Studies On Simulation Of Optimal Distribution Of Dry Matter And Growth Of Young Plants In Greenhouse Tomato

Tomato (Lycopersicon esculentum Mill. ) is an important vegetable crop in the world. An indeterminate type of greenhouse tomato can grow around one year.There is a severe competition for assimilates between vegetative sinks and generative sinks in a tomato plant. It is of an importance for growth of greenhouse tomato with high benefit how to improve the distribution of dry matter to the fruits at the farthest, decrease the superfluous vegetative growth and minimize the expense of assimilates for vegetative growth.High output of yield of greenhouse tomato always requires high input of energy. Raising young plants is an important tache for the production of greenhouse tomato. It is also an important aspect for growth of greenhouse tomato with high benefit how to reduce the cost of energy and predict accurately growth of young plants, as long period and low air temperature outside during the growth of young plants.With the rapid development of horticultural establishment in the global world, horticultural crop growth models are becoming increasingly important. The main problem for horticultural crop growth models is the validity and reliability of their use in practice. At present even in a long future it is becoming an emphasis for study of crop growth models how to use, validate and perfect them in practice.Laws of optimal distribution of dry matter and characteristics of growth with high benefit in greenhouse tomato were studied by the way of synchronous leaf pruning(SLP) designed by the author of this thesis, and simulation of SLP by reduction of vegetative sinks in TOMSIM. Here SLP means that the second leaf of each vegetative unit in tomato plant is periodically removed when it is only l-3cm long, and low old leaves are also periodically removed one vegetative unit each time, Therefore leaf pruning always keeps synchronization with plant development. Effects of reduction of temperature on growth for youngplants of different genotype tomato lines were also studied by plant growth analysis. Based on that, a model on growth of young plants of greenhouse tomato, TOSSIM, was developed. The hypothesis of balance compensation point of fruit dry matter, that of growth of tomato in greenhouse growing with high benefit based on optimal distribution in tomato plant and the concept of impedance of dry matter distribution and its biological meaning were put forward in this study. The hypothesis of balance compensation point of fruit dry matter means that there is a balance compensation point of fruit dry matter in tomato plant, and fruit dry weight will not decrease with leaf pruning as long as increment of dry matter allocated to the fruits resulted from the increased cumulative fraction of dry matter allocated to the fruits is no less than reduction of fruit dry matter resulted from leaf pruning. The hypothesis of growth of tomato in greenhouse growing with high benefit based on optimal distribution in tomato plant is described as following: it is theoretically hypothesized that reduction of vegetative sink strength, on one hand, will reduce LAI and crop growth rate, therefore total plant dry weight per square meter; on the other hand, will favor distribution of dry matter to generative sinks and improve the cumulative fraction of dry matter partitioning to the fruits, therefore compensate reduction of fruit dry weight resulted from reduction of total plant dry weight per square meter. Increased plant density will increase LAI, and compensate reduction of total plant dry matter resulted from leaf pruning. The result of the double effects is either that the same fruit dry weight is reached while the superfluous vegetative growth is reduced, therefore productive materials such as water and fertilizer are saved; or that fruit dry weight per square meter is increased with the same vegetative growth, therefore growing with higher benefit is reached. The concept of impedance of dry matter distribution means that f= SSveg.unit/ SSfruit(truss) is defined as impedance which resists allocation of dry matter to the indivi...