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Effect of sucrose on activity of starch synthesis enzymes in rice ears in culture
Author(s) -
Sasaki Haruto,
Edo Ei,
Uehara Naoko,
Ishimaru Tsutomu,
Kawamitsu Yoshinobu,
Suganuma Shihoko,
Ueda Daisuke,
Ohsugi Ryu
Publication year - 2005
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.2005.00520.x
Subject(s) - sucrose , starch , carbohydrate , sucrose synthase , enzyme , oryza sativa , biochemistry , starch synthase , sucrose phosphate synthase , chemistry , food science , enzyme assay , sink (geography) , biology , invertase , gene , amylopectin , amylose , cartography , geography
Grain filling of rice ( Oryza sativa L.) is thought to be affected not only by the supply of carbohydrate from source organs, but also by sink activity, including the activities of enzymes related in starch synthesis. To examine the effect of translocated carbohydrate on sink activity, we cultured detached ears (cut 7 days after flowering) in a solution containing sucrose at various concentrations, glutamine and vitamins. Grain weights 16 days after the start of ear culture increased with increasing sucrose concentration up to 50–70 g sucrose l −1 , but not above this range, probably because of low water potential. Activities of ADP glucose pyrophosphorylase, soluble starch synthase and sucrose synthase rapidly decreased in grains grown without sucrose, but increased with increasing sucrose concentration up to 50–70 g l −1 . Expression of mRNAs for these enzymes and for sucrose transporter was also generally increased by sucrose at 50–70 g l −1 . Though there was a good correlation between activity and expression of mRNA for sucrose synthase, the correlation for other enzymes was not very good. Thus, we suggested that the sink activity of grains in rice ears, and therefore the grain filling, was affected by the supply of carbohydrate from source organs, and that it was also owing to factors other than transcriptional regulation.