Growth, Quality, and Nitrogen Assimilation in Response to High Ammonium or Nitrate Supply in Cabbage (Brassica campestris L.) and Lettuce (Lactuca sativa L.)

Agronomy

Jinnan Song¹  Byoung Ryong Jeong¹  Jingli Yang¹ 

[1] Department of Horticulture, Division of Applied Life Science (BK21 Four Program), Graduate School of Gyeongsang National University, Jinju 52828, Korea;

关键词: nitrogen metabolism;    ammonium toxicity;    photosynthetic capacity;    carbohydrate;    nitrate reductase (NR);    nitrite reductase (NIR);   

DOI  :  10.3390/agronomy11122556

来源: DOAJ

【 摘 要 】

Plants grow better when they are supplied with a combination of ammonium (NH₄⁺) and nitrate (NO₃⁻) than when either one is supplied as the sole N (nitrogen) source. However, the effects of N forms on N metabolism and major N assimilation enzymes in different plants, especially vegetables, are largely neglected. This study was conducted on two plants with distinct NH₄⁺ tolerances to compare the responses of two popular leafy vegetables, Korean cabbage (Brassica campestris L.) ‘Ssamchu’ and lettuce (Lactuca sativa L.) ‘Caesar green’, to the N source. To this end, plant growth and quality, photosynthesis, carbohydrate, N contents (in the forms of NO₃⁻, NO₂⁻, NH₄⁺, total protein), and key N assimilation-related enzyme (NR, NIR, GS, GDH) activities were investigated. When plants were subjected to one of three NH₄⁺:NO₃⁻ regimes, 0:100, 50:50, or 100:0, lettuce was relatively more tolerant while cabbage was extremely sensitive to high NH₄⁺. Both plants benefited more from being grown with 50:50 NH₄⁺:NO₃⁻, as evidenced by the best growth performance, ameliorated photosynthesis, and enriched carbohydrate (C) stock content. In addition, as compared to cabbage, the GS and GDH activities were reinforced in lettuce in response to an increasing external NH₄⁺ level, resulting in low NH₄⁺ accumulation. Our findings suggested that boosting or maintaining high GS and GDH activities is an important strategy for the ammonium tolerance in vegetables.

【 授权许可】

Unknown