Water Relation And Drought Resistance For Six Provenances Of Reaumuria Soongorica Seedlings

Reaumuria soongorica seedlings of six Provenances were used as experimental materials in this study, which belong to Wuwei minqin zhazigou,Wuwei minqin xiaobakou,Zhangye shandan,Zhangye linze,Jiuquan jinta,Jiuquan suzhou provenances respectively. Water physiological index of Reaumuria soongorica seedlings for six Provenances were determinated respectively by Plant photosynthetic apparatus and Pressure chamber water potential meter,which include Water use efficiency and its related indexes, water potential and PV parameters,and so on,And they were tested and analysed by analysis of variance and correlation analysis methods.Finaly drought resistant ability of Reaumuria soongorica seedlings for six Provenances were evaluated comprehensively by using principal component analysis method and membership function method, Water Physiological Characteristics of Reaumuria soongorica seedlings for six Provenances in the homogeneous environments were invwestigated,and the difference of drought resistance of Reaumuria soongorica seedlings for six Provenances were compared, Thereby Drought excellent provenance will be selected. The results showed that:(1)The diurnal changes of net photosynthetic rate and transpiration rate of Reaumuria soongorica seedlings of six provenances showed a single peak or Shuangfeng curve, stomatai conductance showed decline curve,but water use efficiency showed a single peak or Shuangfeng or decline curve. the photosynthetic effective radiation is the main environmental factor that influences the change of net photosynthetic rate, transpiration rate and water use efficiency,and relative humidity is the main environmengtal factor that influences the change of stomatai conductance. Water use efficiency and related indicators of Reaumuria soongorica seedlings of six provenances showed no obvious dynamic trend and fluctuated with the seasons, the net photosynthetic rate,transpiration rate and stomatai conductance have reached the maximum in July,smaller in May and September,and water use efficiency have reached the lowest in July,higher in May and September.The diurnal changes of water potential showed "V" or "W" curve,and showed downward trend with the growth process,behaved a obvious seasonal dynamics.(2)The major PV parameters of Reaumuria soongorica seedlings of six provenances showed a seasonal dynamics, Osmotic potential decreased with the season, apoplastic water also generally increased, and Va /V0 and ?max increased too; It showed that the drought tolerance of Reaumuria soongorica seedlings of six provenances will be gradually increased with the growth process. water use efficiency and its associated indicators and PV parameters of Reaumuria soongorica seedlings of six provenances showed Significant differences,which showed a obvious drought difference among the six provenances.(3)Under homogeneous environmental conditions, Water Physiological Characteristics of Reaumuria soongorica seedlings of six provenances varied in a similar way during the growing season, But the individual provenances showed its different physiological regulation strategy to drought stress. Reaumuria soongorica seedlings of JQS provenance improved its water absorption capacity mainly dependent on osmotic adjustment to maintain turgor during the nutrition and flowering period,and maintained its strong drought resistance mainly rely on the conversion of the body of water form during the end of the growing season. JQJ provenance resisted drought stress mainly dependent on the ability of tolerating low water potential in the growing season. ZYS provenance have the strongest ability of maintaining maximum turgor. ZYL and WMZ provenances regulated its tissue water balance mainly rely on high elastic cell wall. The WMX provenances have relatively strong capacity of water-holding.(4)The results of comprehensive evaluation to drought resistance of Reaumuria soongorica seedlings of six provenances by principal component Analysis and membership function method were consistent, the order was JQS>JQJ>WMX>ZYL>ZYS>WMZ,showed that its parents genetic basis dominant the differences among the provenances and the capacity of drought resistance showed a increased trend with the provenance precipitation gradient. Therefore, Reaumuria soongorica seedlings of JQS and JQJ can be used as fine provenance for vegetation restoration in the area of northwest arid, semi-arid desert to afforestated.