نوع مقاله : مقاله پژوهشی
نویسندگان
1 دانش‌آموخته کارشناسی ارشد، گروه اصلاح نباتات و بیوتکنولوژی کشاورزی، دانشگاه علوم کشاورزی و منابع طبیعی گرگان، گرگان، ایران
2 گروه اصلاح نباتات و بیوتکنولوژی، دانشگاه علوم کشاورزی و منابع طبیعی گرگان، گرگان، ایران
3 دانشجوی دکتری، گروه اصلاح نباتات و بیوتکنولوژی کشاورزی، دانشگاه علوم کشاورزی و منابع طبیعی گرگان، گرگان، ایران
چکیده
کلیدواژه‌ها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Introduction
Salinity is one of the most important limiting factors for the production of all agricultural products in many regions of the world. In saline environments, the absorption of nutrients in plants is reduced. Adaptation of plants to environmental stresses requires morphological, physiological, and biochemical changes, including the accumulation of osmolytes, which can play an adaptive role during osmotic stress. One of the common responses of plants to osmotic stress is the accumulation of proline, which is an important and well-known osmolyte that accumulates in many plant organs during stress. The objective of the present study was to evaluate the expression pattern of P5CS and P5CR genes and to investigate some physiological traits in two bread wheat varieties at the early growth stages under salinity stress conditions.
Materials and methods
The experiment was conducted as a split plot factorial in completely randomized design with four replications. The seeds of the studied wheat cultivars were disinfected using 10% ethanol and washed with distilled water, and then sown in 32 pots filled with cocopeat and perlite in a ratio of 2:1. Fifteen seeds of each variety were sown in each pot. Salinity stress was applied after germination and establishment of the seedlings with irrigation water, so that during the irrigation of plants, the control pots were irrigated with strile distilled water (0 dS/m) and the salinity treatment pots were irrigated with saline water containing NaCl (12 dS/m). After the plants reached the tillering and stemming growth stages, five plants were randomly sampled from each experimental pot, and biochemical traits including chlorophyll, proline, cellular oxidation index, potassium and sodium levels were measured at both growth stages. The expression of some genes including P5CS and P5CR was also evaluated on leaf samples.
Research findings
The results of this experiment showed that the effects of salinity stress and variety on all measured biochemical traits (except for the effect of variety on sodium content) were significant. Evaluation of chlorophyll a and b content showed a decrease in the content of both chlorophyll a and b in both varieties, and this decrease was more noticeable at the tillering growth stage. The levels of catalase and superoxide dismutase enzymes increased in both Ehsan and Baharan varieties under the influence of salinity stress, and this increase was more considerable in Ehsan variety at the stemming stage. Sodium content also increased under salinity stress, but this increase was not significant in Baharan variety at the tillering stage and in Ehsan variety at the stemming stage. In contrast, the changes in potassium content due to salt stress were different in two varieties, so that the potassium level in Baharan showed a significant increase at both growth stages due to salinity stress, while in Ehsan it decreased significantly at tillering stage, but its change wasn’t significant at stemming stage. Proline levels also showed a significant increase under salinity stress conditions at both growth stages and in both varieties. In addition, the activity of both genes P5CS and P5CR also increased in both wheat varieties under salinity stress, indicating that there is a direct relationship between the changes of proline levels and the activity of genes involved in its biosynthesis pathway (i.e. P5CS and P5CR) under salinity stress conditions.
Conclusion
Evaluation of biochemical traits and gene expression in the studied two wheat varieties in the current research showed that Ehsan variety can be introduced as a salinity-tolerant cultivar and used in future breeding programs to increase salinity tolerance in wheat.
کلیدواژه‌ها [English]
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