Genotype differences in photosynthetic characteristics and nitrogen efficiency of new-type oilseed rape responding to low nitrogen stress

2014 ◽  
Vol 153 (6) ◽  
pp. 1030-1043 ◽  
Author(s):  
G. L. WANG ◽  
G. D. DING ◽  
F. S. XU ◽  
H. M. CAI ◽  
J. ZOU ◽  
...  

SUMMARYNew-type oilseed rape (Brassica napus, ArArCcCc) with introgressed exotic subgenomic components from Brassica rapa (ArAr) and Brassica carinata (BcBcCcCc) showed strong heterosis in both vegetative and reproductive growth. The aim of the current study was to analyse the tolerance of the new-type B. napus with different exotic subgenomic contents to low nitrogen (N) stress. Under hydroponic culture and pot experiments, root system parameters, photosynthetic parameters, relative chlorophyll concentration (SPAD values), biomass, seed yield, seed yield components, N concentration and expressions of genes involved in N transport and assimilation were determined with two new-type B. napus genotypes (N-efficient genotype D4-15 and N-inefficient genotype D1-1) under high-N and low-N levels. Furthermore, N accumulation, N transfer efficiency and N use efficiency (NUE) were analysed in the two genotypes. The hydroponic and potted growth tests showed consistent characteristics in N uptake and utilization efficiency at the seedling stage, and N-efficient genotype (D4-15) showed better growth phenotypes across cultured conditions and N levels. Under the low-N condition, D4-15 produced a larger root system and accumulated more N, and had higher N transfer efficiency and NUE than D1-1. Moreover, D4-15 had significantly higher photosynthetic parameters, photosynthetic NUE and expression levels of the N transporter genes, BnNRT1·1, BnNRT2·5, BnNRT2·7 and BnAMT1·1, in roots or leaves, as well as higher seed yield than that of D1-1 under low-N supply. These results indicated that the N-efficient new-type B. napus D4-15 possessed excellent adaptability to low-N stress, which may be attributed to the highly introgressed exotic subgenomic components from B. rapa and B. carinata, suggesting the possibility of identifying high-nutrient-efficiency germplasm from inter-specific hybrids.

Agronomy ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1183 ◽  
Author(s):  
Yangyang Zhang ◽  
Piaopiao Lu ◽  
Tao Ren ◽  
Jianwei Lu ◽  
Li Wang

Cultivation of winter oilseed rape hybrids has been introduced as a promising solution to improve the nitrogen use efficiency (NUE) and to reduce the large N balance surpluses in this crop. To achieve a better understanding of the underlying physiological mechanisms, field experiments were conducted over two years to investigate the dynamics of growth and N capture in an oilseed rape hybrid and its parental lines under both low (0 kg ha−1) and high (180 kg ha−1) N supply. The results showed that the dynamic trajectories of crop growth and N capture could be accurately characterized by logistic equation using growing degree days as the independent variable. At both N rates, the oilseed rape hybrid outperformed the parental lines in seed yield and aboveground biomass accumulation, which was more closely associated with the longer duration (td) of the rapid growth period (RGP), than with the higher maximum growth rate (vm). N uptake was the main factor driving genotypic variation in seed yield, with an increasing importance of N utilization efficiency at high N supply. The hybrid had significantly higher N uptake than the parental lines at both low and high N supply, because of larger vm for N accumulation during the RGP, which may present a scope for genetically improving NUE in oilseed rape. High N application enhanced crop biomass production and N accumulation, as a result of prolonged td and larger vm during the RGP. The initiation of RGP for N accumulation occurred after overwinter period, which could not be accelerated by high N supply, suggesting rational distribution of N fertilizer with reduced basal dose. However, larger amounts in spring would be beneficial for a better synchronization to crop N demand with lower environmental risks.


2013 ◽  
Vol 153 (1) ◽  
pp. 42-55 ◽  
Author(s):  
C. A. WHITE ◽  
S. E. ROQUES ◽  
P. M. BERRY

SUMMARYThe aim of the present study was to evaluate the effects on yield, oil concentration and nitrogen (N) uptake efficiency of N fertilizer applied to the foliage of oilseed rape during and soon after flowering. Four field experiments were conducted in the UK during the 2008/09 and 2009/10 seasons which investigated six rates of soil-applied N (ammonium nitrate) ranging from 0 to 280 or 320 kg N/ha with each treatment followed by 0 or 40 kg/ha of foliar N applied as a solution of urea at the end of flowering. Each experiment also investigated five rates of foliar N ranging from 0 to 120 kg N/ha applied at the end of flowering and five timings of foliar N (40 kg N/ha) from mid-flowering to 2 weeks after the end of flowering.Foliar N at 40 kg N/ha applied at the end of flowering significantly increased the seed yield in three of the four experiments. The seed yield increase across all four experiments was 0·25 t/ha (range of 0–0·41 t/ha). In two experiments, the increase in seed yield in response to foliar N occurred irrespective of whether it followed sub-optimal or super-optimal rates of soil-applied N; in one experiment there was a greater response at sub-optimal soil-applied N rates. The foliar N treatment reduced the seed oil concentration by 11 g/kg and increased seed protein concentration by 11 g/kg. Similar yield responses were observed for foliar N applications between mid-flowering and 2 weeks after the end of flowering. The efficiency with which foliar N was taken up into the plant varied between 0 and 100% with an average uptake efficiency across the four experiments of 61%.


