Effects Of Water And Source/Sink Ratio On The Photosynthesis Physiology And Yield Of Processing Tomato

【Objective】In order to increase the yield level and exert the high yield potential of processing tomato it is great importance to study the regulating effects of the source-sink alteration by leaf removal treatment on the photosynthetic rate, dry matter accumulation and partition above ground of processing tomato.【Methods】Liger87-5 was selected as experimental materials, there were three levels of water stress treatments by controlled irrigation , controlled the lower limited of soil water content in 0—60 cm soil layer at 75%±2% (no stress, controll) ,60%±2% (mild stress),45%±2% (severe stress) of the field water capacity. Irrigation was 30 mm.The source treatments were as follows:when the leaf area index reached 2.0-2.5 removed lower leaves every 7 day , determinated to leaf area and dry weight, to removed leaves area was about all of the existing 10% to 15%.【Results】Effects of water and source/sink ratio on the Photosynthetic physiology , photosynthesis and the accumulation and distribution of production and water use efficiency of processing tomato leaves.The results were as follows:1. Effects of water and source/sink ratio on source .In various stages,with increased water stress leaves water content and relative water content reducted significantly, the relative water deficit increased significantly; Water content , relative water content and relative water deficit were not affected significantly by leaf removal and the interaction of water and leaf removal. Under water stress leaf area index , SPAD, chlorophyll and cartenoid content of processing tomato leaves decreased significantly, those were not affected significantly by leaf removal and the interaction of water and leaf removal . In various stages photosynthetic rate reducted significantly under water stress,that was affected significantly by leaf removal and the interaction of water and leaf removal .With intensified water stress, maximum fluorescence(Fm), the ratio of the variable to minimal fluorescence (Fv/Fo), the ratio of the variable to maximum fluorescence(Fv/Fm ,φPo), performance indexes(PIABS and PICS), probability that a trapped exciton moves an electron further than QA- electron(ψo),probability that an absorbed photon moves an electron further than QA- electron(φEo), area between fluorescence curve and Fm(Area), relative area between Fm and Fo(Sm), tutn over number of QA(N), electron transport flux per RC and Cs (ETo/RC,ETo/CSo) decreased,the minimal fluorescence(Fo), Relative variable fluorescence intensity at the J-step (Vj),Absorption flux per RC and CSo (ABS/RC,ABS/CSo), Trapped energy flux per RC and CSo (TRo/RC,TRo/CSo), Dissipated energy flux per CS and CSo(DIo/RC,DIo/CSo) increaded. Fo,Fm,Sm,N,Vj,ABS/RC,ABS/CSo,TRo/RC,TRo/CSo,DIo/RC and DIo/CSo of leaf removal treatment higher controll,Fo/Fv,Fv/Fm,φPo,PI(abs),PI(cso),ψo,φEo,Area,ETo/Rc and ETo/CSo of leaf removal treatmenter lower controll。Processing tomato leavers appeared light inhibition, inactivation of reaction centers and inhibition of the electron transport at the acceptor side of PSII.With increased water stress, the dry matter accmulation and the average growth rate of vegetative organ of processing tomato decreased, there of leaf removal treatment lower controll.With growth and development, the allocation rates of dry matter of vegetative organ decreased, that was affected significantly by water and leaf remova in the late growth stage.2. Effects of water and source/sink ratio on sink.The growth of vertical and horizontal diameter , the fruit dry matter accmulation and dry matter accmulation above ground of processing tomato varied in S shape manner,and decreased significantly under water stress. The growth of vertical and horizontal diameter was not affected significantly by leaf removal and the interaction of water and leaf removal . The fruit dry matter accmulation, dry matter accmulation above ground reduced and were affected significantly by leaf remova and water. Water stress and leaf removal lead to the largest dry matter accumulation above ground gradually reduce ,the time of maximum accumulation rate advance, the average rate of accumulation and the days of dry matter accumulation gradually reduce.3. Effects of water and source/sink ratio on yield and yield components of processing processing tomato.Under water stress, processing tomato average fruit weight, fruit number and yield reduced. there of leaf removal treatment lower controll. Processing tomato average fruit weight and yield were affected significantly by water ,leaf removal and the interaction of water and leaf removal.4.Effects of water and source/sink ratio on the water use efficiency and the harvest index of processing tomato.Under mild stress bioamss and yield the water use efficiency of processing tomato was lightest, bioamss and yield the water use efficiency of leaf removal treatment lower controll. water stress and leaf removal affected significantly WUE of processing tomato. The harvest index of processing tomato was affected significantly by water and the interaction of water and leaf removal, that was not affected byleaf remova.Mild stress improved the harvest index of processing tomato.【Conclusions】Leaf removal affected significantly source and sink of processing tomato under water stress. With water stress, the relative water deficit , leaf area index , chlorophyll and cartenoid content,photosynthetic rate of processing tomato reducted significantly,that lead to dry matter accmulatio and yield reduct. Water and leaf source were limiting factor of improving processing tomato yield. Regulating water and maintaining appropriate soil moisture, reducing the loss of leaves, and cultivating strong source, would improve processing tomato yield.