scholarly journals Variations in Nitrogen Metabolism are Closely Linked with Nitrogen Uptake and Utilization Efficiency in Cotton Genotypes under Various Nitrogen Supplies

Plants ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 250 ◽  
Author(s):  
Asif Iqbal ◽  
Qiang Dong ◽  
Xiangru Wang ◽  
Huiping Gui ◽  
Hengheng Zhang ◽  
...  

Cotton production is highly sensitive to nitrogen (N) fertilization, whose excessive use is responsible for human and environmental problems. Lowering N supply together with the selection of N-efficient genotypes, more able to uptake, utilize, and remobilize the available N, could be a challenge to maintain high cotton production sustainably. The current study aimed to explore the intraspecific variation among four cotton genotypes in response to various N supplies, in order to identify the most distinct N-efficient genotypes and their nitrogen use efficiency (NUE)-related traits in hydroponic culture. On the basis of shoot dry matter, CCRI-69 and XLZ-30 were identified as N-efficient and N-inefficient genotypes, respectively, and these results were confirmed by their contrasting N metabolism, uptake (NUpE), and utilization efficiency (NUtE). Overall, our results indicated the key role of shoot glutamine synthetase (GS) and root total soluble protein in NUtE. Conversely, tissue N concentration and N-metabolizing enzymes were considered as the key traits in conferring high NUpE. The remobilization of N from the shoot to roots by high shoot GS activity may be a strategy to enhance root total soluble protein, which improves root growth for N uptake and NUE. In future, multi-omics studies will be employed to focus on the key genes and pathways involved in N metabolism and their role in improving NUE.

PLoS ONE ◽  
2021 ◽  
Vol 16 (1) ◽  
pp. e0244996
Author(s):  
Xiaoxi Zhen ◽  
Naimeng Zheng ◽  
Jinlei Yu ◽  
Congyuan Bi ◽  
Fan Xu

Autophagy, a conserved cellular process in eukaryotes, has evolved to a sophisticated process to dispose of intracellular constituents and plays important roles in plant development, metabolism, and efficient nutrients remobilization under suboptimal nutrients conditions. Here, we show that OsATG8b, an AUTOPHAGY-RELATED8 (ATG8) gene in rice, was highly induced by nitrogen (N) starvation. Elevated expression of OsATG8b significantly increased ATG8 lipidation, autophagic flux, and grain yield in rice under both sufficient and deficient N conditions. Overexpressing of OsATG8b could greatly increase the activities of enzymes related to N metabolism. Intriguingly, the 15N-labeling assay further revealed that more N was remobilized to seeds in OsATG8b-overexpressing rice, which significantly increased the N remobilization efficiency (NRE), N harvest index, N utilization efficiency (NUE), and N uptake efficiency (NUpE). Conversely, the osatg8b knock-out mutants had the opposite results on these characters. The substantial transcriptional changes of the overexpressed transgenic lines indicated the presence of complex signaling to developmental, metabolic process, and hormone, etc. Excitingly, the transgenic rice under different backgrounds all similarly be boosted in yield and NUE with OsATG8b overexpression. This work provides an excellent candidate gene for improving N remobilization, utilization, and yield in crops simultaneously.


2020 ◽  
Vol 13 (3) ◽  
pp. 38
Author(s):  
C. L. R. Santos ◽  
J. O. Cazetta ◽  
L. M. Saran ◽  
M. F. Moraes ◽  
C. F. Silva

Intrinsic genetic potential of each cultivar of sugarcane may determine the absorption intensity and nitrogen assimilation. It is possible to occur a lower expression of the productive potential by limitations related to low nitrate reductase (NR) activity, since this enzyme is "key" of the N metabolism. The objectives were to compare cultivars of sugarcane as the level of NR activity and its relationship to productive and nutritional variables. The experiment was conducted under condition of a greenhouse, where were grown ten sugarcane cultivars in pots of 4 dm3, filled with sand and vermiculite plus nutrients as indicated for the crop. The variables evaluated were: plant height, NR activity, dry matter (shoot and roots), N content and N accumulation and N uptake and utilization efficiency, moreover, the correlation between the variables was evaluated. The results showed that NR activity varies with the cultivar and further, that NR activity in sugarcane leaves does not correlate with the N uptake efficiency, but is positively correlated with N content and negatively with N utilization efficiency. The NR activity is not a good physiological parameter to discriminate N efficient use sugarcane genotypes


