Red clover varieties show nitrogen fixing advantage during the early stages of seedling development

2018 ◽  
Vol 98 (3) ◽  
pp. 517-526 ◽  
Author(s):  
M.S. Thilakarathna ◽  
Y.A. Papadopoulos ◽  
M. Grimmett ◽  
S.A.E. Fillmore ◽  
M. Crouse ◽  
...  
Keyword(s):  
Plant Growth ◽  
Root Exudate ◽  
Red Clover ◽  
Genotypic Differences ◽  
Inorganic N ◽  
N Content ◽  
Factors Affecting ◽  
Early Stages ◽  
N Concentration ◽  
N Release

Plant and environmental factors affect root nitrogen (N) exudation dynamics in legumes. To better understand the genotypic variability and plant factors affecting root N release nodulation, plant growth, tissue N content, and root N exudation, six (three diploid and three tetraploid) red clover (Trifolium pratense L.) varieties were evaluated under controlled environmental conditions during the first 8 wk of plant growth after rhizobia inoculation. Genotypic differences were found for nodulation, plant dry weight (DW), leaf area, root attributes (root length, surface area, volume, and diameter), shoot and root N concentration, and N content. Genotypic differences were also found for root exudate N content in terms of NO3−-N, NH4+-N, and dissolved organic N (DON). In general, root exudate inorganic N content was greater in tetraploid varieties than in the diploids throughout the growth period. Root exudate DON content was greater than the inorganic N content. The NO3−-N content in root exudate was positively correlated with root growth attributes and root N concentration, whereas NH4+-N content was positively correlated with nodule number. Root exudate DON was positively correlated with shoot N concentration and average nodule DW. These results highlight the existence of genotypic differences among red clover varieties for plant morphological factors affecting root N release during the early stages of plant development.

Soil inorganic nitrogen content in commercial potato fields in New Brunswick

2003 ◽  
Vol 83 (4) ◽  
pp. 425-429 ◽  
Author(s):  
B. J. Zebarth ◽  
Y. Leclerc ◽  
G. Moreau ◽  
R. Gareau ◽  
P. H. Milburn
Keyword(s):  
Root Zone ◽  
Inorganic Nitrogen ◽  
Solanum Tuberosum L ◽  
Red Clover ◽  
Application Rate ◽  
Inorganic N ◽  
N Content ◽  
Growing Seasons ◽  
Commercial Potato ◽  
Soil Inorganic

Information on inorganic N content in commercial potato fields in Atlantic Canada is limited. Soil inorganic N measurements were collected from 228 commercial potato fields from 1999 to 2001. Soil NO3 content to 30 cm depth at planting ranged from 2 to 124 kg N ha-1, and was generally higher for preceding potato, red clover, or hay crops compared to preceding cereal or other crops. Soil NH4 content to 30 cm depth measured at planting ranged from 3 to 64 kg N ha-1, indicating that both soil NO3 and NH4 need to be measured to assess plant-available soil N content in spring. Soil NO3 content to 30-cm depth at tuber harvest ranged from 3 to 250 kg N ha-1, generally increased with increasing fertilizer N application rate, and differed among different potato cultivars. Soil NO3 content measured to 30-cm depth in spring ranged from 3 to 100% of soil NO3 at harvest in the preceding fall, indicating that highly variable losses of soil NO3 from the root zone occur between growing seasons. Key words: Nitrate, ammonium, Solanum tuberosum L.

Nitrogen release from shoots and roots of crimson clover, hairy vetch, and red clover

2020 ◽  
Vol 100 (3) ◽  
pp. 179-188
Author(s):  
X.M. Yang ◽  
C.F. Drury ◽  
W.D. Reynolds ◽  
L.A. Phillips
Keyword(s):  
Cover Crops ◽  
Half Life ◽  
Red Clover ◽  
Organic N ◽  
Hairy Vetch ◽  
Inorganic N ◽  
Total N ◽  
Crimson Clover ◽  
N Release ◽  
Legume Cover Crops

Nitrogen (N) release from legume cover crops is a key N source for subsequent crops in rotation. In this study, chopped fresh shoots or roots (<5 mm) of crimson clover (CC), hairy vetch (HV), and red clover (RC) were incorporated into a 50:50 mixture of air-dried sandy loam soil (<2 mm) and washed builders sand at a rate of 300 mg N kg−1. The mixtures were packed in leaching tubes (four replicates), leached with 100 mL of 5 mmol L−1 CaCl2, and then incubated for 10 wk (22 °C, 0.33 bar matric potential) with weekly leaching. Total N and inorganic N (NH4+ plus NO3−) in leachate were quantified and organic N was determined as the difference between total N and inorganic N. More N was released from shoots (63.4%–70.0% of initial N) than from roots (27.3%–50.7% of initial N). Mineralized organic N and inorganic N followed the first order, single N-pool mineralization model [Nt = N0(1 – e−kt); R2 = 0.94−0.99]. Potentially mineralizable N (N0, as % of initial N) was similar for shoots (CC = 75.1%, HV = 74.2%, and RC = 71.3%), but varied for roots (CC = 36.2%, HV = 52.6%, and RC = 53.0%). The N0 pool in shoots had a half-life (t1/2 = ln 2/k) of 11.0, 9.8, and 15.1 d for CC, HV, and RC, respectively; and a half-life in roots of 23.9, 8.5, and 25.7 d, respectively. Hence, HV released its stored N in both roots and shoots faster than CC and RC. The results in this study would help farmers optimize their choice in legume cover crops and termination times to better synchronize N release with crop uptake.

