Abstract:

The changes in physio-biochemical indexes and γ-aminobutyric acid (GABA) content during germination of
five maize cultivars under hypoxia stress were investigated. Results showed the physiological and biochemical indexes
of five maize cultivars significantly changed during 72 h germination under hypoxia. At the end of germination, the
sprout length increased to 15.5－26.3 mm, the respiratory rate was improved by 1.7－3.2 folds, the dry matter was lost by
35.6%－40.6%, the starch content was consumed by 15.5%－28.9%, and the content of reducing sugar and free amino acids
increased by 1.7－4.7 and 7.4－13.3 folds, respectively. GABA content in germinated maize increased by 9.3－13.2 folds
when compared with the original maize. Furthermore, significant differences in GABA content and germination rate among
different maize cultivars during germination were observed. Germination rate of cultivar ZHN was the highest (85.5%) with
a maximum GABA content of 0.65 mg/g md. Hence, ZHN could be considered as a good source for GABA accumulation.
GABA content in maize during germination under hypoxia revealed a significantly (P ＜ 0.01) positive correlation with
sprout length, respiration rate and free amino acid content, respectively. The nutritional quality of maize could be improved
through germination under hypoxia stress.

Key words: maize, germination, hypoxia stress, γ-aminobutyric acid