Agronomy ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1187
Author(s):  
Yongjian Sun ◽  
Yuanyuan Sun ◽  
Fengjun Yan ◽  
Yue Li ◽  
Yunxia Wu ◽  
...  

We sought to explore the role of postanthesis carbon and nitrogen (C-N) metabolism of hybrid rice in increasing yield and nitrogen utilization efficiency (NUE). We used the 13C and 15N dual-isotope tracer method and physiological/biochemical analysis and established different irrigation and nitrogen fertilization (W-N) regimes to investigate the relationship of C-N metabolism characteristics, yield, and NUE. The results showed that W-N regimes had significant effects on postanthesis absorption and translocation of N and photosynthate, yield and NUE. Aerobic irrigation combined with the N fertilization regime 30% base, 30% tillering, 40% booting was the best W-N coupling regime for rice yield and NUE increase. The regime enhanced flag leaf photosynthesis rate and the activities of ribulose 1,5-diphosphate carboxylase/oxygenase (RuBPCase), glutamine synthetase (GS), and other key enzymes of C-N metabolism, and improved the total accumulations of photoassimilates (0.97–21.57 mg 13C plant−1) and N (1.55–23.36 mg 15N plant−1), respectively. Correlation analysis showed that, under the W-N interaction, C-N metabolism enzymes promoted the positive synergistic effect between 13C and 15N accumulation in panicles (r = 0.825). In addition, the change in C/N ratio can be used as an indicator of the simultaneous improvement in yield and NUE in hybrid rice.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yan Tan ◽  
Qiang Chai ◽  
Guang Li ◽  
Cai Zhao ◽  
Aizhong Yu ◽  
...  

AbstractCrop yield is limited by water and nitrogen (N) availability. However, in Hexi Corridor of northwestern China, water scarcity and excessive fertilizer N in wheat (Triticum aestivum L.) production causes serious conflicts between water and N supply and crop demand. A field experiment was conducted from 2016 to 2018 to evaluate whether reducing of irrigation and fertilizer N will reduce grain yield of wheat. There were two irrigation quotas (192 and 240 mm) and three fertilizer N rates (135, 180, and 225 kg N ha−1). The results showed that reducing irrigation to 192 mm and N rate to 180 kg N ha−1 reduced water uptake, water uptake efficiency, and N uptake of spring wheat as compared to local practice (i.e., 240 mm irrigation and 225 kg N ha−1 fertilizer). Whereas, it improved water and N utilization efficiency, and water and N productivity. Consequently, the irrigation and N rate reduced treatment achieved the same quantity of grain yield as local practice. The path analysis showed that interaction effect between irrigation and N fertilization may attributable to the improvement of grain yield with lower irrigation and N rate. The enhanced water and N utilization allows us to conclude that irrigation quota at 192 mm coupled with fertilizer N rate at 180 kg N ha−1 can be used as an efficient practice for wheat production in arid irrigation areas.


