Physiological Responses Of Miscanthus Sinensis Seed And Seedling To Drought Stress

Miscanthus sinensis blongs to Poaceae and it is perennial herbaceous plants of C4. It gets the favour of western developed countries because of its rapid growth, high biomass,and wide suitability, and it is chosen as one of the most potential energy plants by western countries. At the same time, it plays an increasingly important role in the city as a new ornamental grass. By studying the influence of PEG stress on germination characteristic of Miscanthus sinensis seed, and researching the influence of PEG drought stress and soil drought stress on physiological property of Miscanthus sinensis seeding, this research provides theoretical support for agricultural production and urban landscaping of drought resistant plants, laies the foundation for application in landscaping, and improves the diversity of urban plants. By studying the influence of PEG stress on germination characteristic of Miscanthus sinensis seed, and researching the influence of PEG drought stress and soil drought stress on physiological property of Miscanthus sinensis seeding, the results show:Germination index、vigor index and plumule of Miscanthus sinensis are higher but no significant role in promoting than CK under the condition of low concentration PEG, although the radicle is significantly higher than CK; High concentration PEG has significant inhibitory effect on seed germination and the growth of radicle and plumule of Miscanthus sinensis; With the increase of PEG concentration, GDRI of Miscanthus sinensis is on the decline, middle grade at15%PEG concentration, medial lethal concentration and limiting concentration are20%and25%; Storage time has a certain influence on germination of Miscanthus sinensis seed.As the extension of PEG stress time, MDA and relative electric conductivity increase, and SOD、POD、CAT、APX、GR、ASA、GSH rise firstly and then decrease, but in the different condition of PEG congentration stress, the change of each index are not identical. In the beginning of PEG stress, Miscanthus sinensis seedings avoid oxidative stress damage by increasing SOD、POD、CAT、APX、GR activity and ASA、GSH content; With the increase of stress time, indexes of low concentration (<10%) are all maintained similar to CK level, although indexes of high concentration are significant different with CK group, and these show that, Miscanthus sinensis seedings can endure damage under20%PEG stress, but Miscanthus sinensis seedings will cause severe drought stress and even die if the PEG concentration are more than20%.Before re-watering under soil drought stress, MDA and relative electric conductivity increase-and SOD、POD、CAT、APX、GR rise firstly and then decrease; after re-watering, MDA and relative electric conductivity increase slowly, APX and GR start to pick up, SOD、 POD、CAT、ASA、GSH slow down the peace of decline. Treatment one (re-watering after ten days) cause less damage to Miscanthus sinensis seedings; Treatment two need sometime to recover and cause great damage; Seedings of treatment three died after20days soil drought stress; these show that, limit time of Miscanthus sinensis seedings enduring soil drought stress is20days, and the best time to water is10-15days.