【作者】 张丽；

【导师】 张兴昌；

【作者基本信息】 西北农林科技大学 ， 土壤学， 2003， 硕士

【摘要】 水分、氮素、光照与植物生长关系非常密切，研究水分、氮素、光照在植物生长过程中的互作效应机理，为生产上合理的水肥运筹提供理论依据和指导。本文以玉米为研究对象，采用室内试验与室外试验、盆栽试验与大田试验相结合的研究方法，主要研究不同光照、施氮、灌水水平及不同形态氮素等因素对玉米体内氮素代谢及生物产量的影响，揭示了水分、氮素、光照对玉米叶片及根系硝酸还原酶活性、叶片硝态氮含量、植株全氮含量，光合作用以及根系和地上部生物产量等的互作效应。主要研究结果为： (1)供施铵态氮肥的玉米叶片硝酸还原酶活性在低光低氮时最高，而供施其它三种氮肥的叶片硝酸还原酶在高光高氮下活性最大，而四种氮肥处理的玉米根系硝酸还原酶在高光低氮下活性最大。适当增加硝态氮施用量可提高玉米叶片和根系硝酸还原酶活性，而在低光强下，增施其它形态的氮肥，尤其是铵态氮肥，反而会在一定程度上抑制玉米叶片和根系硝酸还原酶的活性。 (2)增施铵态氮肥能促进玉米幼苗对氮素的吸收和同化，而且玉米植株全氮含量和叶片硝态氮含量较低，植株总吸氮量较高，玉米地上部生物产量最高。而以硝态氮肥为氮源时，玉米叶片硝态氮含量和全氮含量最高。 (3)低光强下，灌水和施氮对玉米叶片硝酸还原酶活性的作用有限，而对玉米根系硝酸还原酶活性的影响显著，适当水分亏缺或增施氮肥均可显著地增加根系硝酸还原酶活性；高光强下，增加灌水对玉米叶片硝酸还原酶活性的促进作用大于根系，而增施氮肥对玉米叶片和根系硝酸还原酶活性的影响一致，但高氮和过量灌水会降低玉米叶片硝酸还原酶活性，严重抑制根系硝酸还原酶活性。 (4)光照有利于增加玉米叶片硝态氮的含量。适量施氮和灌水可降低玉米叶片硝态氮的含量；干旱或过量灌水均会增加玉米叶片硝态氮含量。 (5)高光强条件下，玉米根系和地上部生物产量明显高于低光强，而且根／冠比也较大。低光强下适当增加硝态氮肥施用量可提高玉米根系和地上部生物产量，对根／冠比影响较小，而增加铵态氮肥则明显降低了玉米根／冠比。 (6)适当减少灌水，可提高玉米的根／冠比；在高光照下，适当的水分亏缺能促进玉米根系的生长。 (7)提高光照强度可明显地提高玉米总吸氮量；在一定范围内增加灌水可增加玉米籽粒的总吸氮量，降低玉米茎叶的总吸氮量，提高玉米植株的总吸氮量；在一定施氮量范围内，干旱和过量灌水皆能降低玉米植株的总吸氮量；适量的增加氮肥施用量可提高玉米植株总吸氮量，而在土壤干旱的条件下，施氮量不宜过高。 (8)增施氮肥、增加灌水均能提高玉米生物产量，其增产效果主要受光照控制。而过量灌水和施肥，反而会降低玉米生物产量。更多还原

【Abstract】 Interaction of the plant growth with the factors of water, nitrogen and light is very closely. In order to provide theory basis and guidance for the agriculture production reasonably, the mechanism for the functions of water, nitrogen and light in the growth of plant need to be studied. In this thesis, effect of water, nitrogen and light on nitrate reductase activity, nitrite nitrogen, nitrogen content and biomass production in maize planted in pot and field experiments are discussed. The main results obtained in this study are as follows:(1) Nitrate reductase activity of maize grown in four different N-fertilizer sources was highest in leavers under high light and high fertilizer treatments, but it was lowest in roots under high light and low fertilizer treatments. The nitrate reductase activity of maize leaves and roots was higher with appropriate nitrate applications, but lower under low lighttreatments in other forms N-fertilizer sources especially ammonium fertilizer source.(2) Increasing the amount of ammonium fertilizer might enhance nitrogen uptake and assimilation in maize seedlings. Under the same conditions, the contents of nitrogen and nitrate of leaves in maize were lower, the amount nitrogen in maize was higher and the shoot biomass production was highest. In nitrate fertilizer sources, the contents of nitrogen and nitrate in maize were highest.(3) Under low light treatments, the nitrate reductase activity of maize leaves was only slightly affected, root nitrate reductase activity of maize was notably affected by the amount of water and nitrogen in soil. Under drought conditions and with a great of ammonium fertilizer application, the root nitrate reductase activity of maize was high. Under high light treatments, the nitrate reductase activity of maize leaves and roots were increased with the increase of the amount of irrigation water, but it reduced by axcessive irrigation water under the higher N-fertilizer treatments.(4) High light is useful to increase the leaves nitrate content in maize. The leaves nitrate content in maize was reduced under the appropriate amount of irrigation water and application of N-fertilizer, but it increased under the drought condition or axcessive irrigation water.(5) Under high light treatments, the shoot and root biomass production in maize were higher, and the root/shoot ratio was higher. Under lower light treatments, with the appropriate increase of the amount of application of nitrate fertilizer, the shoot and root biomass production in maize were increased and the root/shoot ratio was slightly affected.(6) The root/shoot ratio in maize was increased with the appropriate increase of the amount of irrigation water. Under high light treatments, the appropriate water efficiency made root grow well in maize.(7) The amount nitrogen in maize was increased with the increase of light. The amount nitrogen of seed in maize was increased and the amount nitrogen of stems and leaves in maize were reduced with the appropriate increase of the amount of irrigation water. The amount nitrogen in maize was reduced under the drought conditions or by axcessive irrigation water. The amount nitrogen in maize were increased with the appropriate increase of the amount of application of N-fertilizer, but under the drought conditions, were reduced by the great amount of application of N-fertilizer.(8) The biomass production in maize was increased with appropriate increase of the amount of irrigation water or application of N-fertilizer, affected notably by light, but reduced by axcessive irrigation water or application of N-fertilizer.更多还原