The absorption and distribution of nitrogen after floret initiation in wheat

1969 ◽  
Vol 20 (5) ◽  
pp. 799 ◽  
Author(s):  
HM Rawson ◽  
CM Donald
Keyword(s):  
No Value ◽  
Wheat Plant ◽  
Nitrogen Supply ◽  
Main Stem ◽  
Fertile Plant ◽  
High Nitrogen ◽  
Plant Parts ◽  
Labelled Nitrogen ◽  
To Receive ◽  
Low Nitrogen

The pattern of absorption and distribution of nitrogen after floret initiation in wheat was examined with the aid of labelled nitrogen with a view to determining the importance of sterile tillers as a source of nitrogen for the fertile parts of the plant. Tertiary tillers were found to be of no importance as direct importers of nitrogen from the growth medium; absorption by these tillers was almost entirely via the roots of the main stem and the primary tillers. In conditions of high nitrogen supply the tertiary tillers continued to receive nitrogen from the main stem and primary tillers, but the tertiary tillers of low nitrogen plants were starved of nitrogen and soon senesced. When the sterile, tertiary tillers died there was a remobilization of most of their nitrogen, apparently to the fertile parts (main stem, primary and some secondary tillers) of the plant, but a small quantity of nitrogen was also lost to the nutrient solution. It is concluded that although sterile, tertiary tillers act as a temporary nutrient reservoir for the fertile plant parts, they are in fact of little or no value and may well be regarded as a useless vestige of perenniality in the wheat plant.

Competition between skeleton weed (Chondrila juncea L) and cereals in relation to nitrogen supply

1958 ◽  
Vol 9 (1) ◽  
pp. 1 ◽  
Author(s):  
LF Myers ◽  
J Lipsett
Keyword(s):  
Crop Yields ◽  
Nitrogen Supply ◽  
Weed Competition ◽  
Nitrogen Application ◽  
High Nitrogen ◽  
Nitrogen Levels ◽  
Grain Nitrogen ◽  
Low Nitrogen ◽  
Yield Of Oats ◽  
Plant Growth Regulating Substances

The effect of skeleton weed competition on the yield of wheat and oats was investigated in seasons when rainfall was plentiful. Nitrogen was found to be the major factor limiting crop yields. In soils with comparable nitrogen-supplying powers, skeleton weed density governed the crop's response to applied nitrogen. Competition between skeleton weed and crop was severe at low nitrogen levels, but minor at the high nitrogen levels achieved either by nitrogen application, or when the crop followed a legume-rich pasture. Competition had its effect early in the crop's growth. Temporary removal of competition, by spraying with plant growth regulating substances (JICPA) at different times, was used to determine when competition was critical, and measure its effects. Skeleton weed reduced nitrogen supply early in the crop's growth, and so depressed yield. An application of 1 lb MCPA per acre in the fallow 54 days before sowing, or 10 days after crop emergence, increased the yield of oats from 710 to 1350 lb grain per acre: a response equal to that from 32 lb nitrogen per acre applied at planting in the same experiment. In each case, the response to spraying at the different times was analogous to the effect of a nitrogen application at these times. Early spraying gave responses in yield; later spraying gave responses in grain nitrogen. The results provide a new estimate of the reduction in crop yield due to skeleton weed.

Effect of nitrogen fertilization on the growth of Sporobolomyces roseus on wheat leaves

1982 ◽  
Vol 60 (12) ◽  
pp. 2741-2744 ◽  
Author(s):  
R. Frossard ◽  
N. J. Fokkema
Keyword(s):  
Spring Wheat ◽  
Nitrogen Fertilization ◽  
Nitrogen Supply ◽  
Nitrogen Compounds ◽  
Controlled Environment ◽  
High Nitrogen ◽  
Flag Leaves ◽  
Sporobolomyces Roseus ◽  
Wheat Leaves ◽  
Low Nitrogen

Green flag leaves of spring wheat grown with low or high nitrogen supply in the form of Ca(NO3)2 were inoculated with Sporobolomyces roseus. Growth of the yeast in a controlled environment was followed for several days by culturing techniques. No consistent differences were found between the development of S. roseus on leaves from low or high nitrogen treated plants, suggesting that leaf exudates from low nitrogen treated plants still contain enough nitrogen compounds to support growth of S. roseus. Nitrogen fertilization obviously seems not to be an appropriate means to manipulate the phyllosphere mycoflora.

