Response Of Wind-sand Flow On Physiological Characteristics Of Lycium Ruthenicum Murr From Different Provenances

Wind and wind-sand flow currents occur frequently in arid and semi-arid desert areas with strong destructiveness.Strong wind-sand flow can even lead to the damage of plant young epidermal cells,membrane permeability increases,cell fluid outflow and death,and the distribution,growth and reproduction and species diversity of plants in areas with strong wind-sand flow activities are inhibited,leading to increased land desertification.Lycium ruthenicum Murr.is an ecological tree species with strong adaptability,salt and alkali resistance,drought resistance,high temperature resistance,wide ecological range,wind resistance and sand fixation in arid desert areas.They often grow in saline-alkali land,sandy wasteland or both sides of the canal.The effects of multiple stress factors such as saline-alkali,drought and wind-sand flow are the key factors restricting their growth and development.In this study,two-year-old potted seedlings of Lycium ruthenicum from Minqin and Yongjing provenances were used as experimental materials.The wind tunnel simulation experiment was carried out to determine the changes of membrane permeability,malondialdehyde（MDA）content,protective enzyme activity,osmotic adjustment substance content and chlorophyll fluorescence parameters,relative water content（RWC）,water saturation deficit（WSD）,free water content（FW）and bound water content（BW）in the leaves of Lycium ruthenicum under wind-sand stress with different durations(12 m·s^-1,blowing for 0,10,20 and 30 min)and different intensities(0,6,9,12 and 15 m·s^-1,blowing for 20 min).The physiological response differences and adaptability of two provenances of Lycium ruthenicum under wind-sand stress were analyzed to reveal the adaptability of Lycium ruthenicum.The results are as follows:1.Under the treatment of 12 m·s^-1wind-sand flow,the two provenances of Lycium ruthenicum did not cause obvious membrane lipid peroxidation with the extension of stress time,and the membrane permeability increased.With the increase of wind-sand flow stress intensity,the membrane permeability of Minqin and Yongjing increased.The MDA content of Minqin increased first and then decreased,while that of Yongjing decreased first and then increased.2.With the prolongation of wind-sand flow stress duration and the increase of stress intensity,the FW of the two provenances of Lycium ruthenicum showed a decrease trend,and BW and BW/FW showed an upward trend.The RWC was significantly lower than CK,WSD was significantly higher than CK.3.Under 12 m·s^-1 wind-sand flow stress,the peroxidase（POD）and catalase（CAT）ofMinqin provenance increased significantly under 10 min blowing,the protective enzyme system was activated under 20 and 30 min blowing,and the superoxide dismutase（SOD）,POD and CAT increased.Only POD of Yongjing provenance was significantly increased under 10 min blow,SOD cooperated with POD under 20 min blow,and SOD and CAT were significantly increased under 30 min blow.With the increase of wind-sand flow stress intensity,only SOD significantly increased in Minqin provenance under 6m·s^-1 stress,and SOD,POD and CAT significantly increased under 9 m·s^-1～15 m·s^-1.The protective enzyme system of Yongjing provenance was not activated under 6 m·s^-1 stress.SOD and CAT were slightly higher than CK under 12 m·s^-1 and 15 m·s^-1 stress,respectively,POD activity increased significantly under 9 m·s^-1～15 m·s^-1 stress.4.With the prolongation of wind-sand flow stress time and the increase of intensity,proline（Pro）of Minqin provenance showed an increase trend,and soluble sugar（SS）increased significantly.The SS of Yongjing provenance reached the peak after 20 min of12 m·s^-1wind-sand flow stress;Pro was only slightly higher than CK at 15 m·s^-1,SS and soluble protein（SP）increased significantly at 6～15 m·s^-1.5.12 m·s^-1 wind-sand flow blown for 20 and 30 min,the maximum photochemical efficiency（Fv/Fm）,the operating efficiency（Fq’/Fm’）and the maximum efficiency（Fv’/Fm’）of PSII of Minqin and Yongjing decreased significantly,and the non-photochemical quenching coefficient（NPQ）showed a downward trend.The photochemical quenching coefficient（q P）of Minqin decreased only under 20 min stress,and that of Yongjing decreased only under 10 min stress.With the increase of wind-sand flow stress intensity,Fv/Fm,Fq’/Fm’and Fv’/Fm’of Minqin decreased significantly under12 and 15 m·s^-1 stress,and q P showed an overall upward trend.NPQ was slightly higher than CK under 6 and 9 m·s^-1.Fq’/Fm’and Fv’/Fm’of Yongjing significantly decreased under 9,12and15 m·s^-1 stress,q P increased under 6 and 12 m·s^-1stress,and NPQ fluctuation decreased.6.Analysis of 17 physiological indexes of Lycium ruthenicum Murr.in Minqin and Yongjing by principal component analysis,the provenance of the Minqin is mainly by POD activity,RWC,WSD,FW,BW and BW/FW changes to response to wind-sand flow stress,and Yongjing provenance mainly responded to wind-sand flow stress through membrane permeability,FW,BW,BW/FW and Fv’/Fm’Changes.According to the membership function method,the ability of Lycium ruthenicum to resist wind-sand was ranked as Minqin provenance>Yongjing provenance.