Effects Of High Temperature And Humidity On The Development Of Young Fruit Of Facility Tomato

High temperature and high humidity are one of the main meteorological disasters of facility tomatoes.So far,the mechanism of the influence of different humidity on the development of facility tomato young fruits under high temperature stress is still unclear.For this reason,an experimental system was designed to study facility tomato photosynthesis,transpiration,pollen vitality,fruit Changes in horizontal and vertical diameter,fruit index,and endogenous hormones.The experiment uses tomato variety"Jin Fen5"as the research material.A three-factor experiment of air temperature,air relative humidity,and duration is designed,with the highest daily temperature/the lowest daily The temperature(?)is set to 4 levels:32?/22?,35?/25?,38?/28?,41?/31?,and the relative air humidity setting is:30?40%,50%?60%,70%?80%,the duration is set to:4,8,12 days,the test treatment is carried out in the flowering period and young fruit period of the tomato,and the maximum daily temperature is 25?,Tomato seedlings with an air humidity of 50%as a control(CK).The main findings are as follows:(1)For the same PAR,the net photosynthetic rate Pn continuously decreases with the increase of temperature,and presents a slow increase trend with the continuous increase of humidity.The light response model has different adaptability to different high temperature and high humidity treatments.The simulation effect of different light response parameters varies with different models.In general,the right-angle hyperbolic modified model has the best fitting effect,followed by the non-right-angle hyperbolic model.,Exponential model and right-angle hyperbolic model.With the increase of temperature,the overall?,Pnmax,LSP,LCP,and Rd gradually decrease;with the increase of humidity and the extension of the treatment time,the overall?,Pnmax and Rd gradually increase,and the treatments at32?,38?and 41?The LSP first decreased and then increased,gradually decreased at35°C,and the LCP performance was different.(2)With the deepening of the high temperature stress,G_s,T_r,the dry fresh weight and dry fresh weight R/S of the underground parts all increased first and then decreased.?w,Rv and the fresh weight of the above-ground parts gradually decreased.Dry weight changes are not significant;under high temperature conditions,with the increase of air humidity and treatment time,?w,G_s and T_r continue to increase,R/S and Rv gradually decrease,and dry and fresh weight changes are not significant.(3)With the increase of high temperature stress,the flowering rate of plants gradually decreases,but the falling rate of flowers is opposite.With the increase of humidity and treatment time,the flowering rate of 32?-38?treatment increased first and then decreased,and the rate of flower drop gradually increased.The flowering rate of 41?treatment gradually decreased,and the rate of flower drop first increased and then decreased.The effect of high temperature stress on pollen vigor of greenhouse tomato showed obvious inhibition.With the deepening of high temperature stress,pollen vigor,pollen tube germination rate and elongation showed a decreasing trend.The high temperature of 41?almost inactivated tomato pollen.Under high temperature conditions,high humidity of70%-80%can enhance pollen vigor,increase pollen tube germination rate and elongation.(4)The transverse and longitudinal meridians of the fruit grow in an S-shape,and with the deepening of the high temperature stress,the transverse and longitudinal diameters of the fruit gradually decrease,showing 41?<38?<35?<32?<CK.When the temperature is higher than 35?,the fruit The diameter reduction rate becomes larger;under high temperature conditions,humidity treatment is shown as RH50%8d<RH30%4d<RH80%12d<CK;fruit shape index varies with temperature,humidity and treatment time Not significant,but it keeps decreasing as the time after fruit setting increases.High temperature stress has a significant effect on the endogenous hormone-related indexes of young fruit of greenhouse tomato.As the degree of high temperature stress deepens,IAA and ZT gradually decrease,ABA gradually increases,and GA₃ first increases and then decreases.Under high temperature conditions,with the increase of air humidity and the extension of processing time,IAA,ZT and GA₃ gradually decrease,and ABA gradually increases.GA₃ is the highest at 35?;ABA is the highest at 41?;ZT and IAA are the highest at CK.During the growth and development of young fruits,the levels of endogenous IAA,ZT,GA₃,and ABA will gradually accumulate and increase.