Responses Of Artemisia Wudanica Seedling Stage To Drought Stress Adabtability

Artemisia wudanica Liou et W.Wang is a unique native plant that distributed in Ongniud Banner Inner Mongolia.Artemisia wudanica seedlings were used as test materials to simulate drought stress experiment.The ability of drought resistance was discussed after analyzing the growth status,physiological and biochemical indicators,trends,endogenous hormone-related index trends,catheter molecular morphology and quantitative trends and other drought resistance indicators of the Artemisia wudanica seedlings.The results showed that the plant height,stem diameter,root length,and biomass of apple seedlings decreases with the decrease of soil water content.The plant height decreases by 3.39cm,6.25cm and 10.72cm in the CK group with 4?8?and 12 true leaf times compared with the HS group;stem diameter decreased by 0.57mm,0.41mm and 0.42mm and root length decreased by 0.55cm,1.27cm,1.15cm;total biomass decreased by 1.65g?5.56g?6.43g and the root shoot ratio increased with the decrease of water content,and increased by 4.5%?5.57%and 8.12%respectively.In 4 drought treatments,soluble sugars accumulated with prolonged stress time;the relative permeability of cell membrane and proline content showed in increasing trend.Soluble sugars in leaves and roots all reached the highest values under severe stress at 12true leaf stages;the MDA content in leaves and roots reached the highest value under moderate stress at 12 true leaf stages.The activities of SOD,POD and CAT in leaves and roots both showed an upward trend in the initial stage of treatment,and they generally increased first and then decreased in the 8 and 12 true leaf stages.The leaf and root enzyme activities reached the maximum at 12 leaf stage HS treatments:241.72?310.20U/g·Fw,162.53?226.62 U/?gFw·min?;96.02?144.69 U/?gFw·min?.Drought stress resulted in the increase of ABA and GA₃;the decrease of the ZR content and the high-low-high trend of IAA content in four,eight,and twelve true leaf stage seedlings.The contents of ABA in leaves reached the maximum values of 90.01?113.20and 126.00 ng/g·FW under HS treatment,the content of root under HS treatment group was 49.55?82.66and 99.55ng/g·FW.The contents of GA₃ in leaves reached the maximum values of 6.09?6.78and 7.88 ng/g·FW in the HS treatment.The content of GA₃of the root in HS group was 6.65?7.09and 9.31 ng/g·FW,respectively.The ZR content of leaves in the HS group was 6.98?7.33 and 8.07 ng/g·FW.While the ZR content in the root in HS group was 5.26,6.10,and 7.00 ng/g·FW respectively.The contents of IAA in the leaves in the MS group were reduced to 50.43?45.85and 41.72 ng/g·FW and the IAA content of roots in the MS group was also decreased to 40.19?35.35 and 28.73 ng/g·FW respectively.In the process of plant growth,4?8?and 12 true leaf stages:ZR/ABA in leaves and roots reached the lowest value in the HS group as the drought stress deepened.IAA/ABA ratios of root were generally higher than those of leaves.The GA₃/ABA ratio in roots of seedlings was greater than that in leaves.The GA₃/ABA ratio in leaves and roots reached the lowest value in HS group,while the ABA/Sum ratio in leaves and roots reached the maximum value in the HS treatment group.ZR/Sum showed a gradual downward trend as a whole.The ZR/Sum ratio reached the lowest value in the HS group.GA₃/Sum ratio showed a trend of increasing first and then decreasing,and the ratio of roots was greater than that of the leaf.The length of catheter seedlings showed a shortening trend with the prolongation of drought stress.From 4 pieces to 12 pieces of true leaf stage,the length of the catheter molecule length in the roots in HS group decreased about 194.558?166.3122?146.519?m.The diameter showed an upward trend,in which the diameters of the catheters in the HS group at the 4th,8th,and 12th leaf sections of the stem thicker than those in the CK group by were 72.08%?16.98%and 9.37%respectively.The tail length showed a trend of decrease-rise-decrease in the 4 and 12 true leaf stages,and it showed a trend of first decrease and then increase trend in the middle period.The thickness of the end wall of the stem catheter was decreased by 30.58%in the HS group compared with the control group in the early seedling stage.In 8 and 12 true leaf stages:HS group was increased by 19.88%and 61.49%respectively compared with the CK group and the end wall thickness of root canal molecules decreased with the decrease of soil moisture.The slope of the end wall of the catheter showed an increasing trend.During the stress period,the increase of the root in the HS group was 30.73%?27%and 26.79%respectively.The length/diameter ratio showed a declining trend,and the roots decreased most.Compared with the CK group,the HS group decreased by 34.85%?41.03%and 44.46%.