The Effect Of Low Temperature And Weak Light At Flowering Stage On Yield And Fruit Quality Of Greenhouse Tomato

Taking "Jinfen 5" as material to set different treatments of low temperature and weak light in an artificial climate chamber.The treatments included 18/8℃(maximum/minimum temperature,Tmax/Tmin)×400μmol·m-2·s-1(photosynthetically active radiation,PAR),18/8℃x200μmol·m-2 s-1,16/6℃×400pμmol·-m-2 s-1,16/6℃×200pμmol·m-2·s-1,14/4 ℃x400μmol·m-2·s-1,14/4 ℃×200μmol·m-2·s-1 12/2 ℃×400μmol·m-2·s-1,12/2 ℃x200μmol·m-2·s-1,and each treatment duration was 2d,4d,6d,8d,and 10d,respectively.The control group(CK)was set as 28/18℃×80μmol·m-2·s-1 which was optimal growth conditions for plants.Observing the flowering and fruiting trait and determined the flower pollen,yield and fruit quality,in order to provide a theoretical basis for the defense and risk assessment of low temperature and weak light disasters in tomato facilities.The results are as fellows:(1)Low temperature and weak light stress will inhibit the flowering of tomato and slow the flowering speed of tomato,but the plant can recover to CK level and even can promote flowering to a certain extent,if the stress time will not exceed 4 days.Stress time more than 6 days will delay plant flowering and reduce the number of flowers and pollen vigor.Meanwhile,there are falling flowers.Low temperature and weak light had little effect on the flowering rate of tomato,and had a significant effect on pollen vigor.The effect was greater with the increase of stress level,and the flower dropping rate was positively correlated with the degree of low temperature and low temperature.(2)The number of fruit set in tomato showed "S" change with time,and the fruit setting period of tomato plants that were treated with low temperature and weak light for more than 4 days was obviously delayed.The fruit setting time at 12/2℃×400μmol·m-2·s-1 for 10 days was the latest.It is 10.5d delayed compared to CK.Under low temperature and weak light stress,there was a positive correlation between the maformed rate of tomato and the degree of stress.The fruit setting rate,the number of normal fruit per plant,and the yield per plant showed a downward trend with the increase of the stress degree.Low temperature and weak light had no significant effect on tomato yield for 2 days,except for 12/2℃×200μmol·m-2·s-1 treatment of which yield decreased by 10.61%compared with the CK.However,tomato yield reduction after 6-day treatment at 14/4℃and 12/2℃reached above 60%,and the treatment which treated at 12/2℃×200μmol·m-2·s-1 for 10 days had the lowest yield and its yield reduction was 78.44%.(3)Vitamin C,lycopene,soluble sugar,soluble solids content,and acid-sugar ratio of fruits decreased with the decrease of light under the same treatment temperature for the same number of days;Under the same light and the same treatment days,the content of vitamin C,lycopene,soluble sugar,soluble solids,and acid-sugar ratio decreased with the decrease of treatment temperature;while under the same treatment,the variation decreased with increasing stress days;But the change rule of organic acid content was opposite.(4)The low temperature and weak light exposure continued for 2 days,which had little effect on the growth and development of tomato plants;Analysis of variance showed that the temperature had the most significant effect on the plants during the low temperature and weak light treatment.