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.

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.

scholarly journals A comparative study of genomic adaptations to low nitrogen availability in Genlisea aurea

2021 ◽  
Author(s):  
Thibaut Goldsborough
Keyword(s):  
Comparative Study ◽  
Nitrogen Availability ◽  
Trifolium Pratense ◽  
Nitrogen Starvation ◽  
Model Organism ◽  
Carnivorous Plant ◽  
High Nitrogen Content ◽  
High Nitrogen ◽  
Nitrogen Levels ◽  
Low Nitrogen

AbstractGenlisea aurea is a carnivorous plant that grows on nitrogen-poor waterlogged sandstone plateaus and is thought to have evolved carnivory as an adaptation to very low nitrogen levels in its habitat. The carnivorous plant is also unusual for having one of the smallest genomes among flowering plants. Genomic DNA is known to have a high nitrogen content and yet, to the author’s knowledge, no published study has linked nitrogen starvation of G. aurea with genome size reduction. This comparative study of the carnivorous plant G. aurea, the model organism Arabidopsis thaliana (Brassicaceae) and the nitrogen fixing Trifolium pratense (Fabaceae) attempts to investigate whether the genome, transcriptome and proteome of G. aurea showed evidence of adaptations to low nitrogen availability. It was found that although G. aurea’s genome, CDS and non-coding DNA were much lower in nitrogen than the genome of T. pratense and A. thaliana this was solely due to the length of the genome, CDS and non-coding sequences rather than the composition of these sequences.

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 An Integrated Analysis of the Rice Transcriptome and Metabolome Reveals Root Growth Regulation Mechanisms in Response to Nitrogen Availability

2019 ◽  
Vol 20 (23) ◽  
pp. 5893 ◽  
Author(s):  
Wei Xin ◽  
Lina Zhang ◽  
Wenzhong Zhang ◽  
Jiping Gao ◽  
Jun Yi ◽  
...  
Keyword(s):  
Root Growth ◽  
Differentially Expressed Genes ◽  
Nitrogen Availability ◽  
Rice Root ◽  
Integrated Analysis ◽  
High Nitrogen ◽  
Rice Roots ◽  
Regulation Mechanisms ◽  
Low Nitrogen ◽  
Nitrogen Conditions

Nitrogen is an essential nutrient for plant growth and basic metabolic processes. Root systems play an important role in the ability of plants to obtain nutrients from the soil, and are closely related to the growth and development of above-ground plants. Root morphology analysis showed that root growth was induced under low-nitrogen conditions and inhibited under high-nitrogen conditions. To better understand the molecular mechanisms and metabolic basis underlying the rice root response to nitrogen availability, an integrated analysis of the rice root transcriptome and metabolome under three environmental conditions (low-, control, and high-nitrogen conditions) was conducted. A total of 262 and 262 differentially level metabolites were identified under low- and high-nitrogen conditions, respectively. A total of 696 and 808 differentially expressed genes were identified under low- and high-nitrogen conditions, respectively. For both the differentially expressed genes and metabolites, KEGG pathway analysis indicated that amino acid metabolism, carbon and nitrogen metabolism, phenylpropanoid metabolism, and phytohormones’ signal transduction were significantly affected by nitrogen availability. Additionally, variable levels of 65 transcription factors (TFs) were identified in rice leaves exposed to high and low nitrogen, covering 22 TF families. These results also indicate that there is a significant difference in the transcriptional regulation mechanisms of rice roots between low and high nitrogen. In summary, our study provides new information for a further understanding of the response of rice roots to low-nitrogen and high-nitrogen conditions.

scholarly journals The Role of Gibberellins in Regulation of Nitrogen Uptake and Physiological Traits in Maize Responding to Nitrogen Availability

2020 ◽  
Vol 21 (5) ◽  
pp. 1824
Author(s):  
Yubin Wang ◽  
Qingqing Yao ◽  
Yushi Zhang ◽  
Yuexia Zhang ◽  
Jiapeng Xing ◽  
...  
Keyword(s):  
Nitrogen Availability ◽  
Physiological Responses ◽  
N Uptake ◽  
Nitrogen Supply ◽  
Rna Seq ◽  
Uptake Capacity ◽  
Use Efficiency ◽  
Low Nitrogen ◽  
N Use

Modified gibberellin (GA) signaling leads to semi-dwarfism with low nitrogen (N) use efficiency (NUE) in crops. An understanding of GA-mediated N uptake is essential for the development of crops with improved NUE. The function of GA in modulating N uptake capacity and nitrate (NO3−) transporters (NRTs) was analyzed in the GA synthesis-deficient mutant zmga3ox grown under low (LN) and sufficient (SN) N conditions. LN significantly suppressed the production of GA1, GA3, and GA4, and the zmga3ox plants showed more sensitivity in shoots as well as LN stress. Moreover, the higher anthocyanin accumulation and the decrease of chlorophyll content were also recorded. The net NO3− fluxes and 15N content were decreased in zmga3ox plants under both LN and SN conditions. Exogenous GA3 could restore the NO3− uptake in zmga3ox plants, but uniconazole repressed NO3− uptake. Moreover, the transcript levels of ZmNRT2.1/2.2 were downregulated in zmga3ox plants, while the GA3 application enhanced the expression level. Furthermore, the RNA-seq analyses identified several transcription factors that are involved in the GA-mediated transcriptional operation of NRTs related genes. These findings revealed that GAs influenced N uptake involved in the transcriptional regulation of NRTs and physiological responses in maize responding to nitrogen supply.

