Physiological responses of the mangrove Rhizophora mangle grown in the absence and presence of NaCl.

摘要: Abstract. Propagules of the mangrove, Rhizophora mangle L., were precultivated for 9 months in a greenhouse. The young plants transferred into unaerated nutrient solutions without and with 200 mol m 3 NaCl subsequently their growth, water relations photosynthetic properties leaves studied. Growth salttreated was significantly increased, while control gradually died off after finishing experiments. shoot potential stomatal resistance lowered chlorophyll contents a/b ratio salt-treated increased by NaCl, net result being an enhanced rate CO2 assimilation. both sets showed diurnal fluctuations malic acid concentration which more pronounced salt treated which, additionally, succulent. However, no fixation at night, indicating that is CAM-cycling plant. After d cultivation or Na+, Cl K+ concentrations tissues vacuoles measured. Energy-dispersive X-ray microprobe analyses on root reveal Na+ preference, those strong preference. Vacuolar are neither affected nor do they vary across radius. High vacuolar found hypodermis followed stepwise decrease towards inner cortex cells. Ion photosynthetically active leaf seem to be regulated (1) radial filtration cortex: (2) ion exchange xlem parenchyma cells: (3) sequestration hypodermal storage tissue leaves.