The Influence Of Wind-drift Sand On Physiological And Biochemical Characteristics Of Haloxylon Ammodendron Seedling

Haloxylon ammodendron is well adaptive to environment.The desert vegetitation communities dominated by Haloxylon ammodendron account for 1/10 of our country's total desert area.It is an important part of our wind breaking system.Research have shown that the harsh natural environment in desert areas led to the survival rate of Haloxylon ammodendron seedlings is very low,most of the population was declining trend.The effect of sandstorm on the regeneration of Haloxylon ammodendron population was studied,and the resistance of Haloxylon ammodendron seedlings to sandstorm was studied.The effects of sandstorm on the regeneration of Haloxylon ammodendron were studied.In this study,Haloxylon ammodendron potted seedlings as experimental materials,stress intensity in a sand to simulate different wind tunnel(5 m·s^-1,11 m·s^-1and 17 m·s^-1,winds 20 min)and the different stresses(14 m·s^-1,5 min,10 min and 20 min).Based on the study of plant physiological ecology,the photosynthesis,chlorophyll fluorescence parameters,antioxidant enzyme activity,malondialdehyde content and osmotic adjustment material content of the law,which is expected from the physiological level to reveal the impact of sand flow on Haloxylon ammodendron seedlings.Results are as follows:?1?The effect of sandstorm stress on the chlorophyll fluorescence parameters of Haloxylon ammodendron seedlings was affected.With the increase of wind and sand stress,PS?maximum quantum yield of Haloxylon ammodendron?Fv/Fm?there was a general downward trend.The Fv/Fm of Haloxylon ammodendron was not significantly different from that of the control under 8 m·s^-1wind and sand flow stress.When the wind speed increased to 14 m·s^-1and 17 m·s^-1,The Fv/Fm was significantly lower than the control?p<0.05?.The actual photon quantum yield??37?PS??of shuttle muscle PS?showed a decreasing trend.The photochemical quenching coefficient?qP?increases with the increase of wind and sand flow intensity,and the population increases first and then decreases,but the population is higher than the control.The non-photochemical quenching coefficient?NPQ?tends to increase first and then decrease.The maximum photon yield?Fv/Fm?of PS?in Haloxylon ammodendron was observed at 14 m·s^-1,the practical quantum yield of Haloxylon ammodendron?PS II?and coefficient of non-photochemical quenching?NPQ?there was a general downward trend;The photochemical quenching coefficient?qP?tends to decrease first and then decrease after low light intensity?400lux?,while the population tends to decrease at high light intensity?1500lux?.?2?The effects of sandstorm stress on the photosynthesis of Haloxylon ammodendron seedlings had some influence.With the increase of wind and sand stress,the stomatal conductance?Gs?,intercellular CO₂concentration?Ci?and transpiration rate?Tr?of Haloxylon ammodendron were gradually increased,and the net photosynthetic rate?Pn?increased first and then decreased Trend,Water use efficiency?WUE?showed a decreasing trend.Under the condition of 14 m·s^-1,The stomatal conductance?Gs?,net photosynthetic rate?Pn?,Transpiration rate?Tr?and water use efficiency?WUE?of Haloxylon ammodendron were gradually decreased with the prolongation of the attack time.Intercellular CO₂concentration?Ci?showed an increasing trend.?3?The effect of sandstorm stress on the antioxidant enzyme system of Haloxylon ammodendron seedling has some influence.With the increase of wind and sand stress,SOD activity,CAT activity and APX activity of Haloxylon ammodendron generally declines to show an upward trend,POD activity overall downward trend.The 14 m·s^-11 wind-blown sand under stress conditions,with the hit time extension,Haloxylon ammodendron assimilated SOD and POD activity and APX activity shows an upward trend in general,CAT activity showed decreasing trends.?4?The effect of wind and sand flow on the cytoplasmic membrane permeability of Haloxylon ammodendron seedling has a certain influence.With the increase of wind and sand stress,the content of malondialdehyde?MDA?in Haloxylon ammodendron was decreased first and then increased.The content of malondialdehyde?MDA?of Haloxylon ammodendron seedlings decreased under the condition of 5 m·s^-1,while the content of malondialdehyde?MDA?increased at 11 m·s^-11 and 17 m·s^-1.The content of malondialdehyde?MDA?in Haloxylon ammodendron was increased with the prolongation of the attack time under the condition of 14 m·s^-11 wind and sand flow stress.?5?The effect of sandstorm stress on the osmotic adjustment of Haloxylon ammodendron seedling has a certain influence.The content of soluble sugar?SS?and the content of soluble protein?SP?decreased with the increase of the intensity of sandstorm stress,and the content of proline?Pro?in Haloxylon ammodendron was increased first and then decreased trend.The 14 m·s^-11 wind-blown sand under stress conditions,with the hit time extension,the content of proline?Pro?content and soluble protein?SP?content of Haloxylon ammodendron were increased,and the content of soluble sugar?SS?decreased after the overall trend of decline.