The omission of second division gene (OSD1) gene plays a fundamental role in meiosis and is associated with 2n gamete formation in Arabidopsis thaliana. The objective of this work was to unravel the mechanisms leading to 2n pollen production, and isolate and analyze the expression patterns of OSD-like (OSDL) genes in carnation (Dianthus caryophyllus). We found an absence of the second meiotic division caused the formation of 2n pollen. Three homoeologous genes were cloned and labeled as OSDLa, OSDLb, and OSDLc in a diploid carnation. The cDNAs were 1180 bp for OSDLa, 1288 bp for OSDLb, and 971 bp for OSDLc. A strong similarity was found between the amino sequences of OSDLb and OSDLc. An evident feature of OSDLs proteins is the presence of D-box and MR-tail domains; however, the GxEN/KEN-box domain, which is distinct among the other plant proteins was absent. Quantitative real time polymerase chain reaction (qRT-PCR) analysis showed that OSDL genes maintain continuous expression in buds and other tissues. OSDLa has the highest expression in buds of 1.1–1.2 cm long (stage 2), and OSDLb has a high level of expression in buds of 0.9–1.0 cm long (stage 1) and stage 2 buds and ovary tissues in three carnation cultivars. The expression level of OSDLc was highest in ovaries. These expression patterns strongly suggest that OSDLs in carnation involve male meiosis and ovary development. These findings can have potential applications in fundamental polyploidization research and plant breeding programs in carnation.
Luculia pinceana is a potential cut flower because of its long-term blooming inflorescences and charming fragrance. However, its narrow distribution area and unexplored wild status severely restrict its applications, thus leading to the scientific research of cut L. pinceana flowers. To our knowledge, there is no available published information about the postharvest fresh-keeping of L. pinceana. During this study, the cut flowers of L. pinceana were tested using nine preservatives with different concentrations of sucrose and 8-hydroxyquinoline (8-HQ) to evaluate the fresh-keeping effects. Through the investigation and analysis of vase life, bud opening and abortion rate, water balance, malonaldehyde (MDA) content, and peroxidase (POD) activity, we selected and identified the best vase solution for cut L. pinceana flowers. The results suggested that the preservative of 1% sucrose and 100 mg/L 8-HQ could significantly prolong the vase life of cut L. pinceana flower up to 9 days compared with water control. This solution positively affects flower bud blooming, delays flower senescence, improves the water balance, inhibits the MDA accumulation, and increases POD activity. Therefore, this preservative is suitable for the fresh-keeping of cut L. pinceana flowers. Our study is the first to report the effects of preservatives on cut L. pinceana flower. The results showed that the low-sugar-containing (1% sugar) preservatives can effectively improve the ornamental quality of fresh flowers and demonstrated that the postharvest fresh-keeping of L. pinceana requires low sugar and is insensitive to microorganisms.