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Chrysanthemum (Dendranthema grandiflorum (Ramat.) Kitamura cv. Pattriot) is one of the most important and marketable cut flowers in the world. However, a relatively limited vase life reduces its marketability. The aim of this study was to evaluate the efficacy of salicylic acid (SA) and citric acid (CA) in extending the vase life of chrysanthemum flowers. Therefore, a factorial experiment based on completely randomized design with SA at (0, 100, 200, 300 ppm) and CA at (0, 100, 200 ppm) with 3 replicates and 3 samples (individual flowers) for each replicate, was conducted. Applying SA and CA increased vase life, petal water content (%), initial fresh weight (%) and marketability, significantly. SA treatments increased leaf relative water content (RWC), petal water content (%) and initial fresh weight (%) by 49, 73 and 23 %, compared to the controls, respectively. The highest vase life (21.77 days) was observed for the treatments of SA (300 ppm). The significant increase (300%) in vase life is considered to be due to plant regulating and anti-stress properties of SA and CA. According to the results of this experiment, SA and CA as natural, cheap, safe and biodegradable compounds are suitable alternatives for conventional chemical treatments in order to prolong vase life of cut flowers of chrysanthemum. Commercialization of these compounds for optimum formulations needs further experiments.

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 Two experiments were performed for in vitro establishment, proliferation and shoot growth in axillary bud explants of Sebri pear cultivar. In the first experiment, the effect of different concentrations of IBA(Indole-3-butyric acid) on explants’ establishment was evaluated. In a second experiment, the influence of several combinations of PGRs (Plant growth regulators)on shoot proliferation and shoot growth was investigated. IBA at 0 and 0.1 mg L^-1 concentration led to successful bud establishment. At higher IBA concentrations, callus was induced, but fewer explants were successfully initiated. BAP increased shoot proliferation, while TDZ(Phenyl-N'-(1, 2, 3-thiadiazol-5-yl) urea) did not show any effect on shoot proliferation. BAP, at 3 mg L^-1 was more effective than 2 mg L^-1 on the number of proliferated shoots. Maximum shoot length was obtained for the medium containing BAP(6-benzylaminopurine) (2.0 and 3.0 mg L^-1)+IBA (0.1 mg L^-1) and BAP (2.0 and 3.0 mg L^-1)+IBA (0.1 mg L^-1)+GA₃ (0.5 mg L^-1). IBA in BAP combinations induced lateral bud swelling, while GA₃ (Gibberelic acid) inhibited it. Maximum leaf number was obtained for MS medium with 2.0 mg L^-1 TDZ and 0.5 mg L^-1 GA₃. Moreover, medium supplemented with 2.0 mg L^-1 BAP+IBA (0.1 mg L^-1)+GA₃ (0.5 mg L^-1) and 2.0 mg L^-1 TDZ+GA₃ (0.5 mg L^-1)produced maximum shoot length. Vegetative growth habit varied with different combinations and BAP concentrations, being the highest in BAP (2.0 mg L^-1)+IBA (0.1 mg L^-1) treatment. The combination of BAP at 2 mg L^-1 and 0.5 mg L^-1 of GA₃ is finally recommended for a proliferation of Sebri pear cultivar.

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The present study was carried out to investigate biochemical, morphological, and physiological processes involved in the adaptive processes of cut roses grown in arching and high-rack culture systems under water deficit condition. Rose plants ‘Club-Nika’ were subjected to three water regimes [control (100% of irrigation needs), moderate water stress (75%), and severe water stress (50%)] factorially combined with two training systems defined as arching and high-rack systems. Water deficit significantly reduced morphological and qualitative traits as well as water relations of cut roses. Water deficit significantly reduced Net CO₂ assimilation rate (P_N), transpiration rate (E), and stomatal conductance (g_s), whereas it did not affect Water Use Efficiency (WUEi) and intercellular CO₂ concentration (C_i). Surprisingly, water deficit did not affect chlorophyll content [chl a, chl b and total chl (a + b)] and proline accumulation of leaves. Considering the lack of change in intercellular CO₂ concentration, it seems likely that both stomatal closure and metabolic impairment limit photosynthetic CO₂ assimilation under water deficit. Regardless of irrigation regimes, rose plants trained with high-rack culture system showed a superiority for most of the qualitative and quantitative attributes compared to those trained with arching system. The high-rack system resulted in 60% higher extra-quality stems (> 60 cm) compared with the plants trained with arching. It can be concluded that cut roses respond to water deficit through adaptive changes in physiological and morphological levels to reduce water loss without any negative impact at biochemical level.
 

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Lower winter temperatures may negatively affect winter survival by preventing maximum cold acclimation before freezing temperatures. The process of cold acclimation requires adaptation to both light and low temperatures, depending on the duration of exposure. Accordingly, research is needed to identify strategies to promote cold acclimation and increase freezing tolerance. Therefore, this experiment was conducted to investigate whether a shorter or more extended preconditioning cold treatment can improve the cold hardiness of hollyhock and its threshold of winter hardiness. The results showed that both 14 (CP₁) and 28 days of Cold Preconditioning (CP₂) decreased electrolyte loss, increased the activity of SOD, CAT, and APX enzymes, inhibited accumulation of Hydrogen peroxide (H₂O₂), and delayed the increase of Malondialdehyde (MDA) content, while non-acclimated plants experienced a decrease in MDA. No difference was observed in antioxidant activity and photosynthetic parameters between CP₁ and CP₂. Although proline and water-soluble sugar contents were higher in plants subjected to 28 days of cold preconditioning than in those treated for 14 days, no significant difference was found in survival percentage. Low temperatures decreased photosynthetic parameters, while increasing leaf contents of Abscisic Acid (ABA) and phenolic. The results suggested that 14-day cold preconditioning could be used to increase cold tolerance for non-acclimated hollyhocks to grow in the field at -4°C.