The competitive and yielding ability of some sub-tropical pasture species sown alone and in mixtures under intermittent grazing at Samford, south-eastern Queensland

1969 ◽  
Vol 9 (37) ◽  
pp. 181 ◽  
Author(s):  
RJ Jones ◽  
Davies J Griffiths ◽  
RB Waite
Keyword(s):  
White Clover ◽  
Competitive Ability ◽  
Grazing Management ◽  
Tropical Pasture ◽  
Weed Species ◽  
Rhodes Grass ◽  
Nitrogen Levels ◽  
Tropical Legumes ◽  
High Yields ◽  
Low Nitrogen

Eleven introduced tropical grasses were compared in single grass swards and nine of these were compared in mixtures containing two or three grasses. The pastures received 300 lb nitrogen an acre a year as urea and were grazed five times a year. A basal legume mixture of tropical legumes and white clover sown with the grasses failed to persist. There were large differences between the grasses in competitive ability and this varied with time. Samford Rhodes grass, Nandi setaria, and Pangola were the most aggressive, and the Paspalum species-P. plicatulum P. dilatum and P. commersonii the least aggressive. Hyparrhenia hirta, which had done well at low nitrogen levels, failed to compete with weed grasses at the higher nitrogen level used in this study. Rhyncheytrum repens and commercial Rhodes grass were the dominant weed grasses in the establishment year. These rapidly decreased with time, and Digitaria didacola-blue couch, became the dominant weed species. Plots containing Nandi setaria, Samford Rhodes grass, or Pangola, gave the highest yields, and plots containing P. dilatatum the lowest. There was no yield advantage in combining grasses in mixtures-the mixture giving similar or lower yields than the best grass in the mixture grown alone. Under a period of farm grazing the three Rhodes grasses used declined sharply and the proportion of blue couch increased. The high yields from plots dominated by blue couch indicate that, agronomically, this has been a neglected naturalized species. Only Nandi setaria and Pangola were able to compete effectively with blue couch under the 'farm grazing' management imposed.

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.

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.

Low-temperature induced floret sterility in the rice cultivars Calrose and Inga as influenced by nitrogen supply

1984 ◽  
Vol 24 (125) ◽  
pp. 255 ◽  
Author(s):  
DP Heenan
Keyword(s):  
Low Temperature ◽  
Pollen Development ◽  
Nitrogen Supply ◽  
Nitrogen Level ◽  
Rice Cultivars ◽  
High Nitrogen ◽  
Nitrogen Levels ◽  
High Nitrogen Level ◽  
Temperature Controlled

An experiment in temperature-controlled glasshouse chambers at Yanco Agricultural Institute examined floret sterility in lnga and Calrose rice induced by low temperature and high nitrogen level. Low temperature (12�C) ,for 4 d during microsporogenesis and anthesis produced considerable sterility in both cultivars; lnga was more sensitive than Calrose. Sensitivity was greatest when florets from the mid-section of the panicle were passing through the early microspore phase of pollen development. At both stages, the amount of low-temperature induced sterility was increased by high nitrogen supply. In the absence of low temperature, high nitrogen levels induced sterility in lnga only.

Influence of Light Regime and Leaf Nitrogen Concentration on 77k Fluorescence in Leaves of Four Tropical Grasses: No Evidence for Photoinhibition

1988 ◽  
Vol 15 (5) ◽  
pp. 669 ◽  
Author(s):  
MM Ludlow ◽  
SP Samarakoon ◽  
JR Wilson
Keyword(s):  
Nitrogen Content ◽  
Nitrogen Availability ◽  
Nitrogen Concentration ◽  
Chlorophyll Concentration ◽  
Leaf Nitrogen ◽  
Nitrogen Supply ◽  
Poor Growth ◽  
Full Sunlight ◽  
Nitrogen Treatments ◽  
Low Nitrogen

This work was undertaken to determine if the stimulation of growth associated with shading of some tropical C4 grasses growing on soils with low to moderate nitrogen availability is partly due to overcoming photoinhibition (i. e. damage caused by excessive light). Four grasses (green panic, carpet grass, buffalo grass and kikuyu) were grown in full sunlight and at 37% of full sunlight, and given a low or high nitrogen supply. Despite differences of up to twofold in leaf nitrogen and chlorophyll concentration between high and low nitrogen treatments in all four grasses, photoinhibition measured by reduction in chlorophyll fluorescence was less than 3% in leaves of low nitrogen content that developed in full sunlight. Therefore, photoinhibition is not a contributor to the poor growth of nitrogen-limited grasses in full sunlight. A second objective was to determine if low nitrogen content predisposed shade-grown leaves to photoinhibition when they were subsequently exposed to full sunlight. Green panic plants that had been given either high or low nitrogen supply and grown in 37% of full sunlight were transferred to full sunlight and the extent of photoinhibition was followed over 8 days. The amount of photoinhibition that occurred was small (<6%) compared with plants grown at either nitrogen level in full sunlight. Therefore, shade and low nitrogen content separately or in combination did not cause any appreciable photoinhibition in green panic.

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