2011 ◽  
Vol 150 (4) ◽  
pp. 460-472 ◽  
Author(s):  
E. WHITE

SUMMARYA detailed study of nitrogen use efficiency (NUE) and its components in three cultivars of winter wheat, Hereward, Rialto and Riband was undertaken in cultivar trials conducted in Northern Ireland in 1998 and 1999. Yield, grain N concentration, harvest index (HI), nitrogen harvest index (NHI), N uptake efficiency (NUpE), total N uptake, grain N off-take, N utilization efficiency (NUtE) and NUE itself all showed significant variation between sites. Cvars Hereward and Rialto had similar mean values across all the sites for many of the characteristics, with Riband usually differing. In all but one characteristic, grain N concentration, the responses of the three cultivars varied significantly from trial to trial and this, along with the substantial variation between sites, indicates that genetic control of the characteristics is partial. The amount of N applied as fertilizer accounted for little of the variation among the trials with weak associations for NUpE, which decreased, and grain yield, which increased with increasing fertilizer N. Neither grain yield nor NUE was associated with the amount of N taken up by the crop, but grain N concentration increased and NUtE decreased significantly. HI and NHI differed significantly among the cultivars, diverging at higher N uptakes, with Hereward and Rialto being similar and distinctly different from Riband. Grain yield was only weakly associated with NUpE but was strongly and positively associated with NUtE and NUE. The strong negative association between NUtE and NUpE highlights the potential and the urgency of understanding factors influencing uptake of nitrogen by crops. The extent of the non-genetic, i.e. environmental and management, variation in the characteristics, along with the relative similarity of the cultivar means, throws up a challenge to plant breeders, agronomists and researchers wishing to improve NUE genetically and through management. As with yield and other characteristics, a large number of trials will be required to identify consistent differences in NUE among cultivars. Thus, while mechanisms underlying NUE, NUpE and NUtE need to be understood, the possibility of using the HGCA UK Recommended List database to investigate NUE and identify cultivars with improved NUE should also be considered. Since in each of the HGCA trials cultivars have access to the same available N, and since grain yield=available N×NUE, grain yield itself is a surrogate for the NUE of cultivars. Grain N concentration is only determined in a few cultivars at present but could be used as an indicator of optimal N availability in individual trials, allowing variation in NUE of cultivars in response to agro-ecological factors on NUE to be studied.


HortScience ◽  
2002 ◽  
Vol 37 (7) ◽  
pp. 1061-1064 ◽  
Author(s):  
S.J. Breschini ◽  
T.K. Hartz

Trials were conducted in 15 commercial fields in the central coast region of California in 1999 and 2000 to evaluate the use of presidedress soil nitrate testing (PSNT) to determine sidedress N requirements for production of iceberg and romaine lettuce (Lactuca sativa L.). In each field a large plot (0.2-1.2 ha) was established in which sidedress N application was based on presidedress soil NO3-N concentration. Prior to each sidedress N application scheduled by the cooperating growers, a composite soil sample (top 30 cm) was collected and analyzed for NO3-N. No fertilizer was applied in the PSNT plot at that sidedressing if NO3-N was >20 mg·kg-1; if NO3-N was lower than that threshold, only enough N was applied to increase soil available N to ≈20 mg·kg-1. The productivity and N status of PSNT plots were compared to adjacent plots receiving the growers' standard N fertilization. Cooperating growers applied a seasonal average of 257 kg·ha-1 N, including one to three sidedressings containing 194 kg·ha-1 N. Sidedressing based on PSNT decreased total seasonal and sidedress N application by an average of 43% and 57%, respectively. The majority of the N savings achieved with PSNT occurred at the first sidedressing. There was no significant difference between PSNT and grower N management across fields in lettuce yield or postharvest quality, and only small differences in crop N uptake. At harvest, PSNT plots had on average 8 mg·kg-1 lower residual NO3-N in the top 90 cm of soil than the grower fertilization rate plots, indicating a substantial reduction in subsequent NO3-N leaching hazard. We conclude that PSNT is a reliable management tool that can substantially reduce unnecessary N fertilization in lettuce production.


Agronomy ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 689 ◽  
Author(s):  
Asif Iqbal ◽  
Huiping Gui ◽  
Hengheng Zhang ◽  
Xiangru Wang ◽  
Nianchang Pang ◽  
...  

