ABSTRACT
Responses of nitrogen metabolism, photosynthetic parameter and growth to nitrogen fertilization in Rumex patientia L. x Rumex tianschanicus Losinsk

Zengyang He1, 2, Jianfeng Zou2, 3, Xinyao Li1, 4, Tao Jiang2, Jianguo Zeng3*, and Miaofen Chen1, 2*
 
Edible grasses (Rumex patientia L. × Rumex tianschanicus Losinsk.) are highly prized as a superior food ingredient due to their abundant yields and rich protein content. Nevertheless, this particular crop lacks a symbiotic N fixation system, resulting in an equally significant requirement for N fertilizers. Nitrogen is a highly sought-after mineral ingredient that plays a constant role in the growth and development of plants. This study aimed to investigate the optimal N delivery for hydroponically cultivated leaf-eating grasses. The study included five different N concentration treatments: 45.53 (N1), 91.06 (N2), 136.59 (N3), 182.12 (N4), and 262.65 mg L-1 (N5). These treatments were used to assess the impact of varying N supply levels on the growth indexes, N utilization efficiency, and photosynthetic rate of phloem. The study observed that the growth indexes of leaf-eating grass, such as plant height, diameter, number of tillers, biomass, N buildup, and photosynthetic rate, exhibited a pattern of initially increasing and subsequently declining with higher N levels. Specifically, at a N concentration of 136.59 mg L-1 (N3), the indices reached the highest point with plant height of 23.18 cm, ground diameter of 6.06 mm, tiller number of 9.14, whole plant biomass of 1.10 g, whole plant N accumulation of 49.48 g, and N utilization of 19.92, which were significantly (P < 0.05) higher compared to other treatment levels. This optimal N level was favorable for promoting plant growth and contributing to the accumulation of proteins and other organic substances.
Keywords: Edible grass, growth index, N supply level, N efficiency, photosynthesis, seedling.
1Hunan Agricultural University, College of Horticulture, Changsha 410128, China.
2Hunan Agricultural University, Hunan Key Laboratory of Traditional Chinese Veterinary Medicine, Changsha, 410128, China.
3Hunan Agricultural University, College of Veterinary, Changsha 410128, China. 4Joyherb Biotechnology Co., Ltd., Changsha, 410128, China.
*Corresponding authors (zengjianguo@hunau.edu.cn, miaofen_Chen@hunau.edu.cn).