Study On Quantification Response Of Growth And Development Of Tomato To Different Nitrogen Levels Based On The Mechanism Of Function And Architecture Interface

As one of the important vegetable cultivated crops in the world, tomao has been paying more research attentions in the field of modeling crop eco-physiological processes. At present, it is a prominent question to inject excessive nitrogen fertilizer for tomato production in greenhouse, which not only to increase cost of production but also to decrease use efficiency of nitrogen fertilizer and tomato yield, as well as a series of question to our environment. The experiments of different nitrogen concentration (N5(nitrogen concentration5mmol/L, the same below), N10, N15, N20, N25and N30) in nutrient solution were carried out in hydroponics in order to study on the mechanism of effect of applying nitrogen deficit and excess to growth and development of tomato and to clear the range of suitable nitrogen concentration for tomato production. The dissertation developed a functional-stuctural model of growth and development of tomato crop in the greenhouse based on the mechanism of feedback each other between plant eco-physiological function and morphological architecture, the stem length for simulation of which was heat quantity time of crop growth and the architectural unit of which was metamer. The model was validated in the condition of different nitrogen concentration of the nutrient solution. It might accurately quantize the relationship between growth and development of tomato and environmental condition. And it would establish theoretical basis to control growth and development of tomato by regulate and control environment and nitrogen nutrition. The contents and results of the study can be briefly summarized as follows:1A functional-stuctural model of growth and development of tomato crop was developed in the greenhouse. Empirical parameterization was performed through field measurements in ideal situations for tomato in the greenhouse.2The experiment was carried out in the condition of no nutrient stress in hydroponics in the greenhouse. The parameters of model were calibrated in the experiment. The functional-stuctural model validated in the optional condition among the treatments was verified in the experiment.3The model can not only forecast effectively the change of growth and development and structure of tomato but also simulate the change of morphological structure and biomass of tomato based on the effect of different nitrogen concentration of the nutrient solution to growth structure of tomato.(1) The rate of growth and development of tomato was0.0320(/℃/d) in the treatment of N15. It was the equivalent of the active accumulated temperature31.2501(℃d) and about2.4days per growth cycle. The functional relation of the rate of growth and development of tomato following the change of nitrogen concentration of the nutrient solution was y=-5.0032×10-5x2+0.0018x+0.0148(Relative coefficient R2=0.9851).(2) The effect of different nitrogen concentration of the nutrient solution to the maximum expansion cycle of organs was different. The functional relation of it to the maximum expansion cycle of leaf was y=0.0079x2-0.2874x+15.2920(Relative coefficient R2=0.9522); The functional relation of it to the maximum expansion cycle of fruit was y=0.0024x2-0.0855x+9.3810(Relative coefficient R2=0.9883)。(3) Applying sink strength of different organs described competitive capacity of every organ when they achieved assimilation product. It was a relative value when the sink strength of one type of organ (such as internode) was1. The allocation proportion of different nitrogen concentration of the nutrient solution to sink strength of different organs was different. The allocation proportion to stem in the treatment of N5, N10, N15, N20, N25and N30was11.11,12.20,12.82,12.74,12.66and12.20%, respectively. The allocation proportion to leaf in the treatment of N5, N10, N15, N20, N25and N30was22.22,14.63,10.26,10.83,11.39and 14.63%, respectively. The allocation proportion to fruit in the treatment of N5, N10, N15, N20, N25and N30was66.37,73.17,76.92,76.43,75.95and73.17%, respectively.(4) The effect of different nitrogen concentration of the nutrient solution to the specific leaf weight was different. The specific leaf weight of tomato was0.0055g/cm2in the treatment of N15. The functional relation of it to the specific leaf weight was y=-8.0024×10-6x2+0.0003x+0.0029(Relative coefficient R2=0.9840).(5) The effect of different nitrogen concentration of the nutrient solution to the density of fruit was different. The density of fruit of tomato was0.0178g/cm3in the treatment of N15. The functional relation of it to the density of fruit was y=-5.0003×10-5x2+0.0018x+0.0018(Relative coefficient R2=0.9959).(6) The dry matter content of fruit was0.1307in the treatment of N15in the experiment. The functional relation of it to the dry matter content of fruit of tomato was y=-0.0003x2+0.0119x+0.0213(Relative coefficient R2=0.9945).(7) The trend of simulated value and observed value of accumulating biomass of every organ in the condition of different nitrogen concentration if nutrient solution indicated a high consistency.4. The process of growth and development of tomato was simulated by the visual method.