Abstract: The effects of blue light (BL) on callus growth and respiration in hypocotyl callus of mung bean ( Vigna radiata (Linn.) Wilczek) were investigated. The results showed that BL could promote callus formation and growth as compared with white light (WL) and the darkness (D). On the eighteenth day after culture, the fresh weight of calli cultured in BL was 120% and 191.5% of those in WL and in D respectively. The respiratory rate in calli measured on the fifth day after culture was greatest in BL, and lowest in D. However, the order of respiration rate was reversed when measured on the fourteenth day after cultured. The results from the experiments with inhibitors (iodoacetic acid + malonate, or Na3 PO4) and by measuring the activity of phosphogloconic dehydrogenase(G-6-PDH) suggested that hexose monophospate pathway (HMP) increased in BL and in WL 5 days later, because the residual respiration inhibited by iodocacetic acid + malonate was 34% ~ 36% of total one, which was inhibited by Na3PO4; While it was 9% - 11% in D. G-6-PDH activity in BL was much greater than in D, especially the fifth day after culture. The cyanide-resistant pathway occurred in mung bean hypocotyl. The capacity of this respiration in D was greater than that in BL or in WL. The fourteenth day after culture, it reached about 31% in D, but less than 20% in BL or in WL.

Key words: Mung bean, Blue light, Callus, Respiration