Sink strength in relation to growth of superior and inferior grains within a wheat spike

2010 ◽  
Vol 148 (5) ◽  
pp. 567-578 ◽  
Author(s):  
S. YAN ◽  
W. LI ◽  
Y. YIN ◽  
Z. WANG
Keyword(s):  
Accumulation Rate ◽  
Soluble Starch ◽  
Cell Number ◽  
Starch Synthase ◽  
Grain Weight ◽  
Starch Accumulation ◽  
Sink Strength ◽  
Endosperm Cell ◽  
Compact Spike ◽  
Wheat Spike

SUMMARYStarch is a major component of wheat grain and, to a great extent, determines the grain weight. Starch accumulation in wheat (Triticum aestivum L.) is closely associated with sink strength. Four winter wheat cultivars, Lumai 21 and Jimai 20 (compact-spike cultivars) and Shannong 1391 and Shannong 12 (loose-spike cultivars) were grown to evaluate the amylose and amylopectin accumulation in both superior and inferior grains (higher and lower individual grain weight, respectively) and the relationship between starch accumulation and sink strength. In general, superior grains showed a higher starch accumulation rate, endosperm cell number and activity of enzymes including sucrose synthase (SS), uridine diphosphorate glucose pyrophosphorylase (UGPP), adenosine diphosphorate glucose pyrophosphorylase (AGPP), soluble starch synthase (SSS) and granule-bound starch synthase (GBSS), and subsequently produced higher starch accumulation and grain weight than inferior grains. Greater differences in starch accumulation and grain weight were found between the two classes of grains for compact-spike cultivars than between those for loose-spike cultivars. These results suggest that the grain sink strength, determined by endosperm cell number and the activity of synthesis-related enzymes, is closely associated with starch accumulation in superior and inferior grains on a wheat spike.

scholarly journals EVALUACIÓN DE LA EXPRESIÓN DE GENES IMPLICADOS EN LA BIOSÍNTESIS DE ALMIDÓN EN DIFERENTES VARIEDADES DE YUCA

2014 ◽  
Vol 20 (2) ◽  
Author(s):  
Simón Pedro Cortés Sierra ◽  
Paul Chavarriaga ◽  
Hernán Ceballos ◽  
Camilo Ernesto López Carrascal
Keyword(s):  
Gene Expression ◽  
Soluble Starch ◽  
Matter Content ◽  
Starch Synthase ◽  
Starch Accumulation ◽  
Dry Matter Content ◽  
Storage Roots ◽  
Expression Levels ◽  
Study Gene Expression ◽  
Cassava Varieties

<p>Las raíces almacenadoras de yuca representan una fuente importante de almidón. La ruta metabólica del almidón ha sido reconstruida recientemente en yuca gracias a la liberación de la secuencia completa de su genoma. En este estudio se evaluó la expresión de los genes que codifican para las enzimas Pululanasa, Isoamilasa, α-amilasa, Enzima Desproporcionante, ADP-glucosa pirofoforilasa, Almidón sintasa unida al gránulo, Enzima ramificante del almidón y Sintasa soluble del almidón, en las raíces almacenadoras de plantas de 5 y 11 meses de edad, en un grupo de cinco variedades de yuca. Se evidenciaron diferencias importantes en la expresión de estos genes entre las variedades evaluadas y entre los dos tiempos. Las variedades CM523-7 y SM1219-2 presentaron uno de los niveles más altos de expresión para los genes ADP-glucosa pirofoforilasa y Almidón sintasa unida al gránulo mientras que el gen para α-amilasa fue el más bajo en estas dos variedades. Aunque  la variedad TMS60444 presentó niveles de expresión similares en genes implicados en la síntesis de almidón, fue la que presentó el mayor nivel de expresión de la α-amilasa. Estos datos se pueden correlacionar con el relativo bajo contenido de materia seca en esta variedad. Los datos de expresión génica presentados en este trabajo permitirán complementar información sobre actividad enzimática con miras a identificar los elementos más importantes en la acumulación diferencial de almidón entre variedades de yuca.</p><p><strong>ABSTRACT</strong></p><p>Cassava storage roots represent an important starch source. Recently, the starch metabolic pathway in cassava has been reconstructed thanks to the full release of its genome. In this study gene expression was evaluated for genes coding Pullulanase, Isoamylase, α-amylase, Deproportionating enzyme, ADP-glucose pyrophosphorylase, Granule bound starch synthase, Starch branching enzyme and Soluble starch synthase, in cassava storage roots 5 and 11 months old, in 5 cassava varieties. Important gene expression differences were detected both at the variety and time level. CM523-7 and SM1219-2 showed one of the highest expression levels for AGPase and GBSS genes, while α-amylase showed the lowest level in these two varieties. TMS60444 variety showed similar expression levels in starch biosynthesis-related genes, but conversely also showed the highest α-amylase expression. This correlates with the relative low dry-matter content in TMS60444. Gene expression data reported here will allow complementing actual information on enzymatic activity, in order to identify the most relevant factors in differential starch accumulation between cassava varieties.</p><br /><p> </p>