2015 ◽  
Vol 179 ◽  
pp. 1-5 ◽  
Author(s):  
Abdullah Ulas ◽  
Torsten Behrens ◽  
Franz Wiesler ◽  
Walter J. Horst ◽  
Gunda Schulte auf’m Erley
Keyword(s):  

2001 ◽  
Vol 1 ◽  
pp. 61-69 ◽  
Author(s):  
Franz Weisler ◽  
Torsten Behrens ◽  
Walter J. Horst

To improve nitrogen (N) efficiency in agriculture, integrated N management strategies that take into consideration improved fertilizer, soil, and crop management practices are necessary. This paper reports results of field experiments in which maize (Zea mays L.) and oilseed rape (Brassica napus L.) cultivars were compared with respect to their agronomic N efficiency (yield at a given N supply), N uptake efficiency (N accumulation at a given N supply), and N utilization efficiency (dry matter yield per unit N taken up by the plant). Under conditions of high N supply, significant differences among maize cultivars were found in shoot N uptake, soil nitrate depletion during the growing season, and the related losses of nitrate through leaching after the growing season. Experiments under conditions of reduced N supply indicated a considerable genotypic variation in reproductive yield formation of both maize and oilseed rape. High agronomic efficiency was achieved by a combination of high uptake and utilization efficiency (maize), or exclusively by high uptake efficiency (rape). N-efficient cultivars of both crops were characterized by maintenance of a relatively high N-uptake activity during the reproductive growth phase. In rape this trait was linked with leaf area and photosynthetic activity of leaves. We conclude that growing of N-efficient cultivars may serve as an important element of integrated nutrient management strategies in both low- and high-input agriculture.


2020 ◽  
pp. 76-85
Author(s):  
Olha Matsera

In the conditions of the Right-Bank Forest-Steppe, the cultivation of winter rapeseed crops after winter wheat usually leads to a delay in sowing the latter and deterioration of autumn plant development. Based on data from a field experiment conducted in 2016/2017, 2017/2018 and 2018/2019, the aim of this study was to investigate how sowing delay affects seed yield, nitrogen uptake by seeds and significant efficiency of nitrogen use by winter rape plants; to check the ability of autumn and spring application of nitrogen fertilizers to compensate for the negative impact of delays in sowing crops; and estimate the minimum autumn development for optimal seed yield. To solve the set tasks, a combination of four sowing dates (from the first week of August to the third week of September) and four autumn nitrogen applications (0, 30, 60 and 90 kg / ha per year) was fixed. In each of these 16 variants, nitrogen application was performed 5 times in the spring (0/0, 40/40, 80/80, 120/120, 140/140 kg / ha, etc.) in order to estimate the individual nitrogen reaction curves. Nitrogen accumulation by aboveground mass of plants in autumn, seed yield and nitrogen uptake by seeds were determined. It was found that sowing the crop after mid-September significantly reduced yields. Application of nitrogen fertilizers in autumn in the amount of at least 30 kg / ha per year increased the yield and absorption of nitrogen seeds without any significant interaction with the sowing period and spring application of nitrogen fertilizers. Increasing the dose of spring fertilizer application to 130 kg / ha increased seed yield. Nitrogen utilization efficiency decreased with increasing application rate when winter oilseed rape plants used nitrogen applied in the fall to a lesser extent than in the spring. In order to achieve high yields, it was necessary for the above-ground mass of plants to absorb nitrogen at the level of at least 10-15 kg / ha at the end of the autumn vegetation. From an ecological point of view, the optimal autumn development of plants should be achieved by choosing an adequate sowing date, rather than using additional nitrogen in autumn.


1998 ◽  
Vol 130 (2) ◽  
pp. 165-172 ◽  
Author(s):  
K. SIELING ◽  
H. SCHRÖDER ◽  
H. HANUS

