Effect Of NaHCO₃ Stress On Plant Growth And Organic Acid Secretion Of 'Zuoshan1' Hybrid Rootstock Strains

In this experiment,rootstocks A11,A14,A15,A17,A34,A35,A48?V.amurensis cv.Zuoshan1×SO4?,rootstocks B24,B26?V.amurensis cv.Zuoshan1×101-1?and two control rootstocks‘1103P'?V.berlandieri×V.rupestris?and‘Crimson'?Vitis vinifera L.cv.Crimson?were used as materials.The purpose of this experiment is to evaluate the ability of NaHCO₃ tolerance,select strains with strong alkali tolerance ability,and explore the mechanism of alkali resistance.The main research results were as follows:?1?The NaHCO₃ tolerance of the potted tissue culture seedlings and the one-year old cuttings of grape hybrid rootstocks were identified.The potted tissue culture seedlings A11,A14,A15,A17,B24 and B26 were watered with100 mmol·L^-1 NaHCO₃?pH8.62?for 8days.The principal components analysis showed that A14,A15,and B24 had stronger alkali-tolerance,lower decrease water content in plants,higher root activity and lower relative leaf electrical conductivity and malondialdehyde content.The content of soluble sugar and free proline in the leaves of A15 increased highest,and the alkali resistance of‘Crimson',A11 and A17 was moderate,and the alkali resistance of‘1103P'and B26 was weak.The one-year old cuttings of A15,A17,A34,A35,A48,B26 were treated by 75mmol·L^-1 Na HCO₃?pH8.35?for 25 days.The alkali resistance of A15,A17,and A48 was stronger,and their chlorophyll content,plant water content and leaf water content were higher,and the leaves was less damaged.?2?The potted tissue culture A11,A14,A15,A17,B24,B26 were irrigated with 100mmol·L^-11 Na HCO₃,The reduction of the maximum photochemical efficiency?F_v/F_m?,photochemical quenching coefficient?q_P?,maximum photochemical efficiency?F_v'/F_m'?,maximum P700 fluorescence yield?P_m?and non regulatory energy dissipation[Y?NO?]of‘Crimson',A15 and A14 were less decreased after 8 days treatment,and the increase in regulatory energy dissipation[Y?NPQ?]is less.On the other hand,the fluorescence parameters of A11 and A17 were similar to those of‘1103P',and the amplitudes of the decrease of F_v/F_m?q_P?F_v'/F_m'?P_m and the increase of Y?NO?were larger.A14 and A15maintained at a higher level in ETR???-ETR???under NaHCO₃ stress,which relieved the inhibition of photosystem activity.?A+Z?/?A+Z+V?of A15?A17 and‘1103P'were increased by 46.3%?37.0%and 28.0%respectively under NaHCO₃ treatment,the cyanide-resistant respiration rate of A15?A17 and‘1103P'were increased by 141.5%,95.8%and 63.0%respectively compared with the control.A15 and A17 relied on the reduction of photoinhibition caused by the increase of heat dissipation of xanthophyll cycle and the cyanide-resistant respiration rate to improve their alkali resistance.?3?After 100 mmol·L^-1 NaHCO₃ treatment for 2 days,the roots of A15,A17 and‘1103P'tissue culture secreted organic acid.The main organic acids were oxalic acid,and the amount of oxalic acid secreted by A15 and A17 which had strong alkali resistance,was higher and 5.45 and 3.75 times of‘1103P'respectively.Na₃VO₄?H⁺-ATP inhibitors?significantly reduced the amount of oxalic acid secreted by each strain.The content of organic acids in roots decreased after Na HCO₃ stress in each strain,but the relative expression of VvICL in A15 after 6h treatment was 10.34 times than that of the control.The relative expression of A17's Vv PEP was 6.98 times than that of the control after 12h treatment,indicating that alkaline salt stress promoted root synthesis and efflux of organic acids.?4?The root system configurations of tissue cultures A15,A17 and‘1103P'were scanned after 2 days 50 mmol·L^-11 Na HCO₃?pH8.15?treatment.It was found that the reduction of total root length,surface area,volume and average diameter of A15 were the least.NMT showed that the internal flow rate of the Na⁺and the efflux of the K⁺in A15 and A17 hybrids was significantly lower than that in‘1103P'.The increment of Na⁺content in the roots and leaves of A15 were the least,and K⁺decreased less than that of the control after NaHCO₃ treatment.The relative expression of the VvHKT in A15 and A17 was higher after NaHCO₃ treatment,while relatively low in‘1103P'.The relative expression of VvNHXP in A15 increased and peaked at 3.81 times of the control,followed by A17,which was 3.26 times of the control,and the relative expression of Vv NHXP in‘1103P'was not expressed.After the one-year old cuttings were treated with 75 mmol·L^-1 Na HCO₃?p H8.15?for25 days,the K⁺,Ca²⁺,Mg²⁺,and Fe²⁺content in the leaves of A15 and A17 were less decreased,and the root/upground ratio of A15 and A17 also decreased less.On the other hand,‘1103P'was severely yellowed and accumulated more Na⁺in the leaves.