Effects Of Long-term Different Fertilization On Photosynthesis And Photosystem Function In Maize Leaves

Improving corn production is the main way to solve the problem of food security in China. The long-term fertilizer experiment of corn directional cultivated the markedly different soil quality and production function of characteristics in the farmland ecosystem. Therefore it provides an optimal test platform, for the study of soil nutrients, corn production capacity, fertilizer effect mechanism and selection of scientific fertilization mode under long-term different fertilization pattern. Measurement equipment for photosynthetic rate and photosynthetic efficiency, and data analysis techniques for the light response curve, rapid chlorophyll fluorescence induction kinetics curve and PS I absorption curve of820nm light, provided technical basis of proving crop photosynthetic performance.With long-term trial corn as the platform, this study using methods such as photosynthetic performance measurement, analysis technology and enzyme activity measurement technology, researched the effect of the long-term application of organic fertilizer, nitrogen fertilizer, phosphate fertilizer, potash fertilizer, on the gas exchange parameters, light response curve, the chlorophyll fluorescence induction kinetics curve, anti-ageing enzyme activity in corn ear leaves. And made a comprehensive analysis of soil fertility and fertilizer rates, maize yield, growth indexes, and leaf nutrient content, to explore the mechanism of photosynthesis and aging for changing crop yield under long-term fertilization. The conclusions is following:(1) Long-term application of organic fertilizer could significantly improve the soil nutrient status, improve plant growth status and leaf nutritional status of maize, and the effect of production is the most significant. It could increase the chlorophyll content and photosynthetic performance, improve the highlight utilization in maize leaf, reduce physiological activity in late grouting, improve the biggest REDOX ability in PS I reaction center, improve the activity of CAT.(2) Long-term application of nitrogen fertilizer could cause soil acidification, increase soil organic matter, nitrogen, phosphorus, potassium content, improve maize growth and leaf nutrition significantly, improve the corn output, increase the chlorophyll content and photosynthetic performance, improve their ability to the use of highlight, and improve the leaf physiological activity, improve the performance of the electron transport chain in PS II, improve the activity of SOD and POD. The effect of Nitrogen fertilizer on photosynthetic characteristics and yield was more obvious than p and k fertilizers, it was mainly because of nitrogenous fertilizer can increase chlorophyll content and the utilization efficiency of highlight. But excessive nitrogen could cause serious injure of photosynthetic function, cause strong inhibition in late grouting, reduce the production.(3) Long-term use of phosphate fertilizer could improve the soil total phosphorus and available phosphorus content significantly, increase the chlorophyll content, improve the photosynthetic performance obviously in late grouting, reduce the photoinhibition in late grouting, increase the use of weak light, improve Shade-endurance of corn to negative, keep the ear leaf higher physiological activity, extend the effective photosynthetic duration, improve the performance of the electron transport chain in PS II, improve the REDOX ability of PS I reaction center, improve the activity of POD, CAT. The main reason for the increase production of phosphate was that it could strengthen the utilization efficiency of weak light, reduce strong light inhibition, extend the effective photosynthetic duration.(4) Long-term use of K fertilizer could increase soil total potassium, available potassium content significantly, improve the Pn, reduce the Gs, Ci, Tr, improve the stomata adjustment ability, improve the utilization efficiency of highlight, due to physiological activity decreased in late grouting, appear serious photoinhibition, improve the performance of the electron transfer chain in PS II and the electron transfer ability on the receptor side, decline the activity of SOD, CAT, lead to crops premature aging (precocity). Under the condition of high amount of organic fertilizer, the effect of K fertilizer on promoting photosynthetic was not significant, even K fertilizer could inhibit part of photosynthetic performance.(5) The comparative study on seven kinds of model contrast research showed that the right Angle hyperbolic correction model and quadratic regression model could fit corn light response curve preferably in the light saturation, light unsaturation and light inhibition. The fitting photosynthetic parameters were more, and the photosynthetic parameters of fitting were close to the measured values. And using the average of the two kinds of models as the final solution of photosynthesis parameter values.(6) With the soil nutrient content increasing, the maize growth and yield improved, total phosphorus, total potassium content increased. The corn leaf total nitrogen content is closely associated with PSⅡ function, and the relationship between total phosphorus, potassium and PS I function close. The relationship among the corn leaf chlorophyll content and optical response parameters, photosystem function and decay resistance, but has no obvious relation with photosynthetic gas exchange parameters. There was no significant correlation between the photosystem function, anti-aging performance and apparent photosynthesis. The electron transfer performance in PS II was close to leaf POD activity, and the improving of SOD activity could inhibit the action of the PS I activity.