Effects On Physiological Characteristics Of Miscanthus Sacchariflora (Maxim) Benth Under Water Stress

The ornamental grass is becoming fashionable things in recent years. Miscanthus sacchariflora (Maxim) Benth is perennial herb in Gramineae. Miscanthus sacchariflora (Maxim) Benth can create good palnt community landscape and it is also a potential ornamental grass. In this study Miscanthus sacchariflora (Maxim) Benth was measured in some different water conditions through PEG simulative drought pressure experiments, natural drought pressure experiments. We have studied the effect of drought stress simulated by PEG on seed and seeding of M. sacchariflroa. We have also studied on the effect of under drought stress on seeding of M. sacchariflroa in order to find out the adaptive condition of soil and water to M. sacchariflroa, then to clarify its water stress tolerant mechanism and provide theoretical and practical basis for the landscape application of M. sacchariflroa.This main experiment results are as follows:1. The condition of effects on M. sacchariflroa’s seed of the first harvest by PEG is not the same as that is stored one year. There ate inhibition on M. sacchariflroas seed of the first harvest by each concentration’s PEG. Effect on M. sacchariflroas seed of the first harvest by PEG is two-phase:low doses promote while high does inhibit. When PEG concentration is5%indexes of M. sacchariflroas seed of the first harvest hold a higher level. So the suitable inhibitive concertration of M. sacchariflroas seed o f the first harvest is5%.20%PEG has been beyond the tolerance range.2. The biggest effect on PEG stress of M. sacchariflroas seed of the first harvest is vital index, and the least affectivest is embryo length. The biggest effect on PEG s tress of M. sacchariflroas seed stored one year is germination rate, and the least affect ivest is embryo growth.3. Effect of PEG stress on physiological changes of M. sacchariflroas seeding is as follow:as the stress level increases the chlorophyll content declined, MDA content and H2O2content raised, ASA content, GSH content, SOD, POD, CAT, APX, G R, DHAR activity increased before decreasing. MDHAR activity did not change signifi cantly. As the drought stress rise, the chlorophyll content declined too. MDA content a nd H2O2content increase. But the antioxidang substances increased before decreasing.4. PEG stress and drought stress had an effect on pohtosynthesis of M. sacchariflr oa’s seeding. It also damage of membrane sustems by accumulated active oxygen whic h related with degree and time of stress. ASA, GSH, SOD, POD, CAT, APX, G R, DHAR could combined action to against damage.5. Chlorophyll content, MDA and H2O2content can be used as important evaluatio n indexes of M. sacchariflroa’s seedlings under drought stress6. National seedlings can stand mild-to-moderate stress (20%PEG) and mild-to-moderate natural drought stress of soil relative water content (60%) for long time. In a certain period of time (within24hours of PEG stress, within20d soil stress) seeding of M. sacchariflroa would also resistance PEG and natural soil drought stress.