亜鉛の過不足によるカイワレダイコン(Raphanus sativus L. ‘Kaiwaredaikon’)スプラウトの亜鉛濃度および遺伝子発現量への影響

抄録

Radish sprouts (Raphanus sativus L. ‘Kaiwaredaikon’) were hydroponically cultivated in an environment exposed to zinc at a level of 0, 20, 50, 100, and 200 ppm as zinc sulfate. Growth was inhibited in sprouts exposed to zinc at a level of 50 ppm or more. Zinc contents in sprouts increased in a manner that was dependent on zinc exposure levels up to ppm; the zinc content in sprouts exposed to 100 ppm was 83.3 μg/g fresh weight. However, no significant differences were observed in vitamin C or chlorophyll contents in sprouts irrespective of zinc exposure levels. A DNA microarray analysis was conducted and revealed that the expression of 1275 genes was significantly different between radish sprouts exposed to zinc at a level of 20 ppm and those exposed to a zinc deficiency, whereas the expression of 1379 genes was altered by a zinc excess. Gene ontology terms related to organic acid metabolism, response to a stimulus, carbohydrate metabolism, lipid metabolism, and aromatic metabolism were significantly enriched with exposure to zinc at a level of 0 ppm, while response to a stimulus, organic acid metabolism, lipid metabolism, and oxidation reduction were significantly enriched with exposure to zinc at a level of 100 ppm. No significant differences were observed in zinc transporters with a zinc excess and deficiency. These results indicate that hydroponic cultivation in an environment exposed to zinc is useful for producing radish sprouts with higher zinc contents.