scholarly journals Mycorrhizal Colonization Increases Herbicide Toxicity in Apple

1994 ◽  
Vol 119 (6) ◽  
pp. 1255-1260 ◽  
Author(s):  
C. Hamel ◽  
F. Morin ◽  
A. Fortin ◽  
R.L. Granger ◽  
D.L. Smith
Keyword(s):  
Relative Elongation ◽  
Dry Mass ◽  
Mycorrhizal Colonization ◽  
Mass Reduction ◽  
Apple Rootstocks ◽  
Apple Trees ◽  
Toxic Response ◽  
Herbicide Treatments ◽  
Mycorrhizal Plants

Herbicides are increasingly used in orchards. Since apple trees strongly depend on mycorrhizae, the effects of three commonly used herbicides on the host plant and endophyte were examined. Symbiosis between tissue-cultured P16 apple rootstocks and Glomus versiforme (Karsten) Berch was established under greenhouse conditions. Simazine (1, 2, 10, and 20 μg a.i./g), dichlobenil (1, 5, 10, and 25 μg a.i./g), paraquat (0.5, 1, 10, and 100 μg a.i./g), or water was applied to mycorrhizal and nonmycorrhizal plants as a soil drench. The response of mycorrhizal plants to herbicide was greater, and the relative elongation rate was more sharply reduced in mycorrhizal (76%) than in nonmycorrhizal plants (33%). Six weeks after herbicide application, dry mass reduction due to herbicides was similar (39% and 36%) for mycorrhizal and nonmycorrhizal plant shoots, respectively, while root dry mass reduction was larger for mycorrhizal (63%) than nonmycorrhizal plants (46%). None of the herbicide treatments affected root colonization. However, an in vitro hyphal elongation test with G. intraradices Schenck & Smith and herbicide-amended (0, 1, 10, 100, and 1000 μg a.i./g) gellan gum solidified water showed that either dichlobenil or paraquat, even at the lowest concentrations, could significantly reduce hyphal elongation. Simazine did not affect hyphal elongation in vitro, a result suggesting that improved absorption capacity of mycorrhizae explains, at least in part, the increased phytotoxicity of some herbicides. It was found that plant mortality was higher among mycorrhizal than nonmycorrhizal apple trees for all herbicide treatments. The increased CO2 assimilation rates of dichlobenil-treated mycorrhizal plants contrasted with the decreased rates of control plants measured 1 week after dichlobenil treatment. This indicates a physiological interaction between mycorrhizal colonization and dichlobenil in the toxic response of apple plants. Chemical names used: 2-chloro-4,6-bis-ethylamino-s-triazine (simazine), 2,6-dichlorobenzonitrile (dichlobenil), 1,1'-dimethyl-4,4'bipyridinium (paraquat).

scholarly journals CARBON ECONOMY IN SOUR ORANGE IN RELATION TO MYCORRHIZAL COLONIZATION AND PHOSPHORUS STATUS

HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 579d-579
Author(s):  
David M. Eissenstat ◽  
James H. Graham ◽  
James P. Syvertsen ◽  
Diana L. Drouillard
Keyword(s):  
Leaf Area ◽  
Root Length ◽  
Dry Mass ◽  
Mycorrhizal Colonization ◽  
Sour Orange ◽  
P Nutrition ◽  
Relative Growth Rates ◽  
Whole Plant ◽  
Mycorrhizal Plants ◽  
C Partitioning

The effects of phosphorus (P) and of the mycorrhizal (M) fungus, Glomus intraradix, on the carbon (C) economy of sour orange (citrus aurantium L.) were determined during and following active M colonization. There were four treatments: mycorrhizal seedlings grown at standard-strength P (M1) and nonmycorrhizal (NM) plants grown at 1, 2 and 5 times standard-strength P (NM1, NM2 and NM5). Mycorrhizal colonization, tissue dry mass, P content, root length, leaf area, 14C partitioning and rate of c assimilation (A) were determined in five whole-plant harvests from 6 to 15 wks of age. In contrast to the effects of P nutrition on C economy in sour orange, M effects were generally subtle. Mycorrhizae increased the root biomass fraction, the root length/leaf area ratio, and the percent of 14C recovered from belowground components. Mycorrhizal plants had a higher percentage of belowground 14C in the respiration and soil fractions than did NM plants of equivalent P status. Mycorrhizal plants tended to have enhanced A at 8 wks but not at 7 or 12 wks. This temporarily enhanced A of M plants did not fully compensate for their greater belowground C expenditure, as suggested by apparently lower relative growth rates of M than NM plants of equivalent P status. Problems of interpreting the dynamic effects of mycorrhizae on C economy that are independent of p nutrition are discussed.

