Effects Of Simulated Acid Rain On Indocalamus Barbatus McClure And The Regulating Of Exogenous Nitric Oxide

To understand the effects of simulated acid rain on the Indocalamus barbatus McClure and the regulating of exogenous nitric oxide,this study with the donor of sodium nitroprusside researched the effects of exogenous nitric oxide on the bamboo cultured in pots under simulated acid rain stress condition.The results showed as follows:1.Effects of simulated acid rain on Indocalamus barbatus MeClureThe results of the diurnal changes of photosynthesis indicated that net photosynthetic rate(Pn)of the control group showed a single peak curve,and the Pn of treatment groups showed a atypical double-peak curve with the phenomenon of photosynthesis midday depression.Under the stress of simulated acid rain,the daily average and the maximum Pn decreased significantly with the stress strength increasing.Under the stress of simulated acid rain,Pn and apparent quantum yield(AQY)decreased,but light compensation point(LCP),CO₂ compensation point (CCP),dark respiratory rate(Rd)increased.The results of chlorophyll fluorescence parameters showed that PSII maximal photochemical efficiency(Fv/Fm),PSII effective photochemical efficiency(Fv'/Fm'),PSII potential activity(Fv/F₀),photocHemical quench(qP)all decreased,and non-photochemical quench(NPQ)increased rapidly and then declined gradually under the stress of simulated acid rain. Chlorophyll relative content(SPAD)and Soluble protein content(Pr)declined slowly and then increased gradually,but the content of free radical increased rapidly.At the same time,superoxide dismutase(SOD)and peroxidase(POD)varied broadly.Through observation of outside morphology and electron microscope,the result demonstrated that leaves were notably damaged at pH 2.0,leaves were damaged lighter at pH 3.0 than at pH 2.0,and leaf cells were almost normal at pH 4.0.2.The regulating of exogenous nitric oxide under simulated acid rain on Indocalamus barbatus McClureThe treatment with exogenous nitric oxide(400mg/L SNP(S2)),the Pn of Indocalamus barbatus McClure showing a double-peak curve at pH 3.0(S)Transformedinto a single peak curve.AQY and CE were improved,LCP,CCP and Rl were reduced under the exogenous nitric oxide with the suitable concentration.The results of chlorophyll fluorescence parameters showed that Fv/Fm,Fv'/Fm',ΦPSâ…¡,Fv/F₀,qP decreased slowly,the activities of SOD and POD increased,and inhibited the decrease of acid rain on SPAD and Pr under the treatment with exogenous nitric oxide(100mg/L(S1)or 400mg/L(S2)),especially the treatment with 450mg/L sodium nitroprusside was the best.Through the monitoring of visual injury,the result demonstrated that the treatment of 100mg/L(S1)and 400mg/L(S2)were damaged lighter than that of pH 3.0,but the treatment of 700mg/L(S1)and 1000mg/L(S2)appeared many necrotic spots.According to above results,it is concluded that the damage of Indocalamus barbatus become severer with the stress strength increasing,and the exogenous nitric oxide with the suitable concentration can relieve the damage of acid rain on Indocalamus barbatu.This paper is aimed to study the effect of the stress of simulated acid rain on the bamboo and provide theoretical foundation of regulation of nitric oxide on simulated acid rain stress,and offer reference for the ecological application of garden ornamental bamboo in Acid Rain Area.