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Northwest University of Science and Technology (2002)

Regulative Mechanism of Nitrogen Nutrition on Phyotosynthetic Efficiency of Dryland Wheat

ZhangLeiMing

Titre : Regulative Mechanism of Nitrogen Nutrition on Phyotosynthetic Efficiency of Dryland Wheat

Auteur : ZhangLeiMing

Grade : Master Thesis 2002

Université : Northwest University of Science and Technology

Résumé
Dryland agricultural production , the main limiting factor is water deficit and poor soil . On the basis of reasonable farming , dry nitrogen fertilization is an important drought stimulation of plant water status and photosynthetic efficiency can be improved to some extent , dryland fertilization stimulation conditions and drought resistance and yield mechanism is not fully understood . Clarify the regulation mechanism under drought stress conditions of nitrogen nutrition on crop growth and development process to provide a theoretical basis for improved cultivation techniques to improve farm productivity . In this experiment, field plots and long-term fertilization experiment to study the different nitrogen treatments on wheat groups of variables , leaf photosynthetic physiological characteristics and water use efficiency to achieve the following main conclusions : 1. The wheat leaf water potential and relative water content in each growth period with increasing amount of nitrogen and reduce the water retention capacity of the blade with nitrogen increased with the increase . 2 . Wheat leaf photosynthetic capacity with increasing amount of nitrogen showed the trend first and then decreased , indicating that nitrogen fertilizer can improve leaf photosynthesis efficiency , but too much fertilizer will cause a decline in photosynthetic capacity within a certain range . 3 . Under water stress Fo with leaf dehydration continues to rise , Fv / Fm are not affected , with the reduction in relative water content ΦPS II , qP and qNP of lower , indicating that the PS Ⅱ reaction center damage may be enhanced Mehler reaction to produce an active photosynthetic apparatus , such as the components of the light-collecting organs and PS II center complexes and other harmful oxygen species . 4 . Nitrogen fertilization can significantly improve wheat leaves of FV / FM , Fv / Fo , qP and qNP showed that nitrogen application on the one hand increases the solar energy share to improve the efficiency of energy conversion and PS Ⅱ potential activity for photochemical electron transfer , and the other On the one hand enhance the non-photochemical dissipation of excess light energy , help protect the photosynthetic apparatus against the destruction of environmental stress . 5. Water use efficiency and yield increased with the increase in the amount of nitrogen showed the trend first and then decreased , indicating that excess nitrogen not conducive to the efficient use of water , the increasing effect of fertilizer not only in its more important is that the water between the interaction

Mots clés : Nitrogen Nutrition Water Stress Photosynthetic physiology Chlorophyll fluorescence Water use efficiency

Présentation (Dissertation topics)

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