外源CO和H2S对NaCl胁迫下加工番茄幼苗光合及叶绿素荧光动力学的影响OA北大核心CSTPCD

[Objectives]We studied the mechanism of carbon monoxide(CO)and hydrogen sulfide(H2S)on alleviating NaCl stress to crop seedlings,to provide a theoretical basis and technology for efficient crop production in the secondary salinized soil.[Methods]A soilless cultivation experiment was carried out using a processing tomato strain KT-7 as the test material.The donor for carbon monoxide(CO)was hemin solution(15 μmol/L),and for H2S was hypotaurine solution(50 μmol/L).In addition,zinc protoporphyrin solution(25 μmol/L)was used for heme oxygenase inhibitor,and H2S scavenger hypotaurine solution(HT,100 μmol/L)was used as the requirement of the treatments.There were 6 treatments in the experiment,except for CK0(irrigating normal nutrient solution and foliar spraying clean water),the other five treatments were all irrigated with a nutrient solution containing 200 mmol/L NaCl,and foliar sprayed clean water(CK1),CO,CO+HT,H2S,and H2S+ZnPPⅨ,respectively.When the seedlings were at the stage of 4 leaves-1-sprout,NaCl stress and foliar spraying were carried out for consecutive six days then the morphological indicators were investigated,Li-6800 portable photosynthetic system was used to measure the photosynthetic parameters.The Imaging-PAM modulated fluorescence imaging system was used to determine the fluorescence parameters of chlorophyll,and the plant efficiency meter was used to measure the leaf green fluorescence kinetic curve(OJIP).[Results]After 6 days of NaCl stress,the net photosynthetic rate(Pn),actual photochemical efficiency[Y(Ⅱ)]and PSⅡperformance indicators(PIABS and PI(CSM))of the seedling leaves decreased significantly,the OJIP curve was deformed,and the K point appeared.Both CO and H2S treatments improved the photosynthetic pigment content,photosynthetic parameters,comprehensive performance of PSⅡand electron transfer efficiency on the receptor side,revised the deformation of the OJIP curve by raised the J point,I point,and P point,and falling ΔK.Compared with CK,the Pn,apparent CO2 utilization rate(CUEapp),Y(Ⅱ)and electron transfer rate(ETR)increased by 75.63%,100%,60.00%and 57.72%in CO treatment,and increased by 65.95%,100%,55.00%and 52.68%in H2S treatment.Both the CO and H2S treatments reduced the proportion of non-photochemical quenching and heat dissipation,and reduced the damage of the PSII donor side oxygen evolving complex(OEC).The CO+HT treatment was recorded similar parameters with CO treatment,while H2S+ZnPPⅨtreatment was recorded significantly lower pigment content,Pn,Fv/Fm,Y(Ⅱ),qL,ETR,PIABS and PI(CSM),but significantly higher heat dissipation ratio,compared to those in H2S treatment.[Conclusions]Both exogenous CO and H2S are conducive to optimize the PSⅡenergy distribution ratio,and protect the photosynthetic electron transport chain from salt damage.CO maybe act in the downstream of H2S involving in the photosynthesis,and intensify the effect of H2S on improving the salt tolerance of tomato seedlings.