scholarly journals 207 Mycorrhizal Enhancement of the Physiology and Growth of Micropropagated Chile Ancho Pepper (Capsicum annuum L. cv. San Luis) Plantlets during Acclimatization and Post-acclimatization

HortScience ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 426E-426
Author(s):  
Andres A. Estrada-Luna ◽  
Fred T. Davies ◽  
Jonathan N. Egilla
Keyword(s):  
Peak Stress ◽  
Dry Mass ◽  
Mycorrhizal Colonization ◽  
Ex Vitro ◽  
Poor Growth ◽  
San Luis ◽  
Leaf Chlorophyll ◽  
Leaf Dry Mass ◽  
Relative Water

The role of mycorrhiza fungi during acclimatization and post-acclimatization of micropropagated chile ancho plantlets was characterized through physiological and plantlet development changes. Regardless of mycorrhizal colonization, the pepper plantlets had initially low photosynthetic rates and poor growth following transplanting ex vitro. During the first days of acclimatization, water deficits occurred as evidenced by drastic reductions in relative water content. Consequently, transpiration rates and stomatal conductance (gs) declined, confirming that in vitro formed stomata were functional, thus avoiding excessive leaf dehydration and plant death. Mycorrhiza had a positive effect on gas exchange as early as day 7 and 8, as indicated by increasing photosynthesis (A) and gs. Mycorrhizal plantlets had reduced levels of abscisic acid (ABA) during peak stress (6 days after transplanting ex vitro), which corresponded with subsequent increases in gs and A. During acclimatization, A increased in both non-colonized and colonized plantlets, with greater rates observed in mycorrhizal plantlets. During post-acclimatization, mycorrhiza colonized 45% of the roots of pepper plantlets and enhanced plant growth by increasing leaf area, leaf dry mass, and fruit number. Mycorrhiza also enhanced total leaf chlorophyll content, A, and nutrient uptake of pepper plantlets, particularly N, P, and K. Early mycorrhizal colonization produced important benefits, which helped ex vitro transplanted plantlets recover during acclimatization and enhance physiological performance and growth during post-acclimatization.

Methods of experimental polyploidization and their use in apple breeding

2020 ◽  
Vol 62 ◽  
pp. 85-90
Author(s):  
L. V. Tashmatova ◽  
O. V. Matsneva ◽  
T. M. Khromova ◽  
V. V. Shakhov
Keyword(s):  
Exposure Time ◽  
Cell Walls ◽  
Prolonged Exposure ◽  
Ornamental Plants ◽  
Colchicine Treatment ◽  
Apple Trees ◽  
Open Ground ◽  
High Concentrations ◽  
Diploid Gametes

The article presents methods of experimental polyploidy of fruit, berry and ornamental plants. The purpose of this review is to highlight the problems and prospects of polyploidization of plants in the open ground and in vitro culture and the possibility of their application for apple trees. For the purpose of obtaining apple tetraploids as donors of diploid gametes, seed seedlings were treated with a solution of colchicine in concentrations of 0.1-0.4 % for 24 and 48 hours. Colchicine concentrations of 0.3 % and 0.4 % at 48 hours of treatment had a detrimental eff ect on their development. As a result, tetraploids and chimeras were obtained from seeds from free pollination of the varieties Orlik, Svezhest, Kandil Orlovsky, as well as from seeds obtained from crossing the varieties Svezhest×Bolotovskoe, Moskovskoe Оzherel’e×Imrus, Girlyanda×Venyaminovskoe. The optimal concentration of colchicine was 0.1 %. Methods of colchicine treatment have been studied: 1) adding to the nutrient medium, colchicine concentration: 0.01%, 0.02%, exposure time 24h-19 days; 2) applying amitotic solution to the growth point, colchicine concentration: 0.1 %, 0.2 %, exposure time 24h-7 days. To increase the penetration of colchicine through the cell walls, a 0.1 % dimexide solution was used. Studies have shown that high concentrations and prolonged exposure to colchicine reduce the viability of explants.

