Physiological Response To Drought Stress In Four Kinds Of JUNCAO

This experiment consisted of four main parts.Firstly,the drought resistance of four kind of JUNCAO were evaluated and analysised by PEG simulated drought stress,on the basis of the rusults,Experiments were designed to explore effects of drought stress on growth,physiological and biochemical indices in leaves of four kind of JUNCAO,Explore photosynthesis of four kind of JUNCAO response to drought stress,Explore roots of four JUNCAO response to drought stress,Thus fully Explore four kind of JUNCAO adaptation and defense mechanisms to drought stress in order to take advantage of the physiological and biochemical of JUNCAO response to drought stress to guide the water-saving irrigation work and provid a valid theoretical basis for improving JUNCAO drought resistance.While providing scientific guidance and theoretical basis for the planting of JUNCAO in desertified areas.The main contents and results of the experiment were followed:(1)The drought resistance of four kind of JUNCAO were evaluated and analysised by PEG simulated drought stress with subordinate function analysis in line with growth indexes and physiological indexes.Drought resistance of JUNCAO from strong to weak:Arundo sp.>Arundo sp.>Pennisetum giganteum z.x.lin>Pennisetum purpureum and drought resistance Arundo sp.?Arundo sp.(2)The RWC of strong drought-resistance(Arundo sp.)decreased less under drought stress,it had strong water retention capacity.The RWC of weak drought-resistance(Pennisetum purpureum)decreased greatly under drought stress,it had weak water retention capacity.water retention capacity from strong to weak:Arundo sp.?Arundo sp.>Pennisetum giganteum z.x.lin>Pennisetum purpureum.MDA content changes reflect the degree of membrane lipid oxidized.The degree of cell damage:Pennisetum purpureum>Pennisetum giganteum z.x.lin>Arundo sp.Soluble protein is osmotic adjustment.its content to some extent reflect the 4 JUNCAO osmotic adjustment ability.Under drought stress,the soluble protein content of Arundo sp.increased significantly,it effectively resist and adapt to drought stress.but soluble protein content of grass increased to a lesser extent and it began to decline under moderate drought stress,indicating that osmotic adjustment ability of xiangcao is the worst.There was no significant correlation between the Pro content of plants and drought resistance,Pro content increased under drought stress may be the result of damage to the plant,and the changes of Pro content as identified plant drought resistance index has some shortcomings,and therefore Pro should not as 4 JUNCAO osmotic adjustment,Pro is indicators of reflecting the sensitivity of plants to drought stress.(3)Under drought stress,photosynthetic parameters and chlorophyll fluorescence parameters of four kind of JUNCAO showed different degrees of change.A,E and stomatal conductance(Gs)the decrease larger with drought stress intensified.Under drought stress,Fv/Fm?Fv/Fo values of JUNCAO decreased in varying degrees of magnitude,strong drought-resistance(Arundo sp.)decreased less showed that Its lesser extent of the damage of photosystem II.(4)four kind of JUNCAO root morphology index(root length,surface area,volume)and dry matter volume showed different degrees of decline under drought stress.the stronge drought resistance of JUNCAO decrease little in its index,indicating that dtought stress had little Inhibition on root growth of JNCAO.