This study explored the changes in senescence patterns and vase life of cut roses grown in summer and autumn, aiming to identify the relationship between harvest seasons and flower longevity. We analyzed gene expression profiles associated with lignin, pectin, ethylene, auxin, and sucrose transport to understand the molecular mechanisms underlying senescence symptoms, such as the bent neck, petal abscission, and petal wilting in cut rose flowers. Our results revealed season-dependent occurrences of bent neck and petal abscission, with higher incidence rates in autumn-harvested rose flowers. These increases in bent neck and petal abscission contributed to a shortened vase life for the cut flowers. Gene expression analysis indicated that elevated levels of ethylene biosynthesis genes and reduced expression of lignin, pectin biosynthesis, auxin response factor, and sucrose transport genes accelerated the increased senescence symptoms. Notably, the incidence rates of the bent neck were highly negatively correlated with the transcript levels of key genes involved in lignin and pectin biosynthesis, RhPRXPX and RhGAUT1, in pedicels. These findings contribute to our understanding of the molecular factors influencing the mechanical strength of flower pedicels and provide insights for postharvest strategies to enhance the ornamental value of cut flowers across seasons.

The effects of light intensity and external sucrose on the vase life of cut roses were estimated by monitoring the net photosynthesis and chlorophyll fluorescence. Cut flowers were held under different light intensities 10 (L10) or 50 (L50) μmol‧m-2‧s-1 with or without treatment with external sucrose. We found substantial differences in stomatal conductance, photosynthesis rate, photosystem II (PSII) quantum efficiencies, specific fluxes, and vase life of the cut flowers when exposed to different light intensities. Light intensity at 50 μmol‧m-2‧s-1 increased photosynthesis capacity, thus delaying petal senescence and extending the vase life of cut flowers. L50 flowers maintained a high photosynthetic rate by reducing heat dissipation (DI0/RC) and increasing electron transport (ET0/TR0 and ET0/ABS) in the electron transport chain of the photosynthesis apparatus. The application of external sucrose extended the vase life of cut flowers by improving water balance and sustaining turgor pressure in the petals of the cut flowers. The net rate of photosynthesis of the cut flowers was increased by higher light intensity; however, it was not affected by the application of external sucrose. Our results indicate that the application of external sucrose is necessary to improve the longevity of cut flowers when endogenous sucrose production by photosynthesis is insufficient under low light conditions during the postharvest period. In addition, our results revealed that most of the photosynthetic parameters were significantly correlated with the vase life of cut rose flowers. Moreover, the relation between the rate of photosynthesis and chlorophyll fluorescence parameters indicates that the rise from the basic dark-adapted fluorescence yield to the maximum (OJIP transient) method can be used as a tool for the evaluation and prediction of the photosynthesis rate in cut flowers.

Gray mold is caused by the fungal pathogen Botrytis cinerea (B. cinerea), a commercially damaging disease of rose flowers. The infection of this necrotrophic fungal pathogen is one of the most important reason that rose flower is rejected by consumers and importers, leading to economic losses. The gray mold disease influences rose flowers through cultivation and distribution in the greenhouse, storage, transport, and market. Environmental conditions and genetic factors are two primary factors that affect the development of gray mold in the flowers during pre- and postharvest stages. However, the interaction between B. cinerea and rose flowers at the molecular level has not been well studied to date. Despite the multiple studies conducted over the past decades, breeding flowers that have resistance to B. cinerea has not been successful in roses. Furthermore, the mechanism underlying tolerance to gray mold is under-investigated and poorly understood in roses. The most popular current control strategies against B. cinerea in roses are pre- and postharvest fungicides, but they are generally expensive, ineffective, and polluted. In this review, we summarized the nature of B. cinerea in plants and discussed the current control strategies of gray mold disease in rose flowers, such as radiation, resistance inducer, chemical and biological control. In addition, we propose an approach for reducing B. cinerea infection in rose flowers by using ethylene antagonists.

Ethylene-mediated premature floral senescence influences the postharvest quality and longevity of rose flowers. In recent years, studies have unveiled the action of ethylene during the development and senescence of rose flowers. However, despite the evidence that ethylene is highly produced in ethylene-sensitive roses, there is not always a direct interrelationship between ethylene sensitivity and rose flower longevity. In addition, ethylene sensitivity and ethylene-related gene expressions in roses are still not clearly understood. In this review, we summarized and discussed ethylene synthesis and sensitivity, role of ethylene-related genes, and impacts of ethylene on the postharvest quality of cut roses. By combining the mechanism of ethylene biosynthesis and signaling with ethylene sensitivity, we also highlighted the potential use of ethylene inhibitors for ethylene control and to improve the postharvest quality of cut rose flowers. We believe that this review will provide sufficient information about ethylene biology in rose flowers and contribute in developing effective methods to extend the postharvest life of roses by preventing ethylene damage.

