Study On Irrigation Lower Limits For Overwintering Tomato In Heliogreenhouse

Taking "NaiMoNiTa"as the material and under circumstances of covering drip irrigationwith the plastic film in the greenhouse.Taking90%of field capacity as irrigation upper limit.an experiment on the effect of which the five different percentage40%,50%,60%,70%,80%of irrigation lower limit of field capacity on tomato's growth development features,chlorophyII fluorescence parameters,gas exchange parameters,physiological indexes,yieldand irrigation water use efficieney. It provides certain theoretical basis for heliogreenhousetomato cultivation irrigation regime.the main findings are as follows:1.when the irrigation lowet limit is60%(the field capacity), the tomato plant heightand stem diameter, number of nodes, Internode length are higher than the others, plant dryweight are largest and robust growth.Irrigation lower limits of40%,50%plant height andstem diameter, number of nodes, Internode length is significantly less than other treatments,plant small, sparse leaves, subject to drought stress, but irrigation limits of40%root/shoot isthe peak.2. In the40%-80%range of irrigation limits, With soil water content lowerdown,Tomato leaf water potential always fallen down. Irrigation limits higher than60%, thewater content of plant leaves gradually increased, water saturation deficit fall slowly, strongmetabolism and plant growth is faster. When irrigation water below the lower limit of60%,tomato are subject to water stress, plant metabolism turns slowly.3. The MDA, proline, soluble sugar content of tomato leaf are irrigation lower limits of60%for the boundaries, when irrigation limits higher than60%, the MDA in leaves oftomato,proline, soluble sugar content low, health growth of tomato. When irrigation waterbelow the lower limit of60%, MDAand proline, soluble sugar content are higher, tomato aresubject to drought stress, inhibited normal metabolism.4.Under irrigation lower limits of60%,tomato leaves's photochemical quenching(qP),Tr net photosynthetic rate(Pn), transpiration rate(Tr), stomatal conductance (Gs),intercellular CO2concentration Ci are largest.indicates that when irrigation limits of60%,light energy utilization of plants are maximum, The ability of the photosynthateaccumulation are strong.5. The units of the yield of tomato under irrigation lower limits of60%is highest, up to52.96t/hm~2,respectively higher than other treatment production74.02%,45.23%,6.77%,24.60%.Irrigation limits of60%of water use efficiency is higher than the others,17.41 kg/m~3,Water use efficiency are1.09times,1.31times,1.10times and1.39times higher thanother treatment.6. Irrigation limits of field capacity of60%is suitable irrigation indexes for thecultivation of tomato in heliogreenhouse soil in Hexi region.