| In recent years,lead(Pb)pollution in heavy metal pollution and sulphur dioxide(SO2)pollution in air pollution have become more and more serious.In harsh environ ment,the growth of greening plants has changed,and their landscape effects have been affected.Wild herbaceous plants,as an important part of landscape application,are oft en neglected.Glechoma longituba is a kind of herbal plant with strong adaptability and high gardening.It has broad application prospects.Therefore,Glechoma longituha was used as experimental material in this study.The stress of heavy metal lead and SO2 was simulated.The responses of Glechoma longituba to the stress of Pb and SO2 deriv atives(Na2SO3-NaHSO3)were studied from the morphological and physiological charact eristics of plants.The results are as follows:1.The damage degree of Glechoma longituba was different under different concentr ation of lead.The leaf length,leaf width and leaf area of Glechoma longituba showed obvious difference.The leaf length.leaf width and leaf area of Glechoma longituba de creased gradually with the increase of lead concentration,indicating that lead treatment inhibited the growth of Glechoma longituba.In addition,under lead stress,the soluble protein content of Glechoma longituba decreased,while the content of malondialdehyde(MDA),cell membrane permeability,free proline and soluble sugar increased gradually.The activities of SOD.POD,CAT,APX,PAL and PPO in leaves of Glechoma longit uba increased at first,and the lead treatment over 800 mg·kg-1 showed a decreasing tre nd with the prolongation of stress time,indicating that Glechoma longituba had a certai n resistance to lead pollution below 800 mg·kg-1.2.Lead stress can also affect the photosynthesis of Glechoma longituba.In this stu dy,the content of Pn,Tr,Gs and chlorophyll in leaves of Glechoma longituba increase d first and then decreased when the concentration of lead was 100 mg·kg-1,300 mg·kg-1 and 500 mg·kg-1,while other concentration treatments continued to decrease.Ci was negatively correlated with the concentration of lead stress,showing a continuous upwar d trend.In addition,the photoresponse curve showed that the Pn of Glechoma longitub a leaves increased gradually at first and then decreased slowly in a certain light intensi ty range,and the higher the concentration of lead,the more the decrease.Under lead s tress,Amax,Rd,LSP and AQE in leaves of Glechoma longituba decreased gradually,w hile LCP increased gradually.In onclusion,lead stress can affect the normal photosynt hesis of Glechoma longituba.3.Stress data of SO2 derivatives(Na2SO3-NaHSO3)showed that with the prolongati on of time and the increase of SO2 derivatives treatment concentration,the more obvio us the injury symptoms of Glechoma longituba were,and the leaf length,leaf width an d leaf area of Glechoma longituba decreased gradually.There was no significant differe nce between the treatment of 20 mmol·L-1 and the control at the initial stage of stress(P>0.05),but there was significant difference between the other treatments and the co ntrol(P<0.05).At the same time,chlorophyll content and soluble protein content in lea ves of Glechoma longituba gradually decreased with stress time,while other indicators such as malondialdehyde content(MDA),cell membrane permeability,free proline conte nt and soluble sugar content gradually increased and tended to stabilize,especially the t reatment concentration of 150 mmol·L-1 and 200 mmol·L-1 was the most different from the control.In addition.SOD.POD,CAT and APX activities of Glechoma longituba 1 eaves increased rapidly at first,but with the prolongation of treatment time of SO2 deri vatives,the concentrations of 150 mmol·L-1 and 200 mmol·L-1 began to decrease.The data showed that there was no significant difference between the treatment of 20 mmo 1·L-1 and the control at the early stage of stress(P>0.05).In addition,the activities of PAL and PPO increased first and then decreased when Glechoma longituba was stresse d by SO2 derivatives. |
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