Red Clover Roots Research Articles

Forage Legumes Preferred by the Clover Root Curculio and Preferences of the Curculio and Root Lesion Nematodes for Species of Trifolium and Medicago12

Greenhouse tests on feeding preferences of larvae and adults of the clover root curculio, Sitona hispidula (F.), for 5 forage legumes indicated that adults preferred white, alsike, and red clover, alfalfa, and birds foot trefoil in descending order. Larvae preferred red, white, and alsike clover roots over those of alfalfa and birds foot trefoil. Field and greenhouse screening trials to determinc possible sources of resistance in Medicago and Trifolium species to attack by the curculio and root lesion nematodes, Pratylenchus spp., indicated little promise of resistance in any of the species tested.

EFFECT OF NEMATICIDES ON ROOT LESION NEMATODES AND FORAGE LEGUME YIELDS

A field study was made on the effectiveness of seven nematicides in reducing root lesion nematode (Pratylenchus spp.) numbers in soil and roots of alfalfa, red clover, and birdsfoot trefoil. Each of the nematicides significantly reduced the number of nematodes recovered from soil 2 and 14 months after seeding, and from roots 4 and 16 months after seeding. Nematicide treatments significantly increased first cut (August) yields of red clover, alfalfa, and birdsfoot trefoil in the seeding year by 55, 28, and 47%, respectively. Total yields for the seeding year were increased by 22, 22, and 40%, respectively. Sixteen months after seeding, significantly more nematodes were recovered from birdsfoot trefoil roots than from red clover, and more from red clover than from alfalfa. The recovery of Fusarium spp. from rootlets 4 months after seeding was not affected by nematicide treatments; however, Fusarium spp. were recovered less frequently from birdsfoot trefoil than from red clover or alfalfa rootlets.

27. 飼料作物の生理生態学的研究 : 第IV報 赤クローバおよびアルフアルフアの刈取時期と越冬中における根部の炭水化物との関係(談話会年次講演会講演要旨昭和37年度)

27. 飼料作物の生理生態学的研究 : 第IV報 赤クローバおよびアルフアルフアの刈取時期と越冬中における根部の炭水化物との関係(談話会年次講演会講演要旨昭和37年度)

TWO NEW SPECIES OF THE GENUS HELICOTYLENCHUS STEINER, 1945 (NEMATODA: HOPLOLAIMINAE)

Helicotylenchus canadensis n. sp., and H. cairnsi n. sp., commonly associated with red clover (Trifolium pratense L.) root zone in the province of Quebec, Canada, are described herein.

Nematodes in relation to plant growth. III. Pratylenchus penetrans (Cobb) in tree crops, potatoes and red clover.

The results of five rotation and fumigation experiments together with additional field surveys show that Pratylenchus penetrans is a serious cause of sickness symptoms and has crop rotational effects on many woody plants, red clover and potatoes. It is wide-spread in light and medium soils especially in nurseries and fruit orchards; 9% of the fields examined contained more than 100 specimens per 100 ml. of soil. Results demonstrate a significant linear relationship between the log. of initial population density or of population density within roots and growth deficit of susceptible crops. There was some indication that heavy infestations of P. penetrans in red clover roots impaired nitrogen fixation. The cultivation of rye, oats and red clover should be avoided in infested land as they are good hosts. Beet or mangolds are advised to be grown on infested arable land just before potatoes or red clover as they suppress P. penetrans. Nematicides give effective control of P. penetrans but their cost restricts their use to land growing valuable crops. Other plant nematode relationships indicated by the results were that grass, red clover, oats, rye, and swede were efficient hosts of Tylenchorhynchus dubius; red clover was a good host of Rotylenchus robustus; potatoes were a better host for Meloidogyne hapla than red clover, mangold or oats; mangold was an efficient host of P. neglectus but suppressed P. penetrans and P. crenatus; mangold and grass were efficient hosts of Paratylenckus spp. D.J.H. (Abstract retrieved from CAB Abstracts by CABI’s permission)

The Economic Importance of the Clover Root Borer

Control of the clover root borer, Hylastinus obscurus (Marsh.), by single or multiple applications of insecticides, did not increase survival of red clover to an economically important level in seven field and insectary experiments conducted in New York during 1954 to 1957. Borer control appeared to have no effect whatever on first-cutting hay yields in the first harvest year and little, if any, on the second cutting. The severity of red clover root rot was correlated with the severity of borer injury, but the severity of root rot was not reduced as much, proportionately, by control of the borer, as was the severity of borer injury.

