scholarly journals The impact of a native hemiparasite on a major invasive shrub is affected by host size at time of infection

2020 ◽  
Vol 71 (12) ◽  
pp. 3725-3734
Author(s):  
Robert M Cirocco ◽  
José M Facelli ◽  
Jennifer R Watling
Keyword(s):  
Root Biomass ◽  
Isotope Composition ◽  
Nitrogen Concentration ◽  
Host Size ◽  
Quantum Yields ◽  
Total Biomass ◽  
Invasive Shrub ◽  
Ulex Europaeus ◽  
Nodule Biomass ◽  
The Impact

Abstract Many studies have investigated the effect of parasitic plants on their hosts; however, few have examined how parasite impact is affected by host size. In a glasshouse experiment, we investigated the impact of the Australian native hemiparasitic vine, Cassytha pubescens, on a major invasive shrub, Ulex europaeus, of different sizes. Infected plants had significantly lower total, shoot, and root biomass, but the parasite’s impact was more severe on small than on large hosts. When infected, small but not large hosts had significantly lower nodule biomass. Irrespective of size, infection significantly decreased the host shoot/root ratio, pre-dawn and midday quantum yields, maximum electron transport rates, and carbon isotope composition, and the host nodule biomass per gram of root biomass significantly increased in response to infection. Infection did not affect host foliar nitrogen concentration or midday shoot water potential. Parasite biomass was significantly lower on small relative to large hosts, but was similar when expressed on a per gram of host total biomass basis. Parasite stem nitrogen, phosphorus, and potassium concentrations were significantly greater when C. pubescens was growing on small than on large hosts. Our results clearly show that C. pubescens strongly decreases performance of this major invasive shrub, especially when hosts are small. This suggests that C. pubescens could be used most effectively as a native biocontrol when deployed on smaller hosts.

The impact of defoliation on nitrogen translocation patterns in the woody invasive plant, Buddleia davidii

2008 ◽  
Vol 35 (6) ◽  
pp. 462 ◽  
Author(s):  
Marc M. Thomas ◽  
Pete Millard ◽  
Michael S. Watt ◽  
Matthew H. Turnbull ◽  
Duane Peltzer ◽  
...  
Keyword(s):  
Invasive Plant ◽  
Control Measure ◽  
Total Biomass ◽  
Invasive Shrub ◽  
Growing Seasons ◽  
Invasive Spread ◽  
Buddleia Davidii ◽  
Induced Changes ◽  
The Impact ◽  
N Remobilisation

The influence of defoliation on nitrogen (N) re-translocation and the source for N remobilisation by the invasive shrub, Buddleia davidii Franch. (buddleia) was determined. Eighty plants were grown over two growing seasons, and half were repeatedly defoliated by removing 66% of their leaf area. During the second season, the N supply was labelled with 15N (10 atom% enrichment), to distinguish the use of stored N (unlabelled) from N taken up by roots (labelled) for growth. Defoliation significantly decreased root (39%) and total biomass (26%). Old leaves were the main source of N for remobilisation which was accelerated and increased (by 50% in the second season) in response to defoliation. In spring, root uptake of N increased by 57% in defoliated plants. Thus, defoliation induced changes in N remobilisation and uptake as compensatory growth increased the demand for N. Continued leaf removal decreased the pool of stored N and caused a significant decline in biomass production, especially in roots (39%) and flowers (31%). This has important implications for the efficacy of defoliation as a control measure, as smaller roots suggest a reduced capacity for uptake of nutrients from the soil and reduced flower production may assist in reducing the invasive spread of the species. These findings clearly show that, although the success of B. davidii is associated, in part, with efficient remobilisation of N from storage, this advantage can be overcome by continued defoliation.

The impact of temperature on the degree of structurization of water of different isotope composition

2017 ◽  
Vol 39 (4) ◽  
pp. 185-190
Author(s):  
V. V. Goncharuk ◽  
I. Yu. Romanyukina ◽  
M. D. Skil’skaya ◽  
A. I. Marynin ◽  
A. V. Syroeshkin ◽  
...  
Keyword(s):  
Isotope Composition ◽  
The Impact

Biomass allocation in tomato (Lycopersicon esculentum) plants grown under partial rootzone drying: enhancement of root growth

2004 ◽  
Vol 31 (10) ◽  
pp. 971 ◽  
Author(s):  
Darren M. Mingo ◽  
Julian C. Theobald ◽  
Mark A. Bacon ◽  
William J. Davies ◽  
Ian C. Dodd
Keyword(s):  
Lycopersicon Esculentum ◽  
Root System ◽  
Biomass Allocation ◽  
Root Biomass ◽  
Leaf Water ◽  
Total Biomass ◽  
Split Root ◽  
Split Root System ◽  
Partial Rootzone Drying ◽  
And Control

