Effects Of Different Irrigation Lower Limit Synchronization With ABA On Green Period , Appearance Quality Of Lawn And Cold-resistance Of Tall Fescue

The pot experiment was conducted to study the effects of 0mg/L,5mg/L,15mg/L,30mg/L abscisic acid(ABA)on membrane permeability proline content carbohydrate metabolism in tall fescue under low temperature stress,which provided evidence for ABA apply to sports turf ground in north. Evaluated the effect on green period and cold-resistance of tall fescue,which was treated with different irrigation minima(80%FC,70%FC,60%FC,50%FC) in combinated with ABA,and the interaction of irrigation and ABA was analyzed in late autumn to early winter.The results showed that as follows:1.Tall fescue under the low temperature in winter,led to decrease in appearance quality of lawn,SOD,CAT activity;enhance the content of soluble sugar,free praline and malondialdehyde (MDA);the POD activity increased at first and then des decreased .2.Foliar Spraying ABA can effectively enhance greenness and growth of tall fescue before the winter, increased the soluble sugar and free proline content, superoxide dismutase (SOD) , peroxidase (POD) and catalase (CAT) activity were stronger, decreased the relative electric conductivity and the content of malondialdehyde (MDA).Among all ABA experimental treatments, A2 (15mg/L) showed the best effect on cold-resistance, Tall fescue had the lowest peroxidation degree of cell membrane system, the highest content of osmotic regulation matter and the highest activity of active-oxygen-scavenging enzyme.3.Tall fescue treated with the irrigation low limit of 80% and 70% of field capacity (FC) in combinated with ABA maintained a dramatically higher greenness,growth,uniformity,density, leaf relative water content,POD,CAT and SOD activities,chlorophyll,soluble sugar and free proline content,had lower MDA content and electrolyte leakage under the low temperature,showed the best effect on cold-resistance.4.Compared with the irrigation minima of 50% of field capacity ,the green period of tall fescue could be prolonged32day,28 day when treated with the irrigation minima of 80%,70% of field capacity in combinated with ABA. By comprehensive consideration of water saving and water use efficiency, Results from this study show that the appropriate management combinations for tall fescue is 70%of field water capacity in combinated with ABA,which not only make full use of water resources but also effective prlong green period in late autumn to early winter.