Salt Tolerance Evaluation And Na~+ Absorption And Distribution Characteristics Of Hybrid Rootstocks From 'Zuo Shan 1'

In this study,one-year old cuttings of 6 hybrids of V.amurensis Rupr.‘Zuoshan1'×SO4and 2 hybrids of V.amurensis Rupr.‘Zuoshan1'×101-1 were used as materials to irrigated with 100 mmol·L^-1NaCl,the salt tolerance were evaluated,and the salt tolerance mechanism were studied.The main results were as follows:1.The introduced salt-resistant rootstock 1103P was used as control,after 20 days of salt stress,rootstocks A15,A17,A34 and A35 suffered less salt damage.Salt stress reduced new shoot growth and biomass of each plant,and A15,A17,A34 and A35 showed a lower reduction.The biomass and other 12 individual indexes were converted to 3 independent comprehensive indexes,according to the cluster analysis,A34,A35,A15 and A17 had higher salt tolerance;A38,A48 and B24 had moderate salt resistant;and the salt tolerance of 1103P and B26 were sensitive,and the results were consistent with the salt damage classification.2.Compared with 1103P,the chlorophyll content,net photosynthetic rate,photosynthetic performance indexes and actual photochemical efficiency in A34 strain slightly decreased,and the coefficient deviation on excitation energy between two photosystems slightly changed.It is suggested that PSII photoinhibition occurred in different strains under salt stress.Strains with high salt tolerance could remain high pigment contents,decrease PSII excitation pressure,keep balance excitation energy,and thereby alleviated PSII photoinhibtion under salt stress in grape leaves.3.Rootstock 1103P was used as control,the contents of osmotic adjusting substances in leaves and roots of A15,A17,A34 and A35 all increased after salt stress,and the contribution of soluble sugar to osmotic adjustment reached more than 96%,and the increment of betaine and proline was more after salt stress,with an average increase of 43.72%and 50.98%respectively over the control.4.Rootstock 1103P was used as control,under salt stress,SOD,CAT and POD activity,AsA and GSH content and APX and GR activity in leaves were higher in salt-tolerance hybrids A15 and A17,ROS and MDA content were lower,and the increment of relative electrical conductivity were less,the structure of chloroplast was integrity,and the chloroplast content were higher;while the overproduction of ROS and MDA damaged the membrane integrity and reduced chloroplast content in 1103P.Salt-tolerance hybrids A15 and A17remained high antioxidase activity and AsA-GSH cycle efficiency,reduced the damage of membrane caused by lipid peroxidation,maintained the structure and function integrity of chloroplast.5.Rootstock 1103P and the paternal SO4 were used as control,the contents of ions in roots,stems and leaves of each strain were determined after 20 days of stress treatment.The results showed that the accumulation of Na⁺in the leaves of high salt-tolerant strains A15,A17,A34,A35 and B24 were less.And the leaves of strong salt-tolerant strains had high ratio of K⁺/Na⁺,Ca²⁺/Na⁺and Mg²⁺/Na⁺,maintained relatively high value of S_K,Na,S_Ca,Na and S_Mg,Na.The results showed that the root system of F₁ generation rootstock with strong salt tolerance had strong Na⁺interception,which reduced the accumulation of Na⁺in the leaves and maintained the higher content of K⁺,Ca²⁺,Mg²⁺,Fe²⁺and ion balance in plants.6.Reference to the paternal SO4:?1?The average net flux of steady-state Na⁺efflux in roots of SO4,A15 and A17 after 24 h of NaCl stress was 770,1187 and 1446 pmol·cm^-2·s^-1,respectively.The mean K⁺flux of roots after transient stress was 865,512 and 713pmol·cm^-2·s^-1,respectively,indicating that roots of A15 and A17 with stronger salt tolerance had stronger ability to expel Na⁺and to retain K⁺;?2?The expression of VvNHXP and VvHKT genes was significantly up-regulated in the roots of grape strains A15 and A17 under 100mmol·L^-1 NaCl stress,whereas the expression of VvNHXP and VvHKT genes in SO4 roots was generally lower,indicating that the NHXP gene of Na⁺/H⁺reverse transporter and the HKT gene of K⁺transporter plays an important role in salt tolerance of grapevine;?3?The Na⁺,K⁺content and total amount of root and shoot inter-seedings A15/SO4,SO4/A15,A17/SO4,SO4/A17 of rootstock-scion mutual grafted seedings after NaCl stress further confirmed the stronger transport capacity of Na⁺,K⁺.