Shoot biomass in wheat is the driver for nitrogen uptake under low nitrogen supply, but not under high nitrogen supply

2014 ◽  
Vol 165 ◽  
pp. 92-98 ◽  
Author(s):  
Yoshiaki Kamiji ◽  
Jiayin Pang ◽  
Stephen P. Milroy ◽  
Jairo A. Palta
Keyword(s):  
Nitrogen Uptake ◽  
Nitrogen Supply ◽  
Shoot Biomass ◽  
High Nitrogen ◽  
Low Nitrogen

Effects of endophyte infection on the competitive ability of Achnatherum sibiricum depend on endophyte species and nitrogen availability

2019 ◽  
Vol 12 (5) ◽  
pp. 815-824
Author(s):  
Yong Zhou ◽  
Xia Li ◽  
Hui Liu ◽  
Yubao Gao ◽  
Wade J Mace ◽  
...  
Keyword(s):  
Dominant Species ◽  
Competitive Ability ◽  
Nitrogen Availability ◽  
Inhibitory Effect ◽  
Nitrogen Supply ◽  
Tiller Number ◽  
High Nitrogen ◽  
Nitrogen Levels ◽  
Endophyte Infection ◽  
Low Nitrogen

Abstract Aims The leaves of almost all terrestrial plant species are colonized by endophytic fungi. Compared to agronomic grasses, which usually harbor few endophytes, native grasses generally possess greater endophyte species diversity. Existing studies examining endophyte effects on natural grasses under competition normally considered the infection status (infected or uninfected), and rarely considered endophyte species. Methods We examined the effects of endophyte infection and of endophyte species on the interspecific competitive ability of a subdominant species, Achnatherum sibiricum, at two nitrogen levels (high nitrogen and low nitrogen). Achnatherum sibiricum plants infected by two different species of endophyte (Epichloë sibirica and E. gansuensis) and uninfected plants were grown in monoculture and binary mixtures with a dominant species, Stipa grandis (six individuals per species for monocultures and three + three individuals of each species in mixtures). Shoot and root biomass, tiller number and total phenolic concentration were measured after 3 months. Moreover, the aggressivity index was calculated to compare the competitive ability of A. sibiricum relative to S. grandis. Important Findings Both E. gansuensis (Eg)- and E. sibirica (Es)-infected A. sibiricum plants showed a greater competitive ability than the uninfected plants under high nitrogen supply, while the opposite result occurred under low nitrogen supply. At high nitrogen levels, Eg plants had a higher tiller number and a greater shoot biomass inhibitory effect on S. grandis than Es plants had when growing in mixture, while Es plants showed better root growth performance than Eg and uninfected plants under mixture conditions at all nitrogen levels. A higher concentration of phenolic compounds in Eg plants than in Es plants might contribute to the higher inhibitory effect of Eg plants on competing plants. Our study indicates that the interaction between endophyte infection and nitrogen availability can alter the competitive ability of the host plant A. sibiricum but that these two endophyte species work in different ways, which may influence the coexistence of A. sibiricum with the dominant species.

The comparative phosphate requirements of four annual pastures and two crops

1976 ◽  
Vol 27 (4) ◽  
pp. 479 ◽  
Author(s):  
PG Ozanne ◽  
KMW Howes ◽  
A Petch
Keyword(s):  
Unit Area ◽  
Maximum Yield ◽  
Subterranean Clover ◽  
Single Species ◽  
Nitrogen Supply ◽  
High Nitrogen ◽  
Direct Response ◽  
Phosphorus Requirement ◽  
Wimmera Ryegrass ◽  
Low Nitrogen

