Abstract:
Salinity is thought to be a limitation for growth of several economic crops worldwide. In this
work we examine the effects of different concentrations of NaCl (0, 50 and 100 mM) on
photosynthetic pigments, chloroplast ultrastructure and carbohydrate pool of two tomato
cultivars differing in salt tolerance, a salt sensitive variety (GS12) and a salt tolerant cultivar
(Adora). Salt stress caused a decrease in Chl a content and a significant increase in Chl b content,
this effect being most pronounced in Adora leaves. GS12 chloroplasts were affected adversely
due to salinity treatment as they appeared elongated with less garana and much developed starch
grains. Meanwhile Adora chloroplasts seemed to tolerate salinity stress being oval in shape with
well-stacked grana. Carbohydrate pool in both cultivars was decreased due to salinity treatment
but 50 mM NaCl treated leaves in both cultivars showed increased total carbohydrate than that of
control leaves. It is apparent that Adora plants tolerated salinity stress well as the photosynthetic
machinery and chloroplast ultrastructure appeared to be able to accommodate with such stress in
a very impressive manner. |