Tomato (Lycopersicon esculentum Mill.) plants were grown in either a glasshouse (GH) or a controlled environment cabinet (CEC) to assess the effects of partial rootzone drying (PRD) on biomass allocation. Control and PRD plants received the same amounts of water. In control plants, water was equally distributed between two compartments of a split-root system. In PRD plants, only one compartment was watered while the other was allowed to dry. At the end of each drying cycle, wet and dry compartments were alternated. In the GH, total biomass did not differ between PRD and control plants after four cycles of PRD, but PRD increased root biomass by 55% as resources were partitioned away from shoot organs. In the CEC, leaf water potential did not differ between treatments at the end of either of two cycles of PRD, but stomatal conductance of PRD plants was 20% less at the end of the first cycle than at the beginning. After two cycles of PRD in the CEC, biomass did not differ between PRD and control plants, but PRD increased root biomass by 19% over the control plants. The promotion of root biomass in PRD plants was associated with the alternation of wet and dry compartments, with increased root biomass occurring in the re-watered compartment after previous exposure to soil drying. Promotion of root biomass in field-grown PRD plants may allow the root system to access resources (water and nutrients) that would otherwise be unavailable to control plants. This may contribute to the ability of PRD plants to maintain similar leaf water potentials to conventionally irrigated plants, even when smaller irrigation volumes are supplied.

Epithermal Fluorite Deposits in Transbaikalia (Geochemical Features, Sources of Matter and Fluids, and Genesis)

2021 ◽  
Vol 62 (4) ◽  
pp. 415-426
Author(s):  
E.I. Lastochkin ◽  
G.S. Ripp ◽  
D.S. Tsydenova ◽  
V.F. Posokhov ◽  
A.E. Murzintseva
Keyword(s):  
Meteoric Water ◽  
Isotope Composition ◽  
Spatial Proximity ◽  
Thermal Waters ◽  
Sr Isotope ◽  
Light Isotope ◽  
Geochemical Parameters ◽  
Nd Systems ◽  
Deep Source ◽  
The Impact

Abstract —We consider the isotope-geochemical features of epithermal fluorite deposits in Transbaikalia, including the REE compositions, Sr isotope ratios, Sm–Nd systems, and isotope compositions of oxygen, carbon, hydrogen, and sulfur. The 87Sr/86Sr ratios in fluorites are within 0.706–0.708, and the εNd values are negative. Oxygen in quartz, the main mineral of the deposits, has a light isotope composition (δ18O = –3.4 to +2.6‰), and the calculated isotope composition of oxygen in the fluid in equilibrium with quartz (δ18O = –9 to –16‰) indicates the presence of meteoric water. The latter is confirmed by analysis of the isotope compositions of oxygen and hydrogen in gas–liquid inclusions in fluorites from three deposits. These isotope compositions are due to recycling caused by the impact of shallow basic plutons. The isotope composition of sulfur indicates its deep source. During ascent, sulfur became enriched in its light isotope (δ34S = –1.8 to –7.7‰). We assess the association of fluorite ores with basaltoids widespread in the study area. The isotope and geochemical parameters suggest their spatial proximity. Probably, the basaltoids were responsible for the recycling of meteoric water. It is shown that the epithermal fluorite deposits formed by the same mechanism as fissure–vein thermal waters in western Transbaikalia.

scholarly journals Modeling of photolysis rates over Europe: impact on chemical gaseous species and aerosols

2011 ◽  
Vol 11 (4) ◽  
pp. 1711-1727 ◽  
Author(s):  
E. Real ◽  
K. Sartelet
Keyword(s):  
Air Quality ◽  
Transport Model ◽  
Quantum Yields ◽  
Strong Impact ◽  
Peak Reduction ◽  
Gaseous Species ◽  
Clear Sky ◽  
Photolysis Rate ◽  
Photolysis Rates ◽  
The Impact

