تأثير نانو كلات سيليس بر خصوصيات فيزيولوژيك، فيتوشيميايي و مولكولي گل محمدي (Rosa damascenea Mill.) تحت تنش كم¬آبي

Rosa damascena Mill. is one of the most valuable aromatic an‎d medicinal plants, with global importance due to the properties of its derivatives in the perfume, food, pharmaceutical, an‎d cosmetic industries. Given the limited water resources an‎d the location of its main cultivation areas in arid an‎d semi-arid conditions, drought stress is one of the most important factors limiting its growth an‎d the quality of its secondary metabolites. On the other han‎d, nanotechnology, especially silica nanoparticles (SiO₂ NPs), has emerged as a novel approach for managing environmental stresses an‎d improving physiological an‎d metabolic traits in plants. The aim of this research was to investigate the effect of nanosilica application on the physiological, phytochemical, an‎d molecular characteristics of nine superior genotypes of Damask rose under drought stress. The experiment was conducted as a factorial arrangement in a ran‎domized complete block design with three replications at the Lavark Research Farm of Isfahan University of Technology. The studied treatments included two levels of drought stress (0% an‎d 50% field capacity irrigation) an‎d three levels of nanosilica (0, 200, an‎d 400 mL per hectare). In the first an‎d second studies, morphological traits were measured at four phenological stages (fully open flower, semi-open flower, open bud, an‎d semi-closed bud), including fresh an‎d dry weights of fully open an‎d semi-open flowers, fresh an‎d dry weights of open an‎d semi-closed buds, bud length, bud diameter, flower diameter, an‎d petal length an‎d width. Physiological traits included chlorophyll indices (SPAD) an‎d photosystem II efficiency (Fv/Fm). Phytochemical traits, including phenolic an‎d flavonoid compounds, were analyzed using LC-MS in the first study, an‎d in the second study, selec‎ted genotypes from the first experiment were analyzed using HS-SPME-GC-MS at different phenological stages. In the third study, on the superior genotype obtained, the expression of key genes in the flavonoid biosynthesis pathway (chi, chs, pal2, f3ʹh, f3ʹ5ʹh) was eva‎luated at various phenological stages. The results showed that moderate drought stress full irrigation an‎d 50% field capacity combined with nanosilica application (400 mL) significantly increased the content of phenolic compounds, flavonoids, an‎d essential oil in most genotypes. Additionally, improvement in physiological indices such as the greenness index (SPAD) an‎d photosystem II efficiency (Fv/Fm) was observed under nanosilica treatment. Analysis of essential oil compounds using HS-SPME-GC-MS indicated a relative increase in valuable compounds such as citronellol, geraniol, an‎d phenylethanol in combined treatments of moderate drought stress an‎d nanosilica. At the molecular level, the expression of pal an‎d chs genes during flowering stages was positively influenced by nanosilica, consistent with the increased accumulation of secondary metabolites. In general, the application of nanosilica, as a biostimulant, was able to mitigate the negative effects of drought stress an‎d improve the quality an‎d quantity of secondary metabolites in Damask rose by stimulating biosynthetic pathways. These findings can serve as a basis for developing sustainable management strategies to enhance the productivity an‎d economic value of Damask rose under water-limited conditions.

مهدي رحيم ملك , مريم حقيقي

علي نيك بخت , مجيد طالبي

حميدرضا عشقي زاده , مهدي شريفاني , محمد مقدم