• ISSN 1008-505X
  • CN 11-3996/S
张珊珊, 张佳祺, 李银水, 代晶, 顾炽明, 杨璐, 胡文诗, 秦璐, 廖星. 硝铵供应比对油菜光合作用的影响[J]. 植物营养与肥料学报. DOI: 10.11674/zwyf.2023547
引用本文: 张珊珊, 张佳祺, 李银水, 代晶, 顾炽明, 杨璐, 胡文诗, 秦璐, 廖星. 硝铵供应比对油菜光合作用的影响[J]. 植物营养与肥料学报. DOI: 10.11674/zwyf.2023547
ZHANG Shan-shan, ZHANG Jia-qi, LI Yin-shui, DAI Jing, GU Chi-ming, YANG Lu, HU Wen-shi, QIN Lu, LIAO Xing. Effect of nitrate to ammonium ratio on photosynthesis of Brassica napus L.[J]. Journal of Plant Nutrition and Fertilizers. DOI: 10.11674/zwyf.2023547
Citation: ZHANG Shan-shan, ZHANG Jia-qi, LI Yin-shui, DAI Jing, GU Chi-ming, YANG Lu, HU Wen-shi, QIN Lu, LIAO Xing. Effect of nitrate to ammonium ratio on photosynthesis of Brassica napus L.[J]. Journal of Plant Nutrition and Fertilizers. DOI: 10.11674/zwyf.2023547

硝铵供应比对油菜光合作用的影响

Effect of nitrate to ammonium ratio on photosynthesis of Brassica napus L.

  • 摘要:
    目的 油菜是我国重要的油料作物,当氨态氮(NH4+-N)作为唯一氮源时,油菜的光合作用受到显著抑制,添加硝态氮(NO3-N)能显著缓解NH4+-N的抑制效应。探究不同硝铵配比对油菜叶片光合能力的影响,明确硝态氮调控油菜光合能力的生理机制,对优化施用氮肥形态,保障冬油菜扩面增产有重要意义。
    方法 利用水培试验方法,在高氮(8 mmol/L, HN)和低氮(1 mmol/L, LN)处理下,设置全硝、硝铵3∶1、硝铵1∶1、硝铵1∶3、全铵5个配合比例,在2处理15、20、25天时,取油菜样品,测定光合能力参数和生物量。利用光合限制模型分析硝铵比对光合速率的限制。
    结果 全铵配比的油菜在HN处理下第5天和LN处理下第7天开始出现枯黄症状,直至18天全部死亡,在2处理15天后,植株生物量差异显著。与硝铵3∶1相比,硝铵1∶1配比生物量分别降低了5.6%~61.3%,硝铵1∶3配比下降了6.9~110.6%。同一氮水平下,不同硝铵比例叶片全氮含量无显著差异,然而硝态氮和铵态氮含量差异显著,硝铵3∶1配比叶片硝态氮含量显著高于硝铵1∶1和1∶3配比,分别高出91.7~292.7%和130.0~1255.0%;而叶片铵态氮含量在生长后期以硝铵1∶3配比显著高于硝铵3∶1和全硝配比,分别高出52.6~53.3%和61.1~76.9%。硝态氮添加显著提高叶片净光合速率(A),硝铵3∶1配比A最高,较硝铵1∶1和1∶3 配比A显著提高了16.7~50.3%;硝铵3∶1配比显著提高了最大净光合速率(Amax)、最大羧化速率(Vcmax)、最大电子传递速率(Jmax)和叶肉导度(gm),分别提高了6.8~107.4%、9.2~79.5%、50.5~115.8%和8.6~134.8%。A随叶片硝态氮浓度和硝态铵态氮含量比值增加而增加,在硝态氮含量超过120.2~151.2 μg/g,比值超过2.6~3.2后,不再显著变化。通过光合限制模型分析,硝态氮添加提高油菜光合速率是通过降低生化限制和叶肉导度限制。
    结论 适当提高油菜氮肥的硝铵比可促进叶片的gmVcmax,从而提高叶片光合能力和植株生物量。氮源中铵超过一半后抑制油菜的光合作用,甚至导致油菜不能完成生命周期,而100%硝态氮也不利于油菜的光合作用。

     

    Abstract:
    Objectives Oilseed rape (Brassica napus L.) is the third largest oil crop in the world. The growth of oilseed rape is strongly inhibited by the pure NH4+-N supply. We explored the effects of nitrate to ammonium ratios on the photosynthetic capacity of oilseed rape, to optimize nitrogen forms and increase yield of winter oilseed rape.
    Methods A hydroponic culture method was used for the research. High and low N nutrition solution were prepared by regulating total N concentrations at 8 mmol (HN) and 1 mmol (LN). The N source treatments in the nutrient solutions included total nitrate (TN), total ammonium (TA), and nitrate to ammonium ratio of 3∶1 (3N1A), 1∶1 (1N1A), and 1∶3 (1N3A), respectively. At the 15, 20 and 25 days of treatment, the photosynthetic parameters of seedling leaves were monitored, and the rapeseed seedlings were harvested for the investigation of N content and biomass. The limitation of N forms was expatiated by photosynthetic restriction model.
    Results The seedlings in TA treatment started to wither and became yellowing since 5 days under HN and 7 days under LN treatment, and died completely at 18 days of treatment. Compared with 3N1A, 1N1A and 1N3A treatments decreased the biomass by 5.6%−61.3% and 6.9%−110.6%, respectively. Under the same N level, the three nitrate to ammonium ratio treatments were close in leaf total N content, but significantly different in NO3-N and NH4+-N contents, and the leaves contained 91.7%−292.7% and 130.0%−1255.0% higher NO3-N content in 3N1A treatment than in 1N1A and 1N1A treatment, and 52.6−53.3% and 61.1-76.9% higher NH4+-N content than in 3N1A and TN treatment, respectively. The supply of NO3-N enhanced the net photosynthetic rate (A) significantly, with the highest increase in 3N1A treatment which was 16.7%−50.3% higher than 1N1A and 1N3A treatment. 3N1A treatment significantly increased the maximum net photosynthetic rate (Amax), maximum carboxylation rate (Vcmax), maximum electron transfer rate (Jmax) and mesophyll conductance (gm), and the values were 6.8%−107.4%, 9.2%−79.5%, 50.5%−115.8% and 8.6%−134.8% higher than those of 1N1A and 1N3A treatment, respectively. The leaf photosynthetic rate did not stop rising with enhanced NO3-N to NH4+-N ratio until that the leaf NO3-N content exceeded 120.2−151.2 μg/g and the NO3-N to NH4+-N ratio in leaf exceeded 2.6−3.2. The photosynthetic restriction model showed that the addition of NO3-N promoted A by reducing BL and MCL.
    Conclusion sRelatively high NO3-N to NH4+-N ratio in leaves accelerates gm and Vcmax, promotes net photosynthetic rate, and biomass. High ammonia ratio inhibits the growth, and pure ammonia supply may even leads to death of the seedlings. And pure nitrate source is not good for the efficient photosynthesis as well.

     

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