Light response characteristics of maize seedling under different amount of compound fertilizer in the purple soil at dry-hot valley
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DOI:10.7606/j.issn.1000-7601.2018.01.02
Key Words: maize  photosynthetic parameter  fertilization  rectangular hyperbola model  non-rectangular hyperbola model  modified model of rectangular hyperbola
Author NameAffiliation
ZHAO Li School of Environmental and Resources Engineering, Southwest University of Science and Technology, Mianyang, Sichuan 621010, China 
HE Yu-xiao Institute of Resources and Environment, He'nan Polytechnic University, Jiaozuo, He'nan 454000, China 
WEI Ya-li College of Resources, Sichuan Agricultural University, Chengdu, Sichuan 6250144, China 
LIU Gang-cai Key Laboratory of Mountain Surface Processes and Ecological Regulation, Chinese Academy of Sciences, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences and Ministry of Water Conservancy, Chengdu, Sichuan, 610041, China 
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Abstract:
      In this study, three different light response models were used to simulate the effect of different compound fertilizers on the light response characteristics of maize at seedling stage. The optimal model was selected though comparing the advantages and disadvantages of different fitting models. This study could provide a scientific basis for the the research of nitrogen, phosphorus and potassium physiology and scientific fertilization of spring maize in the purple soil area by using the optimal model to simulatie the maize photosynthetic parameters. On the basis of plot fertilization test, the photosynthesis of a maize (cultivar, Changcheng799) leaves at the seedling stage was measured by LI-6400 portable photosynthesis system. The photosynthetic response characteristics of maize seedling leaves under different levels of compound fertilizition treatments were studied, and three different light response models, including rectangular hyperbola model, non-rectangular hyperbola model and modified model of rectangular hyperbola were used to selected the optimal model by comparing the fitting degree(R2), apparent quantum efficiency(α), maximum net photosynthetic rate (Pnmax), light saturation point (LSP), light compensation point (Ic) and dark respiration rate(Rd). (1) The three kinds of the models can be well applied to fitting the maize leaf Pn light response of different compound fertilizer treatments, and the determination coefficient of the three different models were all greater than 0.98. The determination coefficients in order are: the rectangular hyperbola modified model>the non-rectangular hyperbola model>the rectangular hyperbola model. (2) The four parameters of maximum net photosynthetic rate (Pnmax), light saturation point (LSP), light compensation point (Ic) and dark respiration rate(Rd) are close to the measured values by the right angle hyperbolic model. (3) The net photosynthetic rate, intercellular CO2 concentration, stomatal conductance and transpiration rate of maize on seedlings stage increased with the increasing of fertilizer application rate, but decreased by the extreme rate of fertilizer. Reasonable increase of the amount of fertilizer could increase the chlorophyll content of the maize leaves at seedling stage, and prolong the period of higher photosynthetic capacity. The results from the three models simulation show that the modified rectangular hyperbola model can best fit the light response of photosynthesis and accurately calculate main photosynthetic parameters, such as the maximum net photosynthetic rate and saturation light intensity. Thus, the modified rectangular hyperbola model can be applied to fit the light response curves of photosynthesis of maize under different compound fertilizers in dry-hot valley purple soil of Yuanmou. Therefore, the fertilization amounts ranged from 1.12 t·hm-2(N, 0.190; P2O5, 0.190; K2O, 0.190 t·hm-2) and 1.49 t·hm-2(N, 0.253; P2O5, 0.253; K2O, 0.253 t·hm-2)were the tolerable fertilization amounts.