A Brief Research On The Mechanism How MET Affects The Freesia Plant Type

The impacts of plant growth retardants are proved to be temporary and limited. It isbelieved that only plant genotype improvement can fundamentally optimize the physiologicalmetabolism through the regulation of endogenous hormones, which can further breedminiature flowering plants with more ornamental value.This research studies the influence of paclobutrazol on Freesia plant type, and MSAPtechnology was applied to detect DNA methylation level in dwarf plants. The results showedthat paclobutrazol significantly influenced Freesia carbon and nitrogen metabolism, especiallyin organic acids and potassium metabolism. After the inducement of MET, Freesia bodypotassium content was significantly increased, and the intermediates of citric acid cycle waschanged. With MET, the leaf malic acid content was reduced, the root malic acid content wasincreased, the succinic acid content of roots and leaves was increased, the leaf citric acidcontent was increased and the root citric acid content was decreased. These results suggestthat paclobutrazol have significant impact on the Freesia respiration (TCA cycle), as well asthe absorption and transportation of plant potassium. As energy metabolism, hormonalregulation and nutrient transportation are inevitably involved in the dwarf plant, Paclobutrazolon the metabolism of interference may be related to the dwarf phenotype. However, theprecise relationship between them is not yet clear and some further studies are demanded.One possible explanation is that MET may trigger the epigenetic regulation mechanism.MET is an effective method to produce dwarf Freesia, and the dwarfing mechanismcould be multi-faceted. Our results confirmed that paclobutrazol may change many metabolicprocesses of Freesia, such as nitrogen metabolism, the accumulation of mineral ions. Inaddition, we detected that MET could induce variation of methylation patterns in Freesia. Aswe all know, DNA methylation is one of the most important modes in regulating geneexpression and metabolic processes. Our results imply that the impact of paclobutrazol onplant height and metabolism of Freesia may be resulted from epigenetic modifications,. butthe exact mechanism still needs further study..