Low phosphorus (P) availability is a major constraint for cotton production. Consequently, P-efficient genotypes can improve productivity under conditions where the higher application of P is not economical. This study was conducted to characterize cotton genotypes for P-use efficiency under various P concentrations (0, 10, 20, 40, 80, and 500 μM KH2PO4). The results showed large genotypic variation in five selected traits, such as root dry weight, shoot dry weight, photosynthetic activity, P-utilization efficiency, and P-uptake efficiency. Based on these five selected traits, the genotypes were grouped into three main classes as efficient, moderate efficient, and inefficient genotypes as proposed by different researchers. Most of the genotypes behaved in a similar pattern under different P concentrations. Among the genotypes, Xinluzao-49 and Xinluzao-48 were considered as P efficient while CCRI-64 and Yumian-21 as inefficient genotypes. However, the rest of the genotypes were considered as moderately P efficient. The results prove that a large genetic potential exists in cotton genotypes for P-use efficiency, and the use of P-efficient genotypes for cultivation will reduce the application of phosphatic fertilizers. Furthermore, the use of P-efficient genotypes will improve cotton breeding activities and help in improving the environmental sustainability of cotton production.


Plants ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 1758
Author(s):  
Ioanna Kakabouki ◽  
Antonios Mavroeidis ◽  
Alexandros Tataridas ◽  
Ioannis Roussis ◽  
Nikolaos Katsenios ◽  
...  

An increasing interest has been reported regarding the reintroduction of flax in the Mediterranean region. The aim of this present study was to evaluate the effects of nitrogen (N) fertilization on the performance of flax cv. Everest, under Mediterranean climate conditions. A two-year study was carried out in 2018–2019, in Western Greece. The experiment was set-up in a randomized complete block design with four replications and six treatments of different N fertilization rates (0, 20, 30, 40, 50, and 60 kg N ha−1). Measurements included plant biomass, the leaf area index (LAI), the yield, and the Growth Degree Days (GDDs) required for full seed maturity. The N uptake of flax was also evaluated utilizing the Nitrogen Harvesting (NHI) and Nitrogen Utilization Efficiency (NUtE) indices. Although the highest fertilization rate (60N) increased the yield by 35.4% (2018) and 23.1% (2019), a GDDs and N indices assessment revealed that it noted the lowest efficiency and may lead to significant yield losses, as it significantly prolonged the crop cycle. On the contrary, even though fertilization rates of 20 and 30 kg N ha−1 increased the yield only by 7% and 15% (on average), they were more efficient, and prolonged the crop cycle less (compared to 60N).


Agronomy ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1295
Author(s):  
Ahossi Patrice Koua ◽  
Mirza Majid Baig ◽  
Benedict Chijioke Oyiga ◽  
Jens Léon ◽  
Agim Ballvora

Nitrogen (N) is a vital component of crop production. Wheat yield varies significantly under different soil available N. Knowing how wheat responds to or interacts with N to produce grains is essential in the selection of N use efficient cultivars. We assessed in this study variations among wheat genotypes for productivity-related traits under three cropping systems (CS), high-nitrogen with fungicide (HN-WF), high-nitrogen without fungicide (HN-NF) and low-nitrogen without fungicide (LN-NF) in the 2015, 2016 and 2017 seasons. ANOVA results showed genotypes, CS, and their interactions significantly affected agronomic traits. Grain yield (GY) increased with higher leaf chlorophyll content, importantly under CS without N and fungicide supply. Yellow rust disease reduced the GY by 20% and 28% in 2015 and 2016, respectively. Moreover, averaged over growing seasons, GY was increased by 23.78% under CS with N supply, while it was greatly increased, by 52.84%, under CS with both N and fungicide application, indicating a synergistic effect of N and fungicide on GY. Fungicide supply greatly improved the crop ability to accumulate N during grain filling, and hence the grain protein content. Recently released cultivars outperformed the older ones in most agronomic traits including GY. Genotype performance and stability analysis for GY production showed differences in their stability levels under the three CS. The synergistic effect of nitrogen and fungicide on grain yield (GY) and the differences in yield stability levels of recently released wheat cultivars across three CS found in this study suggest that resource use efficiency can be improved via cultivar selection for targeted CS.


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