A comparative study was performed on Avicennia marina from two sites of New South Wales prevailed by different salinity conditions. In Kurnell, the average salinity was 17 PPT, whereas by the river Parramatta soil salinity was approximately 3 PPT. Assimilation rate was higher in saline condition due to salt induced increment in mesophyll and total chlorophyll, whereas, considerable restriction was imposed on transpiration, vapour pressure defict and stomatal conductance in spite of higher stomatal frequency in sea-side plants. The significant positive relation between photosynthesis and water efflux in non-saline condition contradicted with the clustering of carbon assimilation within a low range of transpiration and stomatal conductance in enhanced salinity. Despite regulated water efflux in the saline habitat, leaf temperature did not rise as much as to cause photoinhibition, thus remained lower than that in the fresh water condition. However, in both the habitats, leaf temperature seemed to increase under controlled transpiration rate. Except the positive correlations between photosynthesis and water efflux, the other parameters viz., leaf temperature and vpd with assimilation, transpiration and leaf temperature with vpd followed inverse trends with their related variables. In elevated salinity, the relation of photosynthesis was insignificant with water efflux, stomatal behaviour, vpd and leaf temperature, thus pointed to the beneficial interference of saline environment on carbon assimilation of A. marina.
Paramita Nandy (Datta) , Sauren Das , Philip Groom , Elizabeth Kabanoff , Monoranjan Ghose and Robert Spooner-Hart , 2007. On the Physiological Responses of Avicennia marina (Forsk.) Vierh. From Sydney, Australia in Different Salinity Conditions
. Research Journal of Botany, 2: 33-40.