The levels of broadcast phosphate needed for 90% of maximum production by subterranean clover, Wimmera ryegrass at two levels of nitrogen, wheat and lupins are compared in a field experiment. Two seeding rates, one five times the other, were used to vary the stand densities and yields per unit area of the swards. A total of 180 kg nitrogen/ha was supplied to the wheat and high nitrogen grass plots; the low nitrogen grass plots received 30 kg/ha. Although both the high seeding rates and the high nitrogen applications gave up to double the yield per unit area, they did not significantly change the level of phosphate required for 90% of maximum yield by a given species or mixture. Grown as single species, lupins had the highest phosphorus requirement (202 kg/ha); wheat (118 kg/ha) and clover (107 kg/ha) had similar requirements; while grass with either a low nitrogen supply (58 kg/ha) or a high nitrogen supply (56 kg/ha) had the lowest requirement when measured during flowering. When clover and ryegrass were grown as a mixed sward, the phosphorus requirement (84 kg/ha) was close to the average of those for the pure clover and grass. Both the grass and clover responded to approximately the same level of phosphate when grown as a mixture. The amount of nitrogen fixed by the clover, either as a pure sward or when mixed with grass, increased with increasing phosphate application. We think that the phosphate level required by the grass when grown with clover rather than as a pure sward was an expression of this increased nitrogen supply and not a direct response to phosphate. The levels of phosphate required to produce 90% of the maximum grain yield in the lupin and ear yield in the wheat were similar to the phosphate requirement for 90% of maximum vegetative yield.

scholarly journals Nitrogen Levels Regulate Sugar Metabolism and Transport in the Shoot Tips of Crabapple Plants

2021 ◽  
Vol 12 ◽  
Author(s):  
Lihua Zhang ◽  
Simin Sun ◽  
Yonghui Liang ◽  
Baiyun Li ◽  
Songya Ma ◽  
...  
Keyword(s):  
Sugar Metabolism ◽  
Net Photosynthesis ◽  
Sucrose Phosphate Synthase ◽  
Nitrogen Supply ◽  
Shoot Tips ◽  
High Nitrogen ◽  
Nitrogen Levels ◽  
Nitrogen Treatment ◽  
Low Nitrogen ◽  
Growing Shoot

To comprehensively understand the responses of carbohydrate metabolism and transport to different levels of nitrogen supply in growing shoot tips of crabapple (Malus hupehensis Rehd), enzyme activities and related genes involved in the sugar metabolism pathway were investigated. The nitrogen and chlorophyll content of plants increased with increasing nitrogen supply. High nitrogen application increased the net photosynthesis rate and the growth rate of shoot tips but decreased the synthesis capability of sucrose and sorbitol in mature leaves. However, the shoot tips of plants under high-nitrogen treatment had higher contents of sucrose and sorbitol than did those under low-nitrogen treatment, while the activity of sucrose phosphate synthase and aldose-6-phosphate was increased and the transporters MdSOT and MdSUT were up-regulated. Moreover, the activities of enzymes involved in sucrose and hexose metabolism (including sucrose synthase, fructokinase, and hexokinase) were enhanced in the shoot tips of plants under high-nitrogen conditions, and the expression levels of MdSUSY3 and MdHK1 were significantly up-regulated. These findings indicate that a high nitrogen supply increases the metabolic capacity of assimilatory substances in shoot tips, accelerates the efficiency of sugar utilization and eventually leads to a rapid increase in the growth of shoot tips. Our results highlight that high nitrogen increases the capacity of sugar unloading and metabolic utilization in growing shoot tissues.

scholarly journals Genome-wide association of rice response to blast fungus identifies loci for robust resistance under high nitrogen

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Mathias Frontini ◽  
Arnaud Boisnard ◽  
Julien Frouin ◽  
Malika Ouikene ◽  
Jean Benoit Morel ◽  
...  
Keyword(s):  
Nitrogen Fertilization ◽  
Rice Blast ◽  
Genome Wide Association ◽  
Japonica Rice ◽  
High Nitrogen ◽  
Initial Finding ◽  
Blast Fungus ◽  
Genome Wide ◽  
A Genome ◽  
Low Nitrogen