In NW Europe, autumn-grown oilseed rape normally receives nitrogen (N) in autumn as seedbed N and in the spring as a split application at the beginning of growth and at stem elongation. In the growing seasons 1990/91 to 1992/93, the effects of slurry and mineral N fertilization on yield, N uptake by the seed and apparent N-use efficiency (NUE) by oilseed rape (Brassica napus) were investigated in a factorial field experiment at Hohenschulen Experimental Station near Kiel, NW Germany. The crop rotation was oilseed rape–winter wheat–winter barley, and soil tillage (conservation tillage without ploughing, conventional tillage), application of pig slurry (none, autumn, spring, autumn+spring) and mineral N fertilization (0 to 200 kg N ha−1) were all varied. Each year, the treatments were applied to all three crops of the rotation and were located on the same plots.Between the years, average seed yield ranged from 3·04 to 3·78 t ha−1, while the corresponding N uptake by the seed varied from 107 to 131 kg N ha−1. Slurry application in spring increased the seed yield and N uptake by the seed in all years, whereas the effect of autumn slurry alone or in combination with spring slurry was negligible. Mineral N fertilizer increased seed yield and N uptake by the seeds except in 1991/92, when N amounts exceeded 160 kg N ha−1. No significant slurry×mineral N interaction occurred. Apparent NUE of mineral N was larger than that of slurry N, but decreased with increasing mineral fertilizer N rates. Only 5% of the autumn slurry N was apparently utilized by the seeds, compared with 24% of the spring slurry N.Despite its ability to take up substantial quantities of N before the winter, oilseed rape utilized very little autumn slurry N for seed production. To minimize environmental impacts, slurry should be applied in the spring, when plants are more able to use N for yield formation, even if NUE of slurry N is lower than that of mineral N. However, since NUE changes with the amount of applied N, it is difficult to find the best combination of slurry and mineral N fertilization to avoid negative environmental effects.


2021 ◽  
Vol 11 ◽  
Author(s):  
Diana Heuermann ◽  
Heike Hahn ◽  
Nicolaus von Wirén

In agricultural plant production, nitrate, ammonium, and urea are the major fertilized nitrogen forms, which differ in root uptake and downstream signaling processes in plants. Nitrate is known to stimulate cytokinin synthesis in roots, while for urea no hormonal effect has been described yet. Elevated cytokinin levels can delay plant senescence favoring prolonged nitrogen uptake. As the cultivation of winter oilseed rape provokes high nitrogen-balance surpluses, we tested the hypotheses whether nitrogen use efficiency increases under ammonium nitrate- relative to urea-based nutrition and whether this is subject to genotypic variation. In a 2-year field study, 15 oilseed rape lines were fertilized either with ammonium nitrate or with urease inhibitor-stabilized urea and analyzed for seed yield and nitrogen-related yield parameters. Despite a significant environmental impact on the performance of the individual lines, which did not allow revealing consistent impact of the genotype, ammonium nitrate-based nutrition tended to increase seed yield in average over all lines. To resolve whether the fertilizer N forms act on grain yield via phytohormones, we collected xylem exudates at three developmental stages and determined the translocation rates of cytokinins and N forms. Relative to urea, ammonium nitrate-based nutrition enhanced the translocation of nitrate or total nitrogen together with cytokinins, whereas in the urea treatment translocation rates were lower as long as urea remained stable in the soil solution. At later developmental stages, i.e., when urea became hydrolyzed, nitrogen and cytokinin translocation increased. In consequence, urea tended to increase nitrogen partitioning in the shoot toward generative organs. However, differences in overall nitrogen accumulation in shoots were not present at the end of the vegetation period, and neither nitrogen uptake nor utilization efficiency was consistently different between the two applied nitrogen forms.


1996 ◽  
Vol 126 (1) ◽  
pp. 53-62 ◽  
Author(s):  
S. P. McGrath ◽  
F. J. Zhao

SUMMARYField experiments were conducted to test the seed yield responses of winter oilseed rape (Brassica napus L., cvs Libravo or Falcon) to the addition of different rates of S fertilizer, at three N application rates, on a sandy loam at Woburn, Bedfordshire, in 1990/91, 1991/92 and 1993/94. Large increases in seed yields, ranging from 0·7 to 1·6 t/ha, or 42–267% on a relative scale, were obtained in response to the application of 40 kg S/ha with 180 and 230 kg N/ha treatments. The effects of S were highly significant in 1991/92 (P < 0·01) and 1993/94 (P < 0·001) and close to significant (P = 0·053) in 1990/91. The yield benefits were obtained mainly from the application of the first 10 kg S/ha and further yield increases were unlikely above 40 kg S/ha. Increasing N application from 180 to 230 kg/ha decreased seed yield in 1990/91 and 1993/94, when no S was applied. In contrast, seed yield was not increased by S at zero or low (50 or 100 kg/ha) N rates. The interactions between N and S on seed yield were significant (P < 0·05) in 1990/91 but not in the other two seasons. Application of S also increased seed oil content in 1993/94, when the degree of S deficiency was particularly severe. With an application of 230 kg N/ha, the crops took up 5–22 kg S/ha at maturity when no S was applied and 26–51 kg S/ha when 40 kg S/ha was applied. The utilization efficiency of the fertilizer S ranged from 50 to 73% in the three seasons. Although the concentrations of total N in plants were largely unaffected by S treatments, large amounts of NO3-N accumulated in the leaves of S-deficient plants in 1993/94. This indicates that N metabolism was disrupted by S deficiency. The concentrations of S and the N: S ratios in different tissues and the whole plant changed considerably with time. The concentration of S in leaves at early flowering was found to be the best index in predicting S deficiency in terms of seed yield, and a critical value of 3·8 mg/g was obtained. In comparison, the N: S ratio in leaves at early flowering was a much poorer predictor of S deficiency.


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