Effects of Weed Control in Established Alfalfa (Medicago sativa) on Forage Yield and Quality

Weed Science ◽  
1987 ◽  
Vol 35 (4) ◽  
pp. 564-567 ◽  
Author(s):  
Dennis R. Cosgrove ◽  
Michael Barrett
Keyword(s):  
Medicago Sativa ◽  
Weed Control ◽  
Stand Density ◽  
Forage Yield ◽  
Control Measures ◽  
Acid Detergent Fiber ◽  
Yield And Quality ◽  
Herbicide Treatments ◽  
Forage Yields

The effects of weed control measures in established alfalfa (Medicago sativaL.) on forage yield and quality were investigated at three sites with varying alfalfa densities and weed populations. Herbicide treatments were 0.56 and 1.12 kg/ha metribuzin [4-amino-6-(1,1-dimethylethyl)-3-(methylthio)-1,2,4-triazin-5(4H)-one] applied in fall or spring, respectively, 1.68 kg/ha pronamide [3,5-dichloro (N-1,1-dimethyl-2-propynyl)benzamide] applied in fall, and combinations of these treatments. First-harvest forage yields (weeds plus alfalfa) were either reduced or unchanged by herbicide treatments. Total forage yield was not altered by the herbicide treatments, but first-harvest and total alfalfa yield as well as first-harvest forage protein content were increased by several treatments, depending on stand density and weed pressure. Little effect was observed on in vitro digestible dry matter or acid detergent fiber content.

Use of Toxicokinetics in Risk Assessment Based on In Vitro Data

1993 ◽  
Vol 21 (2) ◽  
pp. 173-180
Author(s):  
Gunnar Johanson
Keyword(s):  
Risk Assessment ◽  
Whole Body ◽  
External Exposure ◽  
Target Dose ◽  
Toxic Response ◽  
Route Of Exposure ◽  
Vitro Data ◽  
In Vitro Data

This presentation addresses some aspects of the methodology, advantages and problems associated with toxicokinetic modelling based on in vitro data. By using toxicokinetic models, particularly physiologically-based ones, it is possible, in principle, to describe whole body toxicokinetics, target doses and toxic effects from in vitro data. Modelling can be divided into three major steps: 1) to relate external exposure (applied dose) of xenobiotic to target dose; 2) to establish the relationship between target dose and effect (in vitro data, e.g. metabolism in microsomes, partitioning in tissue homogenates, and toxicity in cell cultures, are useful in both steps); and 3) to relate external exposure to toxic effect by combining the first two steps. Extrapolations from in vitro to in vivo, between animal and man, and between high and low doses, can easily be carried out by toxicokinetic simulations. In addition, several factors that may affect the toxic response by changing the target dose, such as route of exposure and physical activity, can be studied. New insights concerning the processes involved in toxicity often emerge during the design, refinement and validation of the model. The modelling approach is illustrated by two examples: 1) the carcinogenicity of 1,3-butadiene; and 2) the haematotoxicity of 2-butoxyethanol. Toxicokinetic modelling is an important tool in toxicological risk assessment based on in vitro data. Many factors, some of which can, and should be, studied in vitro, are involved in the expression of toxicity. Successful modelling depends on the identification and quantification of these factors.

Survival and Function of Fibroblasts Stored as Stock Cultures at a Non-freezing Temperature

1993 ◽  
Vol 21 (2) ◽  
pp. 206-209
Author(s):  
Anders H. G. Andrén ◽  
Anders P. Wieslander
Keyword(s):  
Cell Growth ◽  
Cell Line ◽  
Cell Lines ◽  
Fibroblast Cell ◽  
Freezing Temperature ◽  
Mouse Fibroblast ◽  
Toxic Response ◽  
Normal Manner ◽  
And Function

Cytotoxicity, measured as inhibition of cell growth of cultured cell lines, is a widely used method for testing the safety of biomaterials and chemicals. One major technical disadvantage with this method is the continuous routine maintenance of the cell lines. We decided to investigate the possibility of storing stock cultures of fibroblasts (L-929) in an ordinary refrigerator as a means of reducing the routine workload. Stock cultures of the mouse fibroblast cell line L-929 were prepared in plastic vials with Eagle's minimum essential medium. The vials were stored in a refrigerator at 4–10°C for periods of 7–31 days. The condition of the cells after storage was determined as cell viability, cell growth and the toxic response to acrylamide, measured as cell growth inhibition. We found that the L-929 cell line can be stored for 2–3, weeks with a viabilty > 90% and a cell growth of about 95%, compared to L-929 cells grown and subcultured in the normal manner. The results also show that the toxic response to acrylamide, using refrigerator stored L-929 cells, corresponds to that of control L-929 cells. We concluded that it is possible to store L-929 cells in a refrigerator for periods of up to 3 weeks and still use the cells for in vitro cytotoxic assays.

