Studies On The Physiology Of Chilling-resistantce And Its Molecular Mechanih In Tall Fecscue Turfgrass

The adaptation to harmful environment of plant not only be controlled by the genes of phylogeny but also be restricted by the photosynthetic physiological ecology of individual development. Study on the adaptability of low temperature could improve the quality of cold season lawn. and enlarge the culture area. On the other hand the excellent chilling resistant genes of cold season lawn have development value, wich provide new ways for complete solving the problem of turning yellow of cold season turfgrass in winterThis experiment was consisted of three steps :firstly, different low temperature stresses of five Festuca species, physiological index was determined, mainly including enzymes systems,hormones,chlorophyll,soluble carbohydrate and proteins and so on. Research shows that five Festuca species showed different extent changs on every physiological indexes, and the physiological index would get an increase with the temperature continuously decreasing. Because of the difference of cold - resistance the various index have difference. To compare the structure Houndog 5 and Southern Gold have a strong cold resistance, midsummer and night-shining jewel different low, fine combination is the poorest. In the second stage, selecte Houndog 5 with the highest cold resistance, after enduring in the frost of 5℃, found that with the treating time prolongs, the contents of SOD,POD,MDA,Free Proline and so on increase steadily, up to 8h day the extent of increase was taking slow. It is suggested that after enduring in the frost in 6 days the frost resistance the strongest in the tillering stage.In addition, because of the limitations of research, there have many uncertainty understanding,which reflected the complication of mechanisms in plant cold resistance. This must continue to research at molecular level, increasing the utilization value of turf grass. The expression of cold resistance gene of plant is induced differentially under specific environments. Furthermore, become a new ability of the cold resistance (that is gene→protein(enzyme)→metabolism→function of physiology). Thirdly, the investigation was conducted to detect the related gene expression profiles in Houndog 5 exposed to cold resistance using suppression subtractive hybridization (SSH) method. A total of 36 ESTs from SSH-cDNA library were sequenced, and all of the sequences of inserted fragments were analyzed with the aid of bioinformatics. Twenty-four genes were sorted into five groups such as plant resistance to the environmental stress, transduction of signal, photosynthesis, plant growth and cell cycle regulation, protein synthesis and degradation, which were involved in the pathways of the environmental stress in Houndog 5, wich further proved that the cold resistance of plant is controlled by polygenes.