Nitrogen is an essential macronutrient required for plant growth. In this study, the relationships between plant growth, photosynthetic capability, chlorophyll fluorescence characteristics, and nitrogen forms in response to low-nitrogen stress were studied in tomatoes grafted with different nitrogen-use-efficiency tomato seedlings.
Using tomato plants grafted with different rootstocks, we found that, under low-nitrogen stress, plant growth, chlorophyll contents, net photosynthetic rate (Pn), maximal photochemical efficiency (Fv/Fm), the total nitrogen (TN) concentration, and nitrate reductase (NR) activity were significantly inhibited but that the ammonium-nitrogen (NH4+-N) content in the roots significantly increased. High-nitrogen-use-efficiency tomato grafted plants exhibited significantly enhanced plant growth but reduced Pn, Fv/Fm, TN content, and NR activity under low-nitrogen conditions compared to the grafted seedlings of the low-nitrogen-use-efficiency genotype.
In addition, tomato plants grafted onto high-nitrogen efficient rootstock presented reduced damage caused by excessive accumulation of NH4+-N in the roots under low-nitrogen stress. Our results indicate that tomato plants grafted onto high-nitrogen efficient rootstock presented enhanced absorption and utilization of nitrogen and maintained growth by promoting the use efficiency of light energy under low-nitrogen stress.
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Zhang, Zhihuan & Cao, Bili & Chen, Zijing & Xu, Kun. (2022). Grafting Enhances the Photosynthesis and Nitrogen Absorption of Tomato Plants Under Low-Nitrogen Stress. Journal of Plant Growth Regulation. 41. 10.1007/s00344-021-10414-2.