Enrichment of sugar content in melon fruits by hydrogen peroxide treatment.
Since sweetness is one of the most important qualities of many fruits, and since sugars are translocated from leaves to fruits, the present study investigates photosynthetic activity, activity of sugar metabolizing enzymes, sugar content in leaves and fruits and endogenous levels of hydrogen peroxide in leaves of melon plants treated with various dilutions of hydrogen peroxide, a nonspecific signaling molecule in abiotic stress. For this purpose, 4-month-old melon plants were treated with various concentrations (<50mM) of hydrogen peroxide by applying 300 mL per day to the soil of potted plants. The treatments resulted in increased fructose, glucose, sucrose and starch in the leaves and fruits. The most effective concentration of hydrogen peroxide was 20mM. During the day, soluble sugars in leaves were highest at 12:00 h and starch at 15:00 h. Furthermore, the peroxide treatment increased the photosynthetic activity and the activities of chloroplastic and cytosolic fructose-1,6-bisphosphatase, sucrose phosphate synthase and invertases. Thus, our data show that exogenous hydrogen peroxide, applied to the soil, can increase the soluble sugar content of melon fruits.
Graduate School of Bioagricultural Sciences, Nagoya University, Chikusa, Nagoya, Japan.
Keiko
K
Ozaki
Akio
A
Uchida
Tomoko
T
Takabe
Fumi
F
Shinagawa
Yoshito
Y
Tanaka
Teruhiro
T
Takabe
Takahisa
T
Hayashi
Tasuku
T
Hattori
Ashwani K
AK
Rai
Tetsuko
T
Takabe
D018533:Biomass; D050260:Carbohydrate Metabolism / Q000187:drug effects* / Q000528:radiation effects; D002940:Circadian Rhythm / Q000187:drug effects / Q000528:radiation effects; D019662:Cucurbitaceae / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism* / Q000528:radiation effects; D006597:Fructose-Bisphosphatase / Q000378:metabolism; D005638:Fruit / Q000187:drug effects* / Q000378:metabolism* / Q000528:radiation effects; D005964:Glucosyltransferases / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000378:metabolism / Q000494:pharmacology*; D008027:Light; D010788:Photosynthesis / Q000187:drug effects / Q000528:radiation effects; D018515:Plant Leaves / Q000187:drug effects / Q000201:enzymology / Q000528:radiation effects; D018547:Plant Stems / Q000187:drug effects / Q000378:metabolism / Q000528:radiation effects; D012995:Solubility / Q000187:drug effects / Q000528:radiation effects; D013213:Starch / Q000378:metabolism; D043324:beta-Fructofuranosidase / Q000378:metabolism
D013213:Starch; D006861:Hydrogen Peroxide; D005964:Glucosyltransferases; C022698:sucrose-phosphate synthase; D006597:Fructose-Bisphosphatase; D043324:beta-Fructofuranosidase