Botrytis cinerea is a necrotrophic pathogen that significantly reduced the postharvest quality and longevity of cut roses. The aim of this study was to examine the effects of nano silver, sodium hypochlorite (NaOCl), and salicylic acid on B. cinerea infection in cut rose flowers. Cut ‘Revival’ roses were treated with nano silver, NaOCl, salicylic acid, and distilled water, and simultaneously held in the solutions. Subsequently, the cut flowers were sprayed with B. cinerea solution and held under export conditions for 4 days. The results showed that nano silver was the most effective treatment in suppressing B. cinerea growth in cut roses during vase life. Nano silver effectively extended the vase life of cut roses by 2.3 days, compared with non-treated flowers. The addition of nano silver also enhanced water uptake and sustained the water balance and fresh weight of the cut rose flowers. Our results indicated that nano silver is an effective treatment solution to inhibit B. cinerea infection and improve postharvest quality and longevity of cut rose flowers for export.

Cut roses often have a short vase life due to water stress and ethylene damage under unfavorable postharvest conditions. In this study, we investigated the effect of various pretreatment solutions on the vase life and postharvest quality of the cut rose cultivar ‘Jinny’ (Rosa hybrida L.). Cut roses were pretreated with eight different preservative solutions for 10 hours: aluminum sulfate (AS), Chrysal (CHR), FloraLife (FLR), lysosome (LYS), MS-1 (MS1), MS-2 (MS2), silver n itrate ( SN), a nd s ilver t hiosulfate ( STS). We found that pretreatment with all solutions except LYS prolonged the vase life and improved the postharvest quality of the cut roses. Among these, STS was the most effective pretreatment solution, significantly extending the vase life from 11.8 days (control) to 19.9 days, retaining the initial fresh weight and a positive water balance for longer, and inhibiting microbial growth in the vase. STS also enhanced the water uptake rate, and maintained the high chlorophyll and soluble sucrose contents in the leaves of the cut rose flowers. In addition, we found that MS1 and MS2, which are natural plant extracts, had strong antimicrobial effects and consequently prolonged the vase life of cut roses by more than 4 days compared with the control. Therefore, MS1 and MS2 can be considered as alternative preservatives in the cut flower industry.

국화(Chrysanthemum morifolium)는 다양한 화색과 화 형 때문에 세계에서 가장 인기 있는 관상식물 중 하나 로서 절화, 분화 및 화단용 등 다양한 형태의 국화에 대 한 요구가 증가하고 있다. 본 연구는 SSR 마커를 이용하 여 국화 60 품종에 대한 유전적 유연관계를 조사하고, 군 집분석결과와 표현형간의 상관관계를 조사하기 위하여 수 행하였다. 표현형질 38개를 이용한 군집분석 결과, 대부 분의 국화 품종들이 화형과 화색에 따라 8개의 그룹으 로 분류되는 것으로 나타났다. 본 연구에서 사용된 150 개의 SSR 프라이머는 기존연구에서 보고된 62개와 C. nankingense의 unigene 염기서열 및 C. morifolium의 EST 염기서열로부터 디자인한 88개로 구성되었다. 국화 8품종에 대한 다형성 및 banding pattern 결과를 토대로 하여 국화 60 품종의 DNA 증폭에 사용할 13개의 SSR 마커를 최종 선발하였다. SSR 마커를 이용하여 군집분석을 행한 결과, phylogenetic tree에서 국화 60 품종 전 부가 화색에 따라서 6개의 그룹으로 분류되는 것을 확 인할 수 있었다. Phylogenetic tree와 화색간의 상관관계 를 조사하기 위하여 화색을 종속변수, SSR 마커를 독립 변수로 설정한 다중회귀분석(MRA)을 행하였다. MRA 결 과는 화색과 SSR 마커간에 통계적 유의성이 높은 상관 관계(r2 = 0.903, P < 0.05)를 나타냈다. 본 연구결과는 경 쟁력 있는 국화 신품종 육종을 위한 데이터로 활용될 수 있을 것으로 생각된다.

Chrysanthemum (Chrysanthemum morifolium) is one of the most popular ornamental species in the world due to the great diversity of inflorescence form and color. There has been increasing demands for various types of chrysanthemums, such as cut flowers, potted plants and bedding plants. However, the genomic studies of this species have been not extensively conducted relative to other ornamental species due to high levels of polyploidy (2n = 4x =36 or 2n = 6x = 54) and heterozygosity as well as large genome size. In this work, we developed a molecular tool for cultivar identification using simple sequence repeats (SSRs) and investigated genetic diversity in 127 chrysanthemum cultivars. Of the 150 SSR primer pairs tested in this study, 62 primers were obtained from previous studies, while 88 primers were designed using the unigene sequences of C. nankingense and the Expressed Sequence Tag (EST) sequences of C. morifolium in the NCBI database. Thirty SSR primers were selected based on polymorphism and banding patterns in a subset of 8 cultivars and used to amplify the DNA of 127 chrysanthemum cultivars. The UPGMA dendrogram based on these 30 SSR markers showed that most of chrysanthemum cultivars were divided into five clusters. These results will benefit chrysanthemum research community to develop elite cultivars.