Cell and Tissue Journal

Abstract Aim: In the current study, the effect of growth regulators, type and composition of the culture medium, genotypes of the used cultivars and type of explants were investigated on the ability of callusing and regeneration of wheat cultivars.
Material and methods: two culture media (N6, MS), three immature embryos, mature embryos and leaf cuttings were used. N6 medium containing growth regulator 2, 4-D was used for callusing of embryo and the leaf pieces, but for regeneration N6 medium containing growth regulators NAA, BAP and Kin was used. For calligraphy and regeneration of immature embryos, MS medium containing a variety of growth regulators were used.
Results: Callus induction and regeneration differed based on the genotype, type of explants and media composition. Chamran variety had the highest rate of callus and regeneration from immature embryo. For the adult embryo, the highest level of calligenesis and regeneration related to the C-D-9 line. In the case of leaf parts, the highest level of callus related to the C-D-9 at the level of 2, 4-D (2.4mg/L). The highest percentage of shoots belonged to the C-D-9 line that was obtained in N6 medium (6) containing IAA (1mg/L) + BA (1mg/L).
Conclusion: Response to tissue culture in wheat is affected by several factors such as genotype, type of explants, growth regulators. Results proved that the type and concentration of used growth regulators in the culture medium differ among cultivars for callus induction and wheat regeneration. The most important factor affecting wheat cultivation was immature embryo explant and the genotype type of the used cultivar.
 

Abstract Aim: In this study, the effect of salinity stress on quantitative gene expression of sucrose synthase1, relative water content and the uptake ratio of sodium to potassium in the leaves of wheat were evaluated.
Material and Methods: Wheat seedlings treated with 100 and 200 mM sodium chloride and at times zero, 6, 12, 24 and 36 hours after treatment relative water content, the uptake ratio of sodium to potassium in the leaves and quantitative gene expression of Sus1 by qRT-PCR method were studied. 
Results: Results showed a significant decrease in relative water content, increase in the uptake ratio of sodium to potassium by leaves and increase in the relative expression of sucrose synthase1 gene at treated plants compared to control group.
Conclusion: Generally, increase in the expression of sucrose synthase 1 gene could be one of the possible mechanisms in the process of tolerance to salinity stress.

Abstract Aim: In this investigation the effect of salt stress on the early developmental stages of dark-grown wheat seedling was studied.
Materials and methods: Grains of the salt tolerant (Seds1) and the susceptible (Giza168) cultivars of wheat were germinated and grown in darkness in nutrient solution supplied with or without 200 mM NaCl. The protochlorophyllide content was determined. The fluorescence emission intensity ratio of 655/633 nm was measured. The ratio of newly formed Chlorophyllide to non-photoactive Pchlide was measured after irradiation of leaf sections with one single flash to estimate the degree of phototransformation. The chlorophyll a content was also determined after dark-grown leaf sections were irradiated.
Results: The salt stress treatment caused a marked increase in protochlorophyllide (Pchlide) content in dark-grown material and in Chlide content after irradiation of leaf sections of both varieties. The relative ratio of phototransformable to non-phototransformable pchlide and of newly formed chlorophyllide (Chlide) was influenced by salt stresse. The results were influenced by the different growth rates found for stressed and unstressed seedlings. Leaf sections from seedlings grown under salt stress in darkness accumulates more chlorophyll a than leaf sections from unstressed seedlings when floating on nutrients or on a 200 mM NaCl solution in continuous white light.
Conclusion: The increased accumulation of the long-wavelength form of Pchlide is suggested to be an expression for the mobilization of a part of the protective mechanisms against salt stress.
 

Abstract Aim: In this study we have used two wheat varieties with different tolerance to salt in different concentration of solt.
Material and Methods: Giza 168, Seds 1 plants have been grown for seven days in Hoagland solution and some of them were grown in Hoagland solution supplemented with 200 mM extra salt. Cutted leaf segments from these plants incubated with 600 mM salt. Dark-grown pre-adapted, with 200mM extra salt, plants were illuminated to determine the chlorophyll accumulation in two varieties.
Results: The maximum photochemical efficiency, Fv/Fm, stayed the same for all measurements. Measurement of relative ETR showed that the tolerant variety, Seds 1, had higher values for ETR than the susceptible variety (Giza 168). Also the measurement showed that the salt adapted samples of both varieties better withstood the excess of salt applied than the non-adapted samples.
The chlorophyll content was higher for the tolerant variety compared to the susceptible. The chlorophyll accumulation of the tolerant samples pre-adapted with or without salt showed no dramatic differences. The susceptible sample, Giza 168, however, accumulated more chlorophyll if pre-adapted to salt before being exposed to high salt concentration.
Conclusion: PSII seems to be stable and unaffected at the functional level by salt stress. The tolerant variety is better adapted to salt stress. It seems to be due to the advantage of having a more efficient photosynthetic apparatus.