Abstract Background Nitrogen fertilization is known to increase disease susceptibility, a phenomenon called Nitrogen-Induced Susceptibility (NIS). In rice, this phenomenon has been observed in infections with the blast fungus Magnaporthe oryzae. A previous classical genetic study revealed a locus (NIS1) that enhances susceptibility to rice blast under high nitrogen fertilization. In order to further address the underlying genetics of plasticity in susceptibility to rice blast after fertilization, we analyzed NIS under greenhouse-controlled conditions in a panel of 139 temperate japonica rice strains. A genome-wide association analysis was conducted to identify loci potentially involved in NIS by comparing susceptibility loci identified under high and low nitrogen conditions, an approach allowing for the identification of loci validated across different nitrogen environments. We also used a novel NIS Index to identify loci potentially contributing to plasticity in susceptibility under different nitrogen fertilization regimes. Results A global NIS effect was observed in the population, with the density of lesions increasing by 8%, on average, under high nitrogen fertilization. Three new QTL, other than NIS1, were identified. A rare allele of the RRobN1 locus on chromosome 6 provides robust resistance in high and low nitrogen environments. A frequent allele of the NIS2 locus, on chromosome 5, exacerbates blast susceptibility under the high nitrogen condition. Finally, an allele of NIS3, on chromosome 10, buffers the increase of susceptibility arising from nitrogen fertilization but increases global levels of susceptibility. This allele is almost fixed in temperate japonicas, as a probable consequence of genetic hitchhiking with a locus involved in cold stress adaptation. Conclusions Our results extend to an entire rice subspecies the initial finding that nitrogen increases rice blast susceptibility. We demonstrate the usefulness of estimating plasticity for the identification of novel loci involved in the response of rice to the blast fungus under different nitrogen regimes.

scholarly journals Genotypic Variationin Dry Weight and Nitrogen Concentration of Wheat Plant Parts; Relations to Grain Yield and Grain Protein Concentration

2012 ◽  
Vol 4 (11) ◽  
Author(s):  
Ali Hafeez Malik ◽  
Allan Andersson ◽  
Ramune Kuktaite ◽  
Muhammad Yaqub Mujahid ◽  
Bismillah Khan ◽  
...  
Keyword(s):  
Grain Yield ◽  
Protein Concentration ◽  
Nitrogen Concentration ◽  
Wheat Plant ◽  
Dry Weight ◽  
Grain Protein ◽  
Grain Protein Concentration ◽  
Plant Parts

The influence of diet on the nitrogenous components passing to the duodenum and through the lower ileum of sheep

1966 ◽  
Vol 166 (1002) ◽  
pp. 63-79 ◽  
Keyword(s):  
Amino Acids ◽  
Glutamic Acid ◽  
Nitrogen Content ◽  
Aspartic Acid ◽  
Total Nitrogen ◽  
Amino Nitrogen ◽  
Terminal Part ◽  
High Nitrogen ◽  
Low Nitrogen ◽  
Lower Ileum

Analyses of the alimentary contents flowing to the duodenum of sheep during 24 h show that when the sheep are consuming a low-nitrogen diet more total nitrogen and amino nitrogen pass to the duodenum than are eaten daily in the food whereas when the sheep are eating high nitrogen diets, less total nitrogen and less amino nitrogen pass to the duodenum. The disparity between the total nitrogen and amino nitrogen content of the diets largely disappeared by the time the alimentary contents reached the terminal part of the ileum. From 64 to 68% of the nitrogen entering the duodenum and 54 to 64% of the nitrogen in the ileal contents was in the form of amino nitrogen. Proportionately more of the amino nitrogen was in solution in the ileal contents than in the duodenal contents. Losses of amino acids in the stomach when a high-nitrogen diet was consumed were especially large for glutamic acid, aspartic acid, proline, arginine and leucine. They were least for cystine and threonine. Gains of amino acids in the stomach when low nitrogen diets were consumed were all substantial except for proline, where a loss was found when hay and flaked maize were given. When these changes are considered as proportions of the quantities eaten then trends are similar for all acids. Changes in the molar proportions of the amino acids present in hydrolysates of the duodenal and ileal contents are discussed together with the significance of these changes in relation to the nutrition of the sheep.

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