Effects Of Nutrient Solution PH And Salt Stress On Growth And Physiological Metabolism In Ginger

Soil acidification and salt stress are important environmental factors affecting plant growth and development,in order to study the effect of growth and physiological metabolism of ginger under nutrient solutionpH and salt interaction stress,the effects of nutrient solutionpH and salt interaction stress on the growth and related physiological metabolism of ginger of‘Shannong 1'were investigated undersalt and acid stress by nutrient liquid sand culture.The main resuts are asfollows:1.Under the conditions of this experiment,the effect of salt stress onyield is greater than the effect of pH on yield.Both pH and salt stress have significant effects on quality.There is a significant interaction between pH and Na⁺concentration.when the pH value was 5.05⁶.14and the Na⁺concentration was 16.46⁴8.64 mmol·L^-1,the yield and quality reach the expected value.2.With the increase of stress time,the salt stress significantly increased O₂^-.production rate and H₂O₂ content in ginger leaves,resulting in a continuous increase in MDAcontent and electrolyte leakage rate and the activities of antioxidant enzymes?SOD,POD and CAT?in ginger leaves enhanced first and then reduced.At the same salt concentration,low pH enhanced the activities of antioxidant enzymes?SOD,POD and CAT?and increased AsA content and GSH content,significantly decreased the accumulation of reactive oxygen.3.The results showed that under salt stress treatment,total nitrogen,nitrate nitrogen,reducing sugar and sucrose content in leaves decreased,nitrate reductase?NR?,glutamine synthetase?GS?,glutamate synthase?GOGAT?,sucrose phosphate synthase?SPS?and sucrose synthase?SS?enzyme activities also decreased,and the content of ammonium nitrogen?NH4⁺-N?in leaves increased.At the same salt concentration,low pH could effectively alleviate the inhibitory effect of the salt stress on NR?GS?GOGAT?SPS and SS,significantly increased the nitrate nitrogen,total nitrogen and sucrose content,reduced ammonium nitrogen contents.In enlargement stage,under same salt concentration(Na⁺=100mmol·L^-1),compared to pH 6.0,theNO₃^--N content and sucrose in ginger leaves treated with pH 4.0 were increased by 21.74%and 34.12%,respectively,and the activities of NR and SS were increasedby45.39%,75.41%.4.With salt stress time prolonged,the photosynthetic pigments,net photosynthetic rate?Pn?,stomatal conductance?Gs?,maximum photochemical efficiency?Fv/Fm?,actual photochemical efficiency??PS??,and photochemicalquenching?qP?of ginger all continuedtodecline.While non-photochemicalquenching?NPQ?gradually increased.The stomatal limitation value?Ls?first increased and after wards decreased.However,intercellular carbondioxide concentration?Ci?first decreased and after wards increased.Suchas in tillering stage,compared to ginger plant without Na⁺concentration?pH 6.0?,thecarotenoids content were reduceaed 19.10%,31.46%in Na⁺=100 mmol·L^-11 with pH=4.0or Na⁺=100 mmol·L^-1 withpH=6.0,Pn were decreased by 32.52%?53.93%.?PS?were decreased by 19.46%,31.13%.NPQ were increased by 28.89%,38.41%.5.The results showed that the mineral elements in various organs of ginger varied in response to the time and the pH and Na⁺concentrations,and the main difference factor was Na content.Salt stress significantly enhanced contents of Na in various organs of ginger,and decreased the content of mineral elements such as K,Ca and Mg;K/Na and Ca/Na ratios in different organs of ginger decreased with the prolongation of stress time.The order of K/Na and Ca/Na ratios in different organs was leaves>rhizome>roots.In the interaction of pH and salt,low pH significantly reduced contents of Na in various organs of ginger,and increased the content of mineral elements such as K,Ca and Mg and K/Na and Ca/Na ratios.Such as stedling stage,under same salt concentration(Na⁺=100 mmol·L^-1),the Na content in roots and leaves treated with 4.0 of pH was reduced by 36.33%and 30.18%compared with 6.0 of pH,K content were enhanced by 13.74%,24.62%.