Changes in ion contents in apoplast of Pharbitis nil

Abstract

Apoplastic sap was collected from Pharbitis nil by a pressure cylinder (Nozaki et al. 2003), and apoplastic ions were analyzed by ioncromatography. Hypocotyls of seedlings were cut, and the sap from each cut end of root (R) and cotyledon (C) side was collected as 0 MPa apoplastic sap (R0, C0). Next apoplastic sap was collected from root and cotyledon side pressurized with 0.5 and 1 MPa (R0.5, C1), respectively. Concentration of almost all ions of C0 was about 2 times higher than that of R0, while the concentration of C1 was lower than that of R0.5. Though NO3^- was detected in root side, it was not detected in cotyledon side. Then changes in cations of apoplastic sap from cotyledon side were analyzed. Ca²⁺ concentration of C0 under SD condition was higher than under LD. K⁺, Mg²⁺, and Ca²⁺ concentrations of C1 changed photoperiodically.