Effect of nitrogen form and nitrogen supply level on maize (Zea mays L.) biology and photosynthesis characteristics under water-logging stress at seedling stage | 单一铵、硝营养对苗期淹水胁迫玉米光合与生物学性状的影响

Chinese. 研究NH+4-N和NO-3-N及其不同供氮水平对苗期玉米抗淹水胁迫的影响，为采用氮营养调控途径提高玉米的抗涝性提供理论依据。采用室内砂砾培养及模拟淹水胁迫的方法，研究2个不同品种玉米（利民15和皖玉9号），分别在苗期供应NH+4-N和NO-3-N 2种形态氮素以及高（7 mmol/L ）、低（3 mmol/L ）氮2个氮素水平时，其光合与生长对淹水胁迫的响应。在非淹水胁迫条件下，在高氮水平下2个玉米品种不同部位的生物量、株高、茎横截面积、根体积、光合速率、叶绿素含量和叶面积均相对高于低氮水平。但在淹水胁迫条件下，当NH+4-N供氮水平较低（3 mmol/L）时，2个品种玉米在苗期均表现相对较强的抗涝性；但在NO-3-N营养条件下，供氮水平较高（7 mmol/L）时，表现相对较强的抗涝性。即分别在3 mmol/L NH+4-N、7 mmol/L NO-3-N条件下，利民15和皖玉9号在淹水胁迫条件下可以维持相对较高的茎横截面积、根体积、光合速率、叶绿素含量和叶面积。在不同氮素营养条件下，苗期不同品种玉米抗涝性强弱随氮素供应形态和供应水平而异。

English. The aim of study was to provide a theoretical basis on water-logging tolerance enhancement by using optimal nitrogen supply. Flooding or water-logging is an abiotic stress as major limits to agriculture in many regions in south China. Success or failure of crops in many arable farmlands can also be determined by frequency and the extent of flooding. Therefore, it is important to investigate methods associated with enhancing water-logging tolerance, and to use them in maize cultivation. In general, maize plants were less tolerant of water-logging at the early growth stages. Biology and photosynthesis response of two maize cultivars at seedling stage to nitrogen forms (ammonium and nitrate) and nitrogen levels (3 mmol/L and 7 mmol/L) under water-logging stress were studied by using nutrient solution culture. The results showed that, biomass of different parts, plant height, stem cross section area, roots volume, photosynthesis rate, chlorophyll content and leaf area of maize plants supplied with high nitrogen level (7 mmol/L) was higher than those supplied with low nitrogen level (3 mmol/L) under non water-logging stress condition. Water-logging tolerance of maize plants supplied with low nitrogen level was higher than those supplied with high nitrogen level under ammonium nutrition, while the tolerance of maize plants supplied with high nitrogen level was higher than those supplied with low nitrogen level under nitrate nutrition. Higher tolerance of maize plants to water logging stress appears to maintain higher biomass of different parts, photosynthesis rate, etc. Therefore, response to water-logging stress varied considerably depending on genotypes and nitrogen supply, either nitrogen forms or nitrogen levels.