Study On Cold Resistance Mechanism Under Nitrogen Of Tall Fescue Turfgrass

Tall fescues have long green and stronger cold resistance, which is very popular and widely applied in excessive temperature area of the Yangtze river. It is not too low temperatures in winter in this area, the average temperature is 0℃above in January, but due to various reasons, many lawns are yellow and dormant in winter. This experiment research tall fescues physiological and biochemical characteristics under low-temperature and the physiological and biochemical responses in plant after N treatment, the purpose is to find physiological mechanism of cold resistance of tall fescues, to provide theoretical basis in winter management of cool-season turf grass in Yangtze river area. The results showed that:1. An experiment was conducted to study the physiological and biochemical characteristics of different positions of leaf during over-wintering stage with the festuca variety of arundinacea. The results showed that contents of chlorophyll, soluble protein, AsA, total N and K, and activity of anti-oxidative enzyme in upper part of the leaf were significantly lower than other parts, but contents of GSH and MDA were higher than other parts. During the over-wintering stage, soluble protein, total N and K contents in different leaf positions had no obvious changes, while chlorophyll and total P contents first decreased and then increased, and activities of SOD and POD and content of MDA increased first and then decreased.2. Effects of different nitrogen concentrations on physiological and biochemical characteristics cultivar of tall fescue grown under 5℃/0℃low temperature were studied in a pot culture experiment. The results show that low temperature stress has brought a degree of damage to tall fescue growth, and injuries were aggravated with increasing stress time. Biomass, chlorophyll content, soluble protein content and total nitrogen, phosphorus and potassium of the same nitrogen concentrations were higher at room temperature than the low temperature. Under low temperature stress, when the nitrogen concentration was15mmol/L. it may effectively relieved the damage, which showed the activites of antioxidant enzyme system and increased activity of non-enzyme system increased. MDA content was lower and biomass. chlorophyll and soluble protein content and total nitrogen, phosphorus and potassium content was significantly higher in no nitrogen and high nitrogen treatment, making tall fescue well under stress in low temperature.3. This experiment was conducted to study the physiological and biochemical characteristics with different N levels during over-wintering and returning green stage with the tall festuca variety of expedition. The results showed that:many physiological index were significant difference during the over-wintering stage with different N levels. MDA Content of high nitrogen and non nitrogen treatment was significant high than others. N20 treatment have higher water concentration, which is not beneficial to over winter safely, and spindling after returning green stage, No treatment returning green unnormal.5 mmol/L of nitrogen level, tall fescue keep good luster in over-wintering stage, activity of antioxidant enzymes was increase, soluble protein was decrease first and then increase, content of AsA was decrease, MDA content keep lower, provide guarantee for over-wintering and returning green.