| Facility agriculture is an important development direction of the modern agriculture, the most critical technical of the facility agriculture development is controlling the facility environment. Temperature regulation is an important part of the facility environment control. The effects of different temperature control on the growth, yield and quality of crop was different. In recent yeas, scholars are very concerned about how to regulate the growth and quality of the facility crop by using the DIF. This feature is environmental-friendly and energy-saving. It conforming the " high quality, efficient, ecological and safe" on the direction of the facility agriculture development. Tomato is the main kind of facility vegetables in our country, and cultivation has reached680million mu uhtil2012. The facility tomato production are still facing the low yield, poor quality, and difficult to anniversary production. There are many previous studies on the effects of the high and low temperature on tomato, and the research about the different DIF on growth of tomato was few.In order to reveal effects of the DIF to the photosynthetic characters,the fluorescence parameters and protective enzyme characteristics on different growth stage to facility tomato, a research has been conducted to tomato cv.’Jinguan5’. We desighed the two-factor test of different daily average temperature and DIF. The average temperature is setting two levels of18℃and25℃. The diurnal temerature is setting0℃,6℃and12℃three levels. There are a total of six DIF treatments. The results provide scientific basis and technical support for the environmental control to facitlity tomato. The main findings are as follows:(1) The tomato leaf chlorophyll content (Chl a and Chl b) are gradually increased with the DIF increase and are significantlypositively correlated with DIF. At18℃average temperture, the content of carotenoid in tomato leaves is the highest under12℃DIF treatment and the minimum under6℃DIF treatment; The Pmax, Amax, Aq and Ce of tomato leaves reached highest under6℃DIF treatment and lowest under12℃ DIF. At25℃average temperture, coroteniods and DIF are negative correlation; The photosynthetic parametres vary at four growth periods, where young fruit and maturity stage6℃DIF was the maximum value and0℃DIF was the minimum value; The values in seeding and flowering stages also showed greater than the treatment without DIF. The DIF treatment significantly increase the photosynthetic pigment content of tomato leaves.6℃DIF has the strongest photosynthetic capacity and can effectively promote the photosynthesis and conductive to growth of tomato.(2) Tomato leaf chlorophyll fluorescence parameters such as Fv/Fm, qP, NPQ and ETR are not a linear relationship with the DIF and with the increase of DIF present different trends. When the average temperature is18℃, the maximum value of Fv/Fm and ETR and the minimum value of NPQ were in the treatment of28℃/22℃. When the average temperature is25℃, Fv/Fm under12℃DIF was the highest, qP and ETR under6℃DIF have the hghest values and NPQ was the lowest in6℃DIF treatment.(3) When the average daily temperature is18℃, the maximum value of SOD, POD and CAT enzume activity and the minimum value of MDA content of tomato leaves occurred at21℃/15℃. When the average daily temperature is25℃, the treatment of31℃/19℃had the highest SOD activity and the maximum value of POD and CAT enzume activity and the minimum value of MDA content appeared at28℃/22℃. Moreover, SOD and POD activity are always higher in25℃than in18℃daily average temperature. The content of MDA is just the opposite.Within the appropriate temperature range, appropriately increase the DIF can promote photosynthesis of tomato. When beyond the optimum temperature range, a over large DIF will cause harm to plants. |
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