation of a rice vacuolar invertase isoform, OsINV2, for growth and yield-related traits

2019 ◽  
Vol 46 (8) ◽  
pp. 777 ◽  
Author(s):  
Shamitha R. Morey ◽  
Tatsuro Hirose ◽  
Yoichi Hashida ◽  
Akio Miyao ◽  
Hirohiko Hirochika ◽  
...  
Keyword(s):  
Agronomic Traits ◽  
Flag Leaf ◽  
Grain Filling ◽  
Grain Weight ◽  
Growth And Yield ◽  
Wild Type ◽  
Vacuolar Invertase ◽  
Functional Roles ◽  
Structural Carbohydrate ◽  
Overexpression Phenotype

OsINV2, a rice vacuolar invertase isoform, was assessed for its functional roles in plant growth and development with key focus on its agronomic traits such as grain weight, grain filling percentage, grain number and dry weights at various stages until harvest. Lack of differences between the wild-type and the mutants with respect to any of the aforementioned traits tested revealed a possibility of functional compensation of OsINV2 in the mutants conceivably by its isoform. This was confirmed by OsINV2 promoter::GUS studies, where its spatial and temporal expression in the panicle elongation stages showed that although OsINV2 expression was observed from the stage with young panicles ~1 cm in length to the flag leaf stage, significant differences with respect to panicle and spikelet phenotypes between the wild-type and the mutant were not present. However, complement lines displaying an overexpression phenotype of OsINV2 possessed a higher stem non-structural carbohydrate content under both monoculm and normal tillering conditions. A trade-off between the spikelet number and grain weight in the complement lines grown under monoculm conditions was also observed, pointing towards the necessity of OsINV2 regulation for grain yield-related traits.

scholarly journals Estimating Organ Contribution to Grain Filling and Potential for Source Upregulation in Wheat Cultivars with a Contrasting Source–Sink Balance

Agronomy ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1527
Author(s):  
Carolina Rivera-Amado ◽  
Gemma Molero ◽  
Eliseo Trujillo-Negrellos ◽  
Matthew Reynolds ◽  
John Foulkes
Keyword(s):  
Grain Growth ◽  
Photosynthetic Rate ◽  
Grain Filling ◽  
Leaf Sheath ◽  
Grain Weight ◽  
Yield Potential ◽  
Wheat Cultivars ◽  
Sink Limitation ◽  
Source Sink ◽  
Source And Sink

Grain filling may be limited by the joint source and sink capacity in modern wheat cultivars, indicating a need to research the co-limitation of yield by both photosynthesis and the number and potential size of grains. The extent to which the post-anthesis source may be limiting final grain size can be estimated by partial degraining of spikes, while defoliation and shading treatments can be useful to estimate if any excess photosynthetic capacity exists. In the current study, degraining was applied to a set of 26 elite spring wheat cultivars from the International Maize and Wheat Improvement Center (CIMMYT)’s core germplasm (CIMCOG) panel, while lamina defoliation and shading through stem-and-leaf-sheath covering treatments were applied to a subset of the same cultivars. Responses to source treatments in grain weight, pre-anthesis reserve contribution to grain weight, dry-matter translocation efficiency, and flag-leaf and spike photosynthetic rate were measured and compared to an unmanipulated control treatment. Grain weight responses to degraining among cultivars ranged from no response to increases of 28%, suggesting a range of responses from sink limitation, to probable source and sink co-limitation of grain growth. Grain weight’s response to degraining increased linearly with the years of cultivar release from 1966 to 2009, indicating that the current highest yield potential CIMMYT spring wheats have a co-limitation of grain growth by source and sink. This may have been due to an increase in grain sink strength with years of cultivar release with no commensurate increase in post-anthesis source capacity. The relatively low decreases in grain weight with defoliation compared to decreases in light interception by defoliation indicated that sink limitation was still likely predominating in the cultivars with co-limitation. The stem-and-leaf-sheath covering treatment decreased grain weight by nearly 10%, indicating that stem-and-leafsheath photosynthesis plays a key role in grain growth during grain filling. In addition, pre-anthesis reserve contribution to grain weight was increased by ca. 50% in response to lamina defoliation. Our results showed that increasing the post-anthesis source capacity, through increases in stem-and-leaf-sheath photosynthetic rate during grain filling and pre-anthesis reserve contribution to grain weight, is an important objective in enhancing yield potential in wheat through maintaining a source–sink balance.

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