Herbicide Effects on Weed Control and Shoot Growth of Young Apple (Malus sylvestris) and Peach (Prunus persica) Trees

1994 ◽  
Vol 8 (4) ◽  
pp. 840-848 ◽  
Author(s):  
Chester L. Foy ◽  
Susan B. Harrison ◽  
Harold L. Witt
Keyword(s):  
Shoot Growth ◽  
Field Experiments ◽  
Prunus Persica ◽  
Weed Species ◽  
Apple Trees ◽  
Herbicide Treatments ◽  
One Year ◽  
Broadleaf Species ◽  
Old Trees ◽  
Peach Trees

Field experiments were conducted at two locations in Virginia to evaluate the following herbicides: alachlor, diphenamid, diuron, metolachlor, napropamide, norflurazon, oryzalin, oxyfluorfen, paraquat, pendimethalin, and simazine. One experiment involved newly-transplanted apple trees; the others, three in apple and one in peach trees, involved one-year-old trees. Treatments were applied in the spring (mid-April to early-May). Control of annual weed species was excellent with several treatments. A broader spectrum of weeds was controlled in several instances when the preemergence herbicides were used in combinations. Perennial species, particularly broadleaf species and johnsongrass, were released when annual species were suppressed by the herbicides. A rye cover crop in nontreated plots suppressed the growth of weeds. New shoot growth of newly-transplanted apple trees was increased with 3 of 20 herbicide treatments and scion circumference was increased with 11 of 20 herbicide treatments compared to the nontreated control. Growth of one-year-old apple trees was not affected. Scion circumference of one-year-old peach trees was increased with 25 of 33 herbicide treatments.

scholarly journals Do minke whales (Balaenoptera acutorostrata) digest wax esters?

1995 ◽  
Vol 74 (5) ◽  
pp. 717-722 ◽  
Author(s):  
Erling S. Nordøy
Keyword(s):  
Energy Density ◽  
Dry Matter ◽  
General Pattern ◽  
Dry Mass ◽  
Wax Esters ◽  
Gut Contents ◽  
Wax Ester ◽  
Balaenoptera Acutorostrata ◽  
Minke Whales

Mammals are known to utilize wax esters with an efficiency of less than 50%. The purpose of the present study was to examine whether or not minke whales (Balaenoptera acutorostrata), which at times may eat considerable amounts of wax-ester-rich krill, represent an exception to this general pattern. Samples of fresh undigested forestomach, as well as colon, contents were obtained from minke whales (n5) that had been feeding on krill (Thysanoessa inermis) for some time. The samples were analysed for dry mass, energy density, lipid content and the major lipid classes, including wax esters. The concentrations of wax esters were compared with previous estimates of dry-matter disappearance of the same type of prey using anin vitrotechnique, to calculate the dry-matter digestibility of wax esters (DMDwax). Wax esters contributed 21% of the energy and 47% of total lipids in the krill diet. The energy density of gut contents decreased by 50% after their passage from forestomach to the end of the colon. The DMDwaxwas 94·1 (SD 2·8)% (n5). This high DMDwaxand the occurrence of fatty alcohols, one of the products of wax-ester hydrolysis, in faeces show that minke whales are very efficient digesters of wax esters and absorb most of the energy-rich products of this process.

scholarly journals FUNGOS MICORRÍZICOS ARBUSCULARES E DOSES DE FÓSFORO NO DESENVOLVIMENTO DE MUDAS DE GUANANDI

Nativa ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 246
Author(s):  
Edilson Nonato Da Silva ◽  
Aline Torquato Tavares ◽  
Cândida Pereira Da Silva ◽  
Tiago Alves Ferreira ◽  
João Victor Gonçalves Carline ◽  
...  
Keyword(s):  
Mycorrhizal Fungi ◽  
Arbuscular Mycorrhizal ◽  
Dry Mass ◽  
Mycorrhizal Colonization ◽  
University Campus ◽  
Experimental Station ◽  
Calophyllum Brasiliense ◽  
Shoot Mass ◽  
Different Levels ◽  
Forest Engineering

