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.

Estimating Chlorophyll Content, Production, and Quality of Sugar Beet under Various Nitrogen Levels Using Machine Learning Models and Novel Spectral Indices

“…However, it also has negative effects on root quality by raising harmful nitrogen levels in the root and lowering the SC at harvest. Similar findings have been reported in earlier studies [6][7][8]87]. These studies have found that an optimal rate of N fertilizer is crucial for achieving the maximum RY and optimum SC.…”

Seepage Prediction Model for Roller-Compacted Concrete Dam Using Support Vector Regression and Hybrid Parameter Optimization

“…PCA is a dimensionality reduction technique that uses a linear transformation to transform original high-dimensional data into several variables in a lower mutually exclusive dimension [49,50]. Compared with other dimension-reduction techniques, the greatest possible amount of original information can be obtained using PCA [51,52]. Therefore, the PCA method was adopted in this study to reduce the dimensionality of the factors after GRA as well as to shorten the calculation time of the models developed subsequently.…”

Low nitrogen stress-induced transcriptome changes revealed the molecular response and tolerance characteristics in maintaining the C/N balance of sugar beet (Beta vulgaris L.)

“…Under stress conditions, they exhibit complex and diverse responses to abiotic stresses by altering gene and protein expression as well as primary and secondary metabolites (Bhatotia et al, 2015;Onaga and Wydra, 2016). During nitrogen starvation, various defective response genes act to maintain plant survival by altering root architecture (Li et al, 2023), improving nitrogen assimilation (Imamura et al, 2009), and increasing lignin content (Tian et al, 2022). The phenylpropanoid metabolic pathway is closely related to lignin synthesis (Cong et al, 2013), whose pathway is closely related to photosynthetic carbon utilization (Zhang et al, 2018c).…”

“…In recent years, continuous progress in sequencing technologies has provided an efficient way to identify functional genes and study their regulatory mechanisms, and the sugar beet genome has also been extensively developed (Dohm et al, 2014;Wascher et al, 2022). Previously, we explored the tolerance and adaptation characteristics of different sugar beet germplasms at both morphological and physiological levels under low N (LN) environments (Li et al, 2022;Li et al, 2023). However, there are still some important phenomena in this process that need to be explained through relevant molecular regulation.…”