The determination of the D.P.D. of Satsuma orange leaves (Citrus unshiu MARC.) by the Chardakov Dye method

Abstract

Measurements of the diffusion pressure deficit (D.P.D.) of Satsuma orange trees (Citrus unshiu MARC.) growing both in pots and field were carried out by the Chardakov Dye method, There was negative correlation between the D.P.D. and soil moisture content, and the inflextion point seemed to lie near the moisture equivalent. As the water saturation deficit (W.S.D.) was positively correlated with the D.P.D., it may be used to estimate the D.P.D., but it takes many more hours to measure the W.S.D. than to measure the D.P.D. by this dye settling method. The diurnal change of the D.P.D in winter took place at a higher and narrower range than in summer.