Poster: Water Relations

Abs # 226: Effect of salt solution treatment on gas exchange and leaf water potential after root system removal in mangrove species

Presenter:	Kawamitsu, Yoshinobu , kawamitu@agr.u-ryukyu.ac.jp
Authors	Kawamitsu, Yoshinobu  (A)   Tokumaru, Keitarou  (A)   Naoko, Uehara  (A)
Affiliations:	(A): University of the Ryukyus, Fuc. of Agriculture

Mangrove is woody shrubs that dominant the coast and estuary, where high salinity conditions, in the tropical and subtropical regions. It is mentioned that mangroves are more extreme capacity for saline exclusion by the root system. In this experiment, the root system of mangrove was cut then treated in salt solution, after then, we conducted to measure gas exchange rate, chlorophyll fluorescence, water potential and NaCl accumulation for studying the mechanism of salt tolerance. In case of non-removing root system, the salt concentration in leaves of K. candel was lower than that in B. gymnorrhiza. After removing root system, the photosynthetic rate decreased in both species, but it decreased more slowly in B. gymnorrhiza. The Fv/Fm value was found to decrease remarkably in K. candel which was removed root system and treated in 400mM NaCl concentration. At high NaCl concentration of treatment solution, the Na content was found to increase in the leaves of K. candel, whereas it did not increase in B. gymnorrhiza. It was signified that the water potential decreased rapidly in both K. candel and B. gymnorrhiza in sorbitol treated condition.