نوع مقاله : مقاله کامل علمی پژوهشی
نویسندگان
1 دانشجوی دکترای فیزیولوژی تولید و پس از برداشت گیاهان باغبانی ، گروه باغبانی، دانشکده تولید گیاهی، دانشگاه علوم کشاورزی و منابع
2 دانشگاه علوم کشاورزی و منابع طبیعی گرگان
3 استادیار گروه علوم باغبانی، دانشکده علوم زراعی، دانشگاه علوم کشاورزی و منابع طبیعی ساری، ساری، ایران.
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Strawberry (Fragaria × ananassa Duch.) is one of the most important horticultural crops, valued for its high content of bioactive compounds such as anthocyanins, phenolics, and vitamin C, which contribute to its high nutritional quality. However, its high sensitivity to salinity stress significantly reduces growth, yield, and fruit quality. The use of biostimulants such as chitosan and sodium nitroprusside (SNP), as a nitric oxide donor, has emerged as an effective approach to mitigate the adverse effects of salinity and to enhance physiological and biochemical responses in plants. This study aimed to evaluate the individual and combined effects of chitosan and SNP on the quantitative and qualitative traits of strawberry fruits under salinity stress. The experiment was conducted in a factorial arrangement based on a completely randomized design with three replications at Sari Agricultural Sciences and Natural Resources University greenhouse. The first factor was salinity at three levels (0, 30, and 60 mM NaCl) that around 0, 3 and 6 ds.m-1 respectively, and the second factor was biostimulant treatment at five levels (control, SNP at 50 and 100 µM, and chitosan at 0.25 and 0.5 g L⁻¹). Treatments were applied to two strawberry cultivars (‘Camarosa’ and ‘Sabrina’) through foliar spraying at three stages: two weeks before salinity imposition, at the onset of stress, and two weeks after. Results showed that increasing salinity from 0 to 60 mM significantly reduced fruit weight (by 26.8%), fruit length (18.3%), TSS (22.5%), and vitamin C content (30.7%). In contrast, the application of biostimulants improved many of these attributes. Foliar application of 0.25 g L⁻¹ chitosan increased total phenolic content from 161.3 to 217.9 mg GAE 100 g⁻¹ FW and total anthocyanins from 28.5 to 37.4 mg C3G 100 g⁻¹ FW. In Camarosa cultivar, application of 50 µM SNP under 60mM salinity increased vitamin C content from 467.26 to 1026.9 mg 100 g⁻¹ FW and enhanced fruit firmness compared with the control. Although in sabrina cultivar, 0.5% chitosan under severe salinity(60mM) showed maximum vitamin C . Almost traits showed a significant salinity × biostimulant interaction. In ‘Camarosa’, 0.25% chitosan under moderate salinity (30 mM) produced the highest TSS (8.9 °Brix) and TA (0.93%), whereas 100 µM SNP under severe salinity (60 mM) maintained the highest fruit weight (13.2 g) and firmness (1.83 N). In ‘Sabrina’, both chitosan concentrations significantly enhanced phenolic and anthocyanin contents, while the effect of SNP was more limited. Overall, salinity stress had pronounced negative effects on fruit yield and quality, but foliar application of chitosan and sodium nitroprusside substantially mitigated these impacts. Chitosan improved fruit quality mainly through the enhancement of secondary metabolites and water balance, while SNP acted by regulating antioxidant cycles and ionic homeostasis. The ‘Camarosa’ cultivar compared to Sabrina, with enhancement weight and firmness fruit and highest level vitamin C under salinity stress, highest tolerance and effective reply to elicitor treatments.
کلیدواژهها [English]
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