Further Studies upon Chemical Factors Affecting the Breeding of Anopheles in Trinidad

1934 ◽  
Vol 25 (4) ◽  
pp. 491-494 ◽  
Author(s):  
P. A. Buxton
Keyword(s):  
Analytical Study ◽  
Chemical Constituents ◽  
Physical Factors ◽  
Factors Affecting ◽  
Early Stages ◽  
Freshwater Biology ◽  
Chemical Technique ◽  
Chemical Factors ◽  
Physical And Chemical

During the last decade, entomologists have made progress in understanding the environment in which certain insects live; in particular, we begin to understand the effect of certain physical and chemical factors, which make up a part of the environment. With this gain in knowledge, it is sometimes possible to forecast outbreaks of insects and of diseases conveyed by them, and one can sometimes say that a particular alteration of the environment will result in loss or gain. But so far as mosquitos are concerned, one must admit that though much work has been devoted to the analytical study of the water in which the early stages are passed, the results are disappointing. A consideration of the published work suggests several reasons for this. Investigation into the ecology of the mosquito has had a vogue, and much of it has been done by workers who were isolated and whose knowledge of chemical technique and freshwater biology was limited. Apart from that, the inherent difficulties are great, for the worker must hunt for the limiting chemical and physical factors among a host of others which are doubtless unimportant, and there are few clues to indicate which of the chemical constituents of the water affects the mosquito. The data are therefore voluminous and it is difficult to reduce them to order and present them so that they can be readily understood.

scholarly journals Plant and soil nitrogen in oligotrophic boreal forest habitats with varying moss depths: does exclusion of large grazers matter?

Oecologia ◽  
2021 ◽  
Author(s):  
Maria Väisänen ◽  
Maria Tuomi ◽  
Hannah Bailey ◽  
Jeffrey M. Welker
Keyword(s):  
Boreal Forest ◽  
Vascular Plant ◽  
Soil N ◽  
Inorganic N ◽  
N Dynamics ◽  
N Content ◽  
Feather Moss ◽  
Foliar N ◽  
Plant Soil ◽  
Plant Soil Interactions

AbstractThe boreal forest consists of drier sunlit and moister-shaded habitats with varying moss abundance. Mosses control vascular plant–soil interactions, yet they all can also be altered by grazers. We determined how 2 decades of reindeer (Rangifer tarandus) exclusion affect feather moss (Pleurozium schreberi) depth, and the accompanying soil N dynamics (total and dissolvable inorganic N, δ15N), plant foliar N, and stable isotopes (δ15N, δ13C) in two contrasting habitats of an oligotrophic Scots pine forest. The study species were pine seedling (Pinus sylvestris L.), bilberry (Vaccinium myrtillus L.), lingonberry (V. vitis-idaea L.), and feather moss. Moss carpet was deeper in shaded than sunlit habitats and increased with grazer exclusion. Humus N content increased in the shade as did humus δ15N, which also increased due to exclusion in the sunlit habitats. Exclusion increased inorganic N concentration in the mineral soil. These soil responses were correlated with moss depth. Foliar chemistry varied due to habitat depending on species identity. Pine seedlings showed higher foliar N content and lower foliar δ15N in the shaded than in the sunlit habitats, while bilberry had both higher foliar N and δ15N in the shade. Thus, foliar δ15N values of co-existing species diverged in the shade indicating enhanced N partitioning. We conclude that despite strong grazing-induced shifts in mosses and subtler shifts in soil N, the N dynamics of vascular vegetation remain unchanged. These indicate that plant–soil interactions are resistant to shifts in grazing intensity, a pattern that appears to be common across boreal oligotrophic forests.

Current Scenario of Root Exudate–Mediated Plant-Microbe Interaction and Promotion of Plant Growth

2017 ◽  
pp. 349-369 ◽  
Author(s):  
Kanchan Vishwakarma ◽  
Shivesh Sharma ◽  
Vivek Kumar ◽  
Neha Upadhyay ◽  
Nitin Kumar ◽  
...  
Keyword(s):  
Plant Growth ◽  
Root Exudate ◽  
Plant Microbe Interaction ◽  
Current Scenario

Functional analysis of the genotypic differences in response to calcareous-induced iron deficiency in pea plants (Pisum sativum L.)

2021 ◽  
Author(s):  
Sameh Barhoumi ◽  
Hasna Ellouzi ◽  
Abdelmajid KROUMA
Keyword(s):  
Oxidative Stress ◽  
Iron Deficiency ◽  
Plant Growth ◽  
Calcareous Soil ◽  
Growth And Yield ◽  
Yield Reduction ◽  
Genotypic Differences ◽  
Sod Activity ◽  
Screening Programs ◽  
Use Efficiency

Abstract Background Lime-induced iron deficiency in Pea plants is a major nutritional disorder causing severe plant growth and yield reduction in calcareous soils of Tunisia. Other the chemical fertilization for iron chlorosis correction, the exploration of the genotypic differences in response to this constraint remains the most efficient approach due to its coast, environmental benefits, and sustainability. This approach allows as to screen tolerant genotypes and identify useful traits of tolerance. Results calcareous-induced iron deficiency reduced SPAD index, plant growth, net photosynthesis, and tissues Fe concentration against a significant stimulation of the oxidative stress indicators, H2O2 and Malondialdehyde (MDA). In the same time, we have reported significant induction of SOD activity in shoots and CAT activity in roots of the genotype Alexandra (ne clear behavior observed in the other genotypes). Fe use efficiency increased on calcareous soil and clearly discriminates the studied genotypes. Conclusion Genotypic differences were observed, and Alex was found to be the most tolerant. This genotype protect its tissues against oxidative stress by stimulating SOD activity in shoots and CAT içn roots, and expressed significant efficiency of Fe uptake and use on calcareous soil. The Fe use efficiency for photosynthesis and for SOD and CAT activities clearly discriminates the studied genotypes and can be used as a useful trait for further screening programs.

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