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Effect of high temperature on grain filling period, yield, amylose content and activity of starch biosynthesis enzymes in endosperm of basmati rice
Author(s) -
Ahmed Nisar,
Tetlow Ian J,
Nawaz Sehar,
Iqbal Ahsan,
Mubin Muhammad,
Nawaz ul Rehman Muhammad Shah,
Butt Aisha,
Lightfoot David A,
Maekawa Masahiko
Publication year - 2014
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.6941
Subject(s) - endosperm , amylose , amylopectin , starch synthase , starch , sucrose synthase , food science , chemistry , biochemistry , enzyme , biosynthesis , glycogen debranching enzyme , sucrose , glycogen phosphorylase , invertase
BACKGROUND High temperature during grain filling affects yield, starch amylose content and activity of starch biosynthesis enzymes in basmati rice. To investigate the physiological mechanisms underpinning the effects of high temperature on rice grain, basmati rice was grown under two temperature conditions – 32 and 22 °C – during grain filling. RESULTS High temperature decreased the grain filling period from 32 to 26 days, reducing yield by 6%, and caused a reduction in total starch (3.1%) and amylose content (22%). Measurable activities of key enzymes involved in sucrose to starch conversion, sucrose synthase, ADP ‐glucose pyrophosphorylase, starch phosphorylase and soluble starch synthase in endosperms developed at 32 °C were lower than those at 22 °C compared with similar ripening stage on an endosperm basis. In particular, granule‐bound starch synthase ( GBSS ) activity was significantly lower than corresponding activity in endosperms developing at 22 °C during all developmental stages analyzed. CONCLUSION Results suggest changes in amylose/amylopectin ratio observed in plants grown at 32 °C was attributable to a reduction in activity of GBSS , the sole enzyme responsible for amylose biosynthesis. © 2014 Society of Chemical Industry