O experimento foi realizado na Estação Experimental de Engenharia Florestal do Campus Universitário de Gurupi, Universidade Federal do Tocantins (UFT), com objetivo de determinar a melhor dose de fósforo na presença de fungos arbusculares em mudas de guanandi (Calophyllum brasiliense Camb.) O delineamento experimental utilizado foi inteiramente casualizado com três repetições em esquema fatorial 6 x 2. Os tratamentos foram seis doses de fósforo (0; 400; 800; 1200; 1600 e 2000 g de P2O5 por m³) no substrato na presença e ausência de Fungos Micorrízos Arbusculares (FMAs). As características avaliadas foram altura das plantas, diâmetro do caule, massa seca da parte aérea (MSPA), massa seca da raiz (MSR), massa seca total (MST) e colonização micorrízica. Os diferentes níveis de adubação influenciaram a colonização micorrízica arbuscular. Nas doses 400 e 1600 g de fósforo por m3 de substrato observou-se maior porcentagem de colonização. A altura e o diâmetro das plantas foram significativamente afetados pela presença de P2O5. A massa seca da parte aérea e massa seca total não é afetada por doses de P2O5. O melhor desempenho das mudas de C. brasiliense ocorreu aos 90 dias com dose de 1.421 g de P2O5 por m3 de substrato.Palavras-chave: Calophyllum brasiliense Camb., adubação, micorrização. MYCORRHIZAL FUNGI AND PHOSPHORUS DOSES IN THE DEVELOPMENT OF GUANANDI SEEDLINGS ABSTRACT:The experiment was carried out at the Forest Engineering Experimental Station of the Federal University of Tocantins (UFT), University Campus of Gurupi, with the objective of determining the best dose of phosphorus in the presence of arbuscular fungi in guanandi (Calophyllum brasiliense Camb. The experimental design was completely randomized with three replicates in a 6 x 2 factorial scheme. The treatments were six doses of phosphorus (0, 400, 800, 1200, 1600 and 2000 g of P2O5 per m³) on the substrate in the presence and absence of Arbuscular mycorrhizal fungi (FMAs). The evaluated characteristics were plant height, stem diameter, shoot dry mass (MSPA), root dry mass (MSR), total dry mass (MST) and mycorrhizal colonization. The different levels of fertilization influenced arbuscular mycorrhizal colonization. At 400 and 1600 g of phosphorus per m3 of substrate, a higher percentage of colonization was observed. The height and diameter of the plants were significantly affected by the presence of P2O5. Dry shoot mass and total dry mass are not affected by P2O5 doses. The best performance of C. brasiliense seedlings occurred at 90 days with a dose of 1421 g of P2O5 per m3 of substrate.Keywords: Calophyllum brasiliense Camb., fertilization, mycorrhization. DOI:

scholarly journals In vitro development of sugarcane seedlings using ethephon or gibberellin

2018 ◽  
Vol 8 (2) ◽  
pp. 389-395
Author(s):  
Luciane De Siqueira Mendes ◽  
Marcia Eugenia Amaral Carvalho ◽  
Willian Rodrigues Macedo ◽  
Paulo Roberto de Camargo e Castro
Keyword(s):  
Gibberellic Acid ◽  
Dry Mass ◽  
In Vitro Production ◽  
In Vitro Development ◽  
Reduced Height ◽  
Potential Strategy ◽  
Vitro Development ◽  
Vitro Production ◽  
Different Doses

The use of plant growth regulators is directly related to the success of in vitro propagation, which is an advantageous alternative to obtain seedlings on a commercial scale. This study aimed to evaluate the in vitro development of ‘IAC 95-5000’ sugarcane seedlings after the addition of different doses of ethephon (0, 25, 50, 100 and 200 mg L-1) or gibberellic acid (0, 2.5, 5.0, 7.5 and 10.0 mg L-1) to the culture medium. Ethephon increased the number of tillers (up to 231.70%), reduced height of the main tiller (44.66 to 60.47%), and did not affect the shoot´s fresh and dry mass. On the other hand, gibberellin decreased the number of tillers and negatively changed biomass partitioning. It is concluded that the use of ethephon is a potential strategy to enhance in vitro production of ‘IAC 95-5000’ sugarcane seedlings, since it increased the number of usable shoots in subsequent subcultures, and its effects on height reduction can be reversible. However, the use of the tested doses of gibberellic acid is not recommended, because it impaired seedling development of this sugarcane variety.

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