Accumulation of sugars in cucumber cucumis sativus cultivar seiriki no. 2 leaves during calcium starvation
Matsumoto, H.; Teraoka, K.
Plant and Cell Physiology 21(8): 1505-1514
ISSN/ISBN: 0032-0781 Accession: 004653237
The metabolic role of Ca was determined with cucumber plants; plants were grown without Ca. Symptoms of leaf injury such as chlorosis and marginal curling appeared a few days after the removal of Ca. The level of the soluble sugars in Ca deficient leaves increased to more than 10 times that in the control at the late stage of treatment. The level of the soluble sugars in the root decreased because of the Ca deficiency. The contents of soluble and bound Ca, in contrast to soluble sugars, decreased only in the young leaves of Ca deficient plants. The content of each soluble sugar measured by liquid chromatography was stable in the control leaves during treatment. Changes in sucrose, fructose, glucose, maltose and galactose in Ca deficient leaves were similar to the change in the total soluble sugars. The increases in stachyose and the mixture of raffinose and cellobiose occurred at the late stage of Ca starvation. The starch content in Ca deficient leaves was higher than that of the control, except for the remarkable decrease in the late stage. .alpha.-Amylase activities were not altered either in the control or in the Ca deficient plants during 5 days of treatment, but a clear increase took place at the late stage of Ca starvation. The distinct increase in the soluble sugars in Ca deficient leaves may be due to the decline in transport caused by the Ca deficiency.