Tolerance and adaptation characteristics of sugar beet (Beta vulgaris L.) to low nitrogen supply

ABSTRACT

Nitrogen (N) is an essential element required for sugar beet growth. Sugar beets with low N (LN) tolerance and high N use efficiency are excellent materials for breeding. Here, we comprehensively evaluated the morphological and physiological responses of nine sugar beet genotypes to LN supply. It was found that 0.5 mmol·L⁻¹ N (LN) significantly influenced the performance of leaves and the topology of roots by reducing the bioproduction of chlorophyll a (Chl a) and soluble protein (SP) and the accumulation of N in leaves and roots (LNA and RNA), thus differentially restricting the growth (hypocotyl diameter, HD; root length, RL) and biomass (leaf and root fresh weight; LFW and RFW; leaf dry weight, LDW) of these sugar beets. Principal component and cluster analyses showed that 780016B/12 superior (F) exhibited excellent tolerance to LN; it had higher SOD activity (62.70%) and APX activity (188.92%) and a higher proline content (131.82%) than 92011 (G, LN sensitive). These attributes helped 780016B/12 superior (F) to better endure LN stress, and the morphology and N distribution changed to adapt to N deficiency, such that the root length increased by 112.48%, leaf area increased by 101.23%, and leaf nitrogen accumulation reached a peak of 14.13 g/plant. It seems that LN-tolerant genotypes increased their root length and surface area by reducing the difference in biomass, thereby expanding the contact between roots and soil, which was conducive to the absorption of nutrients (N) by sugar beets and helped distribute more assimilation products to the roots.

KEYWORDS:

• Sugar beet
• low nitrogen (LN)
• growth indexes
• root morphology
• antioxidant enzyme activity
• comprehensive evaluation

Disclosure statement

No potential conflict of interest was reported by the author(s).

Supplementary Material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/15592324.2022.2159155

Author contribution

Writing—original draft preparation: JL; validation: LX, XL, QY, WL; formal analysis: JL, DL, QW; data curation, JL, LX, XL; writing—review and editing: DL, WT, WX; supervision: DL, QW, WX. All authors have read and agreed to the published version of the manuscript.

Correction Statement

This article has been corrected with minor changes. These changes do not impact the academic content of the article.

Additional information

Funding

This work was supported by the National Sugar Industry Technology System Project(CARS-170102), the Sugar Beet Germplasm Resources Safe Preservation Program (19221878), the Innovative Training Plan for Young Talents in Heilongjiang Ordinary Undergraduate Colleges and Universities (UNPYSCT-2020), the Natural Science Foundation of Heilongjiang Province of China (LH2019C057), and the National Natural Science Foundation of China (31606229).