Relationship between Starch Accumulation and Activities of the Related Enzymes in the Leaf Sheath as a Temporary Sink Organ in Rice (Oryza sativa)

1997 ◽  
Vol 24 (5) ◽  
pp. 563 ◽  
Author(s):  
Yoshito Watanabe ◽  
Yasunori Nakamura ◽  
Ryuichi Ishii
Keyword(s):  
Biosynthetic Pathway ◽  
Starch Content ◽  
Soluble Starch ◽  
Leaf Sheath ◽  
Starch Synthase ◽  
Starch Accumulation ◽  
Regulation Mechanism ◽  
Rice Plants ◽  
Fructose 1,6 Bisphosphatase ◽  
The Relationship

The starch stored temporarily in the leaf sheath of rice plants is translocated to the grain, contributing to the grain yield. In this paper, the relationship between starch accumulation and the activities of enzymes involved in the starch biosynthetic pathway in the leaf sheaths of rice plants was examined to elucidate the regulation mechanism of starch accumulation in the temporary sink organ. When the starch content was compared between different leaf sheath positions on the main stem, the 14th leaf sheath counted from the bottom, which elongated just before anthesis, showed about a four-fold higher value than the 10th leaf sheath. Among the enzymes involved in carbohydrate metabolism, the activity of starch branching enzyme (BE, EC2.4.1.18) was greatly higher in the 14th leaf sheath than in the 10th leaf sheath, while that of ADPglucose pyrophosphorylase (EC2.7.7.27) was similar between the two leaf sheaths. The starch content increased rapidly in the period around anthesis in the 12th and 14th leaf sheaths, but did not in the 10th and 11th leaf sheath. In the higher leaf sheath position, the activity of BE changed with noticeably similar trend to the starch content. Soluble starch synthase (SSS, EC2.4.1.21), granule-bound starch synthase (GBSS, EC2.4.1.21) and plastidial fructose- 1,6-bisphosphatase (FBPase, EC3.1.3.11) were also significantly correlated with the starch content. These results suggest that BE is involved in regulation of starch metabolism, possibly in collaboration with other enzymes such as SSS, GBSS and plastidial FBPase in temporary sink organs like the leaf sheath.

Association Between Concentration of Organic Nutrients in the Grain, Endosperm Cell Number and Grain Dry Weight Within the Ear of Wheat

1982 ◽  
Vol 9 (1) ◽  
pp. 83 ◽  
Author(s):  
BK Singh ◽  
CF Jenner
Keyword(s):  
Amino Acids ◽  
Inverse Relationship ◽  
Dry Weight ◽  
Cell Number ◽  
Grain Weight ◽  
Endosperm Cell ◽  
Cell Numbers ◽  
Carbohydrate Concentration ◽  
Organic Nutrients ◽  
Number Of Cells

The present investigation was conducted to examine the association between the concentrations of sugars and amino acids in the grain, cell number in the endosperm and final dry weights of grains at various positions within the ear of wheat. Variation in the grain weight within a spikelet or between spikelets was dependent upon the number of cells formed in the endosperm. Concentrations of assimilates measured in the grain, however, showed either no relationship or an inverse relationship with the endosperm cell numbers. Variation in cell number in the endosperm between spikelets inserted at different positions on the rachis was not related to the carbohydrate concentration in the sections of rachis bearing the respective spikelets.

scholarly journals Toward an understanding of the biogenesis of the starch granule. Determination of granule-bound and soluble starch synthase functions in amylopectin synthesis.

1994 ◽  
Vol 269 (40) ◽  
pp. 25150-25157
Author(s):  
M.L. Maddelein ◽  
N. Libessart ◽  
F. Bellanger ◽  
B. Delrue ◽  
C. D'Hulst ◽  
...  
Keyword(s):  
Starch Granule ◽  
Soluble Starch ◽  
Starch Synthase

scholarly journals QTL-seq identifies cooked grain elongation QTLs near soluble starch synthase and starch branching enzymes in rice (Oryza sativa L.)

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Siwaret Arikit ◽  
Samart Wanchana ◽  
Srisawat Khanthong ◽  
Chatree Saensuk ◽  
Tripop Thianthavon ◽  
...  
Keyword(s):  
Oryza Sativa ◽  
Oryza Sativa L ◽  
Soluble Starch ◽  
Starch Synthase ◽  
Starch Branching Enzymes ◽  
Branching Enzymes

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.

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