Comparison Of Drought Stress And Re-watering Treatments On Adaptation Of Five F. Arundinacea Varieties At Early Growth Stage

As an excellent cool-season turfgrass with quick turf establishment, long green-period, good disease resistance and ornamental effects, Festuca arundinacea Scherb has been widely planted and considered to be the most important lawn plant. Under water stress, however, its ornamental effects will decrease and the Scherb will even die. Research indicates that drought stress is one of the most important factors restricting Festuca arundinacea Scherb’s growth and application. To plant Festuca arundinacea Scherb widely, maintain it scientifically, and meanwhile save water, it is of great significance to select out varieties with better qualities of drought resistance and growth and restoration after re-watering.By pot experiment, five F. arundinacea varieties of Greentreasure, Millennium, Houndog 6, Arada and Reward were respectively treated with normal-watering,15-day drought stress and 15-day re-watering treatment within 55 days. 1day before and every 5 days during the experiment, Fresh weight, dry weight, water content, seedling length, root length, number tiller, proline content, soluble sugar content, free amino acids content, malondialdehyde content, peroxidase activity, and root activity were measured and calculated by the method of membership function. The results are as follows.Plants with nomal-watering treatment were better than those under drought stress in fresh weight, dry weight, water content, seedling length, root length and number tiller. Under drought stress, except for fresh weight and water content, all the five Festuca arundinacea Scherb increased in dry weight, seedling length, root length and number tiller, the effect at 0-5 days being bigger than that at 10-15 days; fresh weight increased at 0-5 days, decreased at 10-15 days; water content decreased at 0-15 days. After re-watering, all increased in fresh weight, dry weight, water content, seedling length, root length and number tiller. The increase was different compared with that under drought stress:fresh weight increased the most, seedling length the least. At 15 d of drought stress and 15 d of re-watering, Millennium, Reward, Houndog 6, Greentreasure outgrew Arada.Under drought stress, all the five varieties were higher than those with with nomal-watering treatment in organic osmoregulation substances such as the content of soluble sugar (SS), proline (Pro) and free amino acids (FAA). Compared with the beginning of treatment, at 15 d under drought stress, all t increased in SS, Pro and FAA, with Pro increasing significantly more than SS and FAA. At 15 d after re-watering, the content of SS, Pro and FAA were all higher than those with normal-watering treatment; compared with 15 d under drought stress, re-watering led to the decrease of SS, Pro and FAA, Pro decreased significantly more than SS and FAA. The content of SS was higher than Pro and FAA in all the five varieties under drought stress and after re-watering.Compared with normal-watering, under drought stress, all the five varieties first increased then decreased in POD activity. All increased in MDA. At 15 d under drought stress, all were lower than those with normal-watering in POD but higher in MDA. During re-watering, all the five varieties increased in POD activity but decreased in MDA. At 15 d after re-watering, except for Arada, the other four were higher than those with normal-watering in POD and MDA. Under drought stress and after re-watering, Houndog 6 was the highest in POD activity and the lowest in MDA; while Arada was lowest in POD and the highest in MDA.Under drought stress, all the five varieties increased in root activity at 0-5d, the activity being higher than those with normal-watering; decreased at 5-15 d, the rate being different. After re-watering, all increased in root activity. At 15 d after re-watering, Except for Houndog 6, the other four were lower than those in root activity with normal-watering. The order of the five varieties from the highest to the lowest in root activity was Houndog 6, Greentreasure, Reward, Millennium, Arada.Dry weight, water content, seedling length, root length, number tiller, Pro, SS, FAA, MDA, POD and root activity were calculated by the method of membership function and comprehensively evaluated on the basis of principal component. The order of the five varieties from the highest to the lowest in drought resistance was Houndog 6 > Greentreasure> Millennium> Reward> Arada, while the order in growth and restoration after re-watering was Houndog 6> Greentreasure> Millennium> Reward> Arada.