[Sugar metabolism and its regulation in postharvest ripening kiwifruit].
Kiwifruit (Actinidia deliciosa cv. Bruno) was used to investigate starch and sugar metabolism and the mechanisms of regulation by acetylsalicylic acid (AsA 1.0 mmol/L, pH 3.5), low temperature (0 degrees C) and ethylene (100 microL/L) treatments. There was an increase in amylase activity at the initial stage followed by dramatical decrease in starch content and a rapid increase in hexose content at the rapid stage of fruit ripening and softening, which was associated with an increase in SPS activity, a decrease in acid invertase activity, and the accumulation of sucrose. AsA and low temperature treatments inhibited the amylase activity, slowed down the hydrolysis of starch and the accumulation of hexoses, suppressed the rise of SPS activity and the decline of acid invertase activity in the ripening fruit. The accumulation of sucrose was delayed by AsA and low temperature treatments. However, ethylene application induced amylase activity, accelerated starch hydrolysis, and raised the hexose content. The SPS activity also increased and the sucrose accumulated in the presence of ethylene. It is suggested that the SPS may play a key role in sugar metabolism of postharvest kiwifruit, and it could be activated by hexose and feedback-inhibited by sucrose. AsA, low temperature and ethylene treatments regulate sugar metabolism probably through influencing the SPS activity.
Zhang
Yu
Y
The State Agriculture Ministry Laboratory of Horticultural Plant Growth, Development and Biotechnology, Laboratory of Fruit Molecular Physiology and Biotechnology, Huajiachi Campus, Zhejiang University, Hangzhou 310029 China.
Chen
Kun-Song
KS
Zhang
Shang-Long
SL
Wang
Jian-Hua
JH
D029042:Actinidia / Q000378:metabolism*; D001241:Aspirin / Q000494:pharmacology; D050260:Carbohydrate Metabolism; D005030:Ethylenes / Q000494:pharmacology; D013403:Sugar Phosphates / Q000096:biosynthesis; D013696:Temperature
D005030:Ethylenes; D013403:Sugar Phosphates; C036216:ethylene; D001241:Aspirin