| Tomato is thermophilic plant, is one of the main vegetables in winter and spring planting, Growth process is sensitive to temperature, in winter and early spring production, the low limit of tomatoes, high-yield cultivation of a key factor. So the temperature index of tomato by low temperature stress and it is particularly important to find out the suitable climate space. This projects from national natural science fund project "the tomato leaf meteorological index of low temperature stress climate space alignment research". Due to the traditional theory of agricultural meteorology three basis points temperature is the temperature and plant temperature equal to, and does not consider factors, radiation, wind is not scientific. This paper uses German Walz company produces the modulation fluorescence spectrometer Mini-PAM 、 CID Company production of hot accidentally thermometer and Rio pury touch data recorder, and use the Logistic Simulation analysis method to analyze the data,determine the low leaf temperature indicators, Under the coercion, draw the radiation temperature, wind and temperature under the composite index of tomato column line, find out the tomato suitable climate space limit of survival Under the coercion, draw the radiation, wind and temperature under the composite index of tomato column line, find out the tomato suitable climate space limit of survival.(1) Outdoor observation found that leaf is not equal to the temperature, the temperature as a plant’s temperature is not accurate.Under the influence of the wind and radiation, moderate temperature complex relationship.Within a day, leaf sometimes is higher than the temperature, or lower than the temperature.00-06 leaf temperature is lower than the temperature; 12 night when the temperature is higher than or equal to) the temperature; 18 when night temperature is higher than the temperature.(2) In different temperature, different processing long under the influence of low temperature environment,1-4℃ temperature processing 7 d, tomato actual quantum yield Y (Ⅱ) the change of value, present the reverse "L" shape curve, and decreased with increasing time, early drops rapidly and then slow down.Maximum quantum yield Fv/Fm,1℃ under processing, Fv/Fm decrease rapidly, maximum quantum yield stress of 4 d Fv/Fm will drop to 50%.2-4℃ under processing, Fv/Fm decline slowly, but after cryogenic treatment 6 d maximum quantum yield Fv/Fm dropped to 50%. Which showed a trend of decrease, and the faster the lower the temperature drop.(3) Y (Ⅱ) actual quantum yield and maximum quantum yield Fv/Fm are characterized by declining trend, using Logistic growth curve simulation, are "S" type curve.Early reduce slow, and then is accelerated, the rule of treatment for a period of time and slow.(4) The NPQ in 1℃ under the low temperature stress and temperature processing tomato NPQ values are less than the other, almost 0 to 7 d treatment, suggesting that tomato leaf under low temperature stress suffered serious injuries, lost the ability of self-protection, plant death.Also illustrates the coordination mechanism of tomatoes for low temperature is not strong.2-3℃ temperature treatment, the treatment early is increased and then gradually reduce, then to the 7 d tend to zero, and 4-5℃ temperature treatment, early treatment is first fall and then rise, to achieve a certain amount of time and then decline.(5) Under the condition of no wind, combined with the temperature and radiation balance data, draw a line 4 degrees column under the leaf, the line is the lower limit of tomato climate space and on the column line is suitable climate space, following the death, namely with the increase of absorbed radiation, the temperature needed to reduce.The Gates with the climate of space diagram to lower limit column line rule.(6) Tomato is suitable for the survival of the determination of composite index:the different temperature, radiation balance area and indoor tomato tomatoes by stress under the chlorophyll fluorescence quantum yield Y (Ⅱ) simulation of actual t-50, the result of analysis:when the radiation balance value in this range of 0-200 W/m2,1℃ temperature circumstances, a very short time, the tomato plants will die;2℃ temperature, radiation balance value from 0-100 W/m2, less than 1 d, low temperature damage on tomato;3 ℃,4℃ cases, radiation balance value is 0 W/m2, the need for such a low temperature in 3 d,6 d above will lead to the tomato plants suffer death.In the temperature of 5℃, radiation balance within 0-1000 w/m2, more than 9 d duration, tomatoes may be compromised. |
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