Effects Of Soil Drought Stress On The Growth And Physiological And Biochemical Reaction In Fiber Herbaceous Energy Plants

Fiber herbaceous energy plants have a wide distribution in our country, they are rich in materials such as cellulose and hemicellulose, are regarded as a kind of promising prospects of alternative energy resources, at the same time can increase the amount of soil carbon sequestration, realize the drought marginal land management, ecological restoration, improve the ecological environment of local region, has been carried out widely in Europe and the cultivation and application and have extensive cultivation and application in Europe and the U.S. In order to provide scientific theory basis about cultivtionin management of energy plants in arid, semiarid land, this experiment by adopting the potted-seedling and weighing method to control soil moisture, studied the impact of soil water treatment of80%, Expressed in CK and40%, Expressed in MS,(60%of field maximum moisture capacity for mild stress treatment,20%of field maximum moisture capacity to treat severe drought stress), of field maximum moisture capacity on21kinds of fiber herbaceous energy plants (12kinds of Panicum virgatum L. and9kinds of Miscanthus) Growth and Physiological and Biochemical, and last used principal component analysis and subordinate function analysis evaluating the drought resistance of21kinds of fiber herbaceous energy plants.The experimental research conclusions are as follows:1. Compared to the ck, moderate drought stress significantly inhibited the growth of21kinds of fiber herbaceous energy plants, Morphology and growth indicators have taken place significant changes. Among them, the changes of12kinds of Panicum virgatum plants morphology and growth indicators are:plant height, aboveground biomass were declined in different degree, underground biomass, root-shoot ratio and root length were increased to some extent; the changes of9kinds of Miscanthus plants morphology and growth indicators are:plant height, aboveground biomass and total biomass were decreased to varying degrees, underground biomass of B044, B043, B062and B065were decreased to varying degrees, root shoot ratio of B043were decreased, root length of B053, B062, B043and B066were decreased to varying degrees.2.The changes of light response curve showed same trends for the21kinds of fiber herbaceous energy plants, Net photosynthetic rate enhanced with the increasing of photosynthetic active radiation, and net photosynthetic rate increased rapidly in the weak light area, but after photosynthetic active radiation reached certain degree the net photosynthetic rate is increased slowly and the curve becomes flat. At the same photosynthetic active radiation, ck of net photosynthetic rate value is greater than the net photosynthetic rate under moderate drought stress treatment of21kinds of fiber herbaceous energy plants. Using non rectangular hyperbola model to simulate, the results show that the decision coefficient are above0.95under ck and moderate drought stress treatment instructing the fitting of specification mode is good, can very good reflect21kinds of fiber herbaceous energy plants leaf photosynthetic responsed to light intensity. The light response parameters were appeared consistent trends with the increasing of intensity of drought threats, show the maximum net photosynthetic rate and apparent quantum efficiency, dark respiration rate, light compensation point and light saturation point were reduced. 3. Under moderate drought stress21kinds of fiber herbaceous energy plants photosynthetic pigment have appeared significant change, results showed that:compared with ck,21kinds of fiber herbaceous energy plants photosynthetic pigment presented a part of the varieties increase and some varieties decreased under moderate drought stress, moderate drought stress treatment had a greatest influence on the21kinds of fiber herbaceous energy plants leaf carotenoids, followed by chlorophyll b, the least is chlorophyll a.4. Drought stress intensity and time had a influence on the21kinds of fiber herbaceous energy plants osmotic regulation substances accumulation, results showed that: compared with ck, varieties of soluble sugar, soluble protein and proline content appeared significant rise under moderate drought stress treatment.5. The impact of drought stress on21kinds of fiber herbaceous energy plants leaf Antioxidant protective enzyme is:compared with ck, the varieties of SOD and H2O2content had significant increases under moderate drought stress treatment; POD content in addition to the wuming and japan had significant increase under moderate drought stress treatment; MDA conten t except japan and B043had significant increase under moderate drought stress treatment.6. Under the continuous drought stress,21kinds of fiber herbaceous energy plants leaf relative water content present the overall downward trend, between the same varieties but different number of stress days leaf relative water content had significant difference (p<0,05). the orde for12kinds of Panicum virgatum leaf relative water content drop under20days drought stress is:blackwell> wuming> canada> cave in rock> newyork> trailblazer> kanlow> pathfinder> forestburg> japan> Alamo> ansai. the orde for9kinds of Miscanthus leaf relative water content drop under20days drought stress is:B062> B056> B065> B043> B053> B054> B066> B026> B044. As the extension of drought stress time,21kinds of fiber herbaceous energy plants leaf water potential had decreased, between the same varieties but different number of stress days leaf relative water content had significant difference(p<0.05).12kinds of Panicum virgatum and9kinds of Miscanthus leaf water potential and relative water content had the same drop order under20days drought stress, explaining the leaf water potential and relative water content presenting a certain correlation.7. The impact of drought stress on21kinds of fiber herbaceous energy plants root activity is:compared with ck,12kinds of Panicum virgatum root activity under moderate drought stress treatment reduced except kanlow, Alamo and japan;9kinds of Miscanthus root activity reduced under moderate drought stress treatment.8. Using principal component analysis and subordinate function analysis evaluated the drought resistance of21kinds of fiber herbaceous energy plants in comprehensive. According to comprehensive index value D, the drought resistance order of21kinds of fiber herbaceous energy plants is:B026> Alamo> B054> japan> B053> kanlow> B056> forestburg=B062> unknown> B044> pathfinder> canada> trailblazer> B066> B043> cave in rock> ansai> blackwell> B065> newyork.