Abstract. This paper evaluates the impact of photolysis rate calculation on simulated European air composition and air quality. In particular, the impact of the cloud parametrisation and the impact of aerosols on photolysis rates are analysed. Photolysis rates are simulated using the Fast-JX photolysis scheme and gas and aerosol concentrations over Europe are simulated with the regional chemistry-transport model Polair3D of the Polyphemus platform. The photolysis scheme is first used to update the clear-sky tabulation of photolysis rates used in the previous Polair3D version. Important differences in photolysis rates are simulated, mainly due to updated cross-sections and quantum yields in the Fast-JX scheme. In the previous Polair3D version, clouds were taken into account by multiplying the clear-sky photolysis rates by a correction factor. In the new version, clouds are taken into account more accurately by simulating them directly in the photolysis scheme. Differences in photolysis rates inside clouds can be large but outside clouds, and especially at the ground, differences are small. To take into account the impact of aerosols on photolysis rates, Polair3D and Fast-JX are coupled. Photolysis rates are updated every hour. Large impact on photolysis rates is observed at the ground, decreasing with altitude. The aerosol specie that impact the most photolysis rates is dust especially in south Europe. Strong impact is also observed over anthropogenic emission regions (Paris, The Po and the Ruhr Valley) where mainly nitrate and sulphate reduce the incoming radiation. Differences in photolysis rates lead to changes in gas concentrations, with the largest impact simulated on OH and NO concentrations. At the ground, monthly mean concentrations of both species are reduced over Europe by around 10 to 14% and their tropospheric burden by around 10%. The decrease in OH leads to an increase of the life-time of several species such as VOC. NO2 concentrations are not strongly impacted and O3 concentrations are mostly reduced at the ground (−3%). O3 peaks are systematically decreased because of the NO2 photolysis rate coefficient decrease. Not only gas are impacted but also secondary aerosols, due to changes in gas precursors concentrations. However changes in aerosol species concentrations often compensate each other resulting in a low impact on PM10 and PM2.5 concentrations (lower than 2%). The changes in gas concentrations at the ground induced by the modification of photolysis rates (by aerosols and clouds) are compared to changes induced by 29 different model parametrisations in Roustan et al. (2010). Among the 31 model parametrisations, "including aerosols on photolysis rates calculation" has the strongest impact on OH concentrations and on O3 bias in July. In terms of air quality, ground concentrations (NO2, O3, PM10) are compared with measurements. Changes arising from cloud parametrisation are small. Simulation performances are often slightly better when including aerosol in photolysis rates calculation. The systematic O3 peak reduction leads to large differences in the exceedances of the European O3 standard as calculated by the model, in better agreement with measurements. The number of exceedances of the information and the alert threshold is divided by 2 when the aerosol impact on photochemistry is simulated. This shows the importance of taking into account aerosols impact on photolysis rates in air quality studies.

scholarly journals Early root development of Eucalyptus pellita F. Muell. seedlings from seed and stem cutting at nursery stage

2020 ◽  
Author(s):  
Affendy Hassan ◽  
Parveena Balachandran ◽  
Khairiyyah Razanah Khamis
Keyword(s):  
Root Development ◽  
Root Length ◽  
Root Biomass ◽  
Nitrogen Concentration ◽  
Stem Cutting ◽  
Shoot Biomass ◽  
Forest Plantation ◽  
Plant Materials ◽  
Eucalyptus Pellita ◽  
Root Intensity

Abstract BackgroundEucalyptus is among the important fast-growing species, and is typically managed on short rotation to sustain the production of timber, pulpwood, charcoal, and fire-wood. Macro-propagation using cutting for larger multiplying seedlings is cheaper and efficient instead of clonal seeds for uniform plant material seedling production. However, information on root growth of Eucalyptus pellita at early development from seed and stem cutting of E. pellita seedlings is still lacking. This is probably due to the difficulty in investigation belowground, and also due to methodological problems. With such information, it is useful for forest plantation company management in enhancing the understanding on strategies to optimize yield production with the appropriate agronomic or silvicultural approach in the field planting. Therefore, the objectives of this study were; to compare the root development of two different propagation seedlings of E. pellita; and to study the effect of various nitrogen concentration levels on two types of propagation of E. pellita seedlings. ResultsThe study was conducted using E. pellita seedlings from two types of propagation, namely, seed and stem cuttings, along with three different nitrogen concentrations (0, 50, and 200 kg N ha-1). Shoot biomass, root intensity (RI), total root intensity (TRI), root biomass, root length density (RLD), and specific root length (SRL) were recorded. Dried shoot biomass, RLD and SRL of E. pellita seedlings using stem cutting were significantly higher (P<0.05) compared to seed. Whereas, there were no significant differences (P>0.05) for root biomass, TRI and RI between the propagation types of E. pellita seedlings. Conclusions:E. pellita seedlings from stem cutting was greater in terms of root distribution compared to propagation by seeds at the nursery stage, and 50 kg N ha-1 was the optimal nitrogen concentration level from the considered levels to be applied to the E. pellita seedlings. The present study therefore provides more information and understanding on E. pellita for forest plantation companies in producing plant materials using stem cutting in a cost-effective and efficient manner. This would help the forest plantation companies in planning appropriate agronomic management in the future.

