Influence of salinity on vegetative growth and photosynthetic pigments of bitter almond rootstock

Bitter almond rootstock is considered one of the most vital rootstocks for stone fruit species but it is classified as a plant sensitive to salinity. This experiment was carried out to study the effect of salt stress on vegetative growth and photosynthetic pigments of bitter almond rootstock as an attempt to sustain growth and increase its tolerance to high salt concentrations. However, the seeds were soaked in salt solution of NaCl as 1, 3, and 5 dsm-1 for 48 hours before stratification. After that, nuts were sown in perlite and treated with different saline solutions subsequently stratified at 6 ℃ for eight weeks. Sprouted seeds were cultivated in pots with a mixture of peat and perlite and treated only with the highest salt concentration 5 dsm-1. The treatments were arranged in a complete randomized block design with three replications. Vegetative traits and photosynthetic pigments content were estimated. The results revealed that soaking and pre-treating seed of bitter almond rootstock by means of high salt concentration 5dsm-1 during the germination period and subsequently after planting produced stronger transplants that had hardening, adaptation and could avoid the hyperosmotic shock of salt stress after planting. It is obvious throughout; increment of stem diameter, plant height, total number of leaves\plant, fresh and dry weight of leaves, photosynthetic pigments and total carbohydrate content of such transplants. While other coming seedlings from low salt concentrations were exposed to hyperosmotic shock and salt injury therefore inhibit growth rate of such plants, increased falling of leaves and finally reduced photosynthetic pigments content in the resulting seedlings.