Optical Characterization of VLS+CVD Grown 3C-SiC Films by Non-Linear and Photoluminescence Techniques

2010 ◽  
Vol 645-648 ◽  
pp. 443-446 ◽  
Author(s):  
Georgios Manolis ◽  
Georgios Zoulis ◽  
Sandrine Juillaguet ◽  
Jean Lorenzzi ◽  
Gabriel Ferro ◽  
...  
Keyword(s):  
Nitrogen Concentration ◽  
Free Carrier ◽  
Free Carrier Absorption ◽  
Free Carrier Density ◽  
Temperature Dependences ◽  
Carrier Absorption ◽  
Data Investigation ◽  
The Impact ◽  
Sic Films

Thin 3C-SiC(111) epilayers grown on 6H-SiC(0001) substrate by VLS and CVD procedures were studied by low temperature photoluminescence (LTPL) and nonlinear optical techniques at room and low temperatures. Free carrier density ((0.3-7)×1017 cm-3) and nitrogen concentration (4×1016 cm-3) in the layers were determined from Raman and LTPL data. Investigation of non-equilibrium carrier dynamics by using transient grating and free carrier absorption techniques provided an ambipolar diffusion coefficient Da (~2.5 cm2/s) and carrier lifetime τR (2-4 ns) values at room temperature. The temperature dependences of Da and τR in 40-300 K range revealed the scattering processes in high density plasma as well the impact of defects.

scholarly journals Effects of water deficit on growth and physiology of young Conocarpus erectus L. and Ficus benjamina L. Saplings

2019 ◽  
Vol 48 (4) ◽  
pp. 1215-1221
Author(s):  
Zikria Zafar ◽  
Fahad Rasheed ◽  
Muhammad Abdullah ◽  
Mir Md Abdus Salam ◽  
Muhammad Mohsin
Keyword(s):  
Water Deficit ◽  
Biomass Production ◽  
Root Biomass ◽  
Growth Parameters ◽  
Co2 Assimilation ◽  
Total Biomass ◽  
Assimilation Rate ◽  
Ficus Benjamina ◽  
Co2 Assimilation Rate ◽  
Conocarpus Erectus

A greenhouse experiment was conducted to investigate the effects of water deficit on growth and physiological parameters of Ficus benjamina and Conocarpus erectus. The results revealed that all growth parameters such as plant height, stem diameter, no. of leaves, no. of branches and chlorophyll contents significantly decreased under water deficit condition. Interestingly, although leaf, stem and total biomass production and allocation decreased significantly under water deficit, but root biomass production and allocation increased significantly. Similarly, stomatal conductance to water vapor decreased significantly and CO2 assimilation rate remained similar to control under water deficit condition. Resultantly, a significant increase in water use efficiency was evident in both species under water deficit condition. These results suggested that, in spite of a significant decrease in biomass production, young Conocarpus erectus and Ficus benjamina can tolerate water deficit which is due to sustained CO2 assimilation rate and increase in root biomass.

scholarly journals Phosphorus and Zinc Fertilization Influence Crop Growth Rates and Total Biomass of Coarse vs. Fine Types Rice Cultivars

Agronomy ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1356
Author(s):  
Amanullah ◽  
Inamullah ◽  
Jawaher Alkahtani ◽  
Mohamed Soliman Elshikh ◽  
Mona S. Alwahibi ◽  
...  
Keyword(s):  
Growth Rates ◽  
Positive Impact ◽  
Oryza Sativa L ◽  
Crop Growth ◽  
Growth Stages ◽  
Total Biomass ◽  
Continuous Cropping ◽  
Rice Cultivars ◽  
Rice Genotypes ◽  
The Impact

Under the rice–wheat cropping system (RWS), the continuous cropping of rice (Oryza sativa L.) and wheat (Triticum aestivum L.) deplete soil fertility, and reduce crop growth and total rice biomass. In RWS, both phosphorus (P) and zinc (Zn) deficiencies are considered important nutritional constraints for reducing rice crop growth rates (CGR) and total biomass/biological yield (BY). The objective of this experiment was to investigate the impact of phosphorus (0, 40, 80, 120 kg P ha−1) and zinc rates (0, 5, 10, 15 kg Zn ha−1) on CGR and BY of three rice genotypes [fine (Bamati-385) versus coarse (Fakhre-e-Malakand and Pukhraj)] in Northwestern Pakistan during summer 2011 (Y1) and 2012 (Y2). The results revealed that higher CGR at various growth stages and total BY was obtained with the integrated use of higher phosphorus (80 and 120 kg P ha−1) and zinc rates (10 and 15 kg Zn ha−1). The lower CGR and BY were recorded when P and Zn were not applied (control) or when P and Zn were applied alone. In the case of rice genotypes, the highest CGR and BY were recorded for the hybrid rice (Pukhraj) than the other two genotypes. The CGR was increased to the highest level at the heading stage as compared to tillering and physiological maturity. The increase in CGR had a positive impact on the total BY of rice cultivars. The increase in BY had a positive relationship with grain yield and grower’s income. It was concluded from the study that the combined application of higher P and Zn rates to the coarse rice genotypes (Fakhre-e-Malakand and Pukhraj) could increase CGR, total BY, crop productivity and profitability.

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