A Species of Endogone from Corn Causing Vesicular-Arbuscular Mycorrhiza

SUMMARYAn Endogone causing vesicular-arbuscular mycorrhiza has been found on corn in Illinois. The species is similar to the unnamed Endogone reported by Mosse from strawberry in England. Extra-matrical chlamyodospores were common in soil collected from around corn roots. Corn plants inoculated with chlamydospores developed typical vesicular-arbuscular mycorrhiza. Sporocarps and extra-matrical chlamydospores were produced on hyphae attached to infected roots. Sporocarps developed abundantly on roots of inoculated plants grown in sterilized soil, but they were rarely found in field soil. The main source of inoculum in field soil appears to be extra-matrical chlamydospores. The fungus also produced vesicular-arbuscular mycorrhiza in roots of strawberry, onion, red clover and soybeans.

Rhizobium numbers in the rhizospheres of red clover and paspalum in relation to soil treatment and the numbers of bacteria and fungi

Estimates of the numbers of fungi, bacteria, and clover rhizobia in the rhizospheres of red clover and paspalum grown in a krasnozem (pH 4.8) have shown that the stimulation of fungi and general soil bacteria is limited to that soil in immediate contact with the roots. The stimulation of rhizobia by the red clover roots appears to be more extensive, with high numbers occurring in the soil, even 10–20 mn from the roots. Paspalum roots increased the numbers of rhizobia in the soil immediately surrounding the roots, but to a lesser degree than did clover. Amelioration of the soil increased the levels of bacteria and fungi in the soil and in the rhizosphere, with spectacular increases in the numbers of rhizobia in the rhizosphere of red clover.

AMINO ACIDS AS NITROGEN SOURCES FOR THE GROWTH OF EXCISED ROOTS OF RED CLOVER

SummaryTwo clones of excised roots of red clover have been established and maintained in culture. One of these (Clone A) was selected as showing a satisfactory level of growth in the standard medium and the other (Clone Z) as being relatively resistant to growth inhibition by L‐aspartic acid.L‐aspartic acid, L‐asparagine, L‐glutamic acid and L‐α‐alanine were each effective as sole sources of nitrogen for the growth of excised roots of Clone Z but not for roots of Clone A.L‐aspartic acid, L‐glutamic acid and L‐α‐alanine each depressed the growth of the roots when supplied in the presence of nitrate. Roots of Clone Z were more resistant to growth inhibition by these amino acids than roots of Clone A.L‐valine and glycine were ineffective as sole sources of nitrogen for growth of roots of either clone and were inhibitory to growth when supplied in the presence of nitrate.L‐arginine was effective as a sole source of nitrogen for the growth of roots of both Clone A and Clone Z. With increasing concentrations of the amino acid supplied in the presence of nitrate, growth of roots of both clones was first stimulated and then depressed.In experiments with Clone A, it was shown that D‐arginine was similar to L‐arginine in its effects on growth, but that DL‐alanine was more inhibitory than L‐alanine.When amino acids were supplied as sole sources of nitrogen, growth was always inferior to that obtained with nitrate. Urea, however, supported a level of growth similar to that supported by nitrate.The technique of excised root culture is suited to the study of the utilization of amino acids as nitrogen sources for plant growth. Nitrogen deficiency can be developed rapidly in excised root‐tips and the technique permits work with clonal material under sterile, controlled conditions. A number of investigations of the nutrient requirements of excised roots have included an examination of effects of amino acids on growth (White, 1937, 1939; Baylor and Rappaport, 1950; Boll, 1954; Skinner and Street, 1954; Roberts and Street, 1955). In these cases the primary objective has been to test amino acids as potential growth factors rather than as nitrogen sources for the roots. However, Skinner and Street (1954), working with excised roots of groundsel, established that L‐arginine, L‐ornithine, L‐citrulline and L‐lysine, which were stimulatory to growth in the presence of nitrate, were also effective in supporting growth in the absence of other nitrogen sources.

Injury of Clover Root Curculios to Red Clover in New Jersey1

A 3-year survey of red clover fields in New Jersey showed that high populations of Sitona hispidula (F.) and S. flavescens Marsham were present throughout the State and extensive larval feeding was observed on the roots of seedling and secondyear stands. Sitonids were found, by the use of a soil-filtering process, to be the most numerous of all insects attacking red clover roots. During 1956 and 1957 the average number of feeding scars produced on roots by sitonids during the larval period was 1.18 and 1.26, respectively, or an overall average of 1.22 feeding scars per sitonid. Using this figure to estimate sitonid larval populations from feeding-scar data in plots that were sampled after the sitonid larvae had completed their development and had emerged from the soil as adults, populations of 50 or more per square foot were not unusual and populations as high as 124 per square foot have been found. Estimated populations on a Statewide basis averaged about 73 sitonids per square foot.

Studies of the Vertical Distribution of the Clover Root Borer in Roots of Red Clover in Relation to Progression of the Season

Red clover roots were sampled periodically from a first-harvest-year field, cut into ½-inch segments starting at the top of each root, and examined for numbers of the clover root borer, Hylastinus obscurus (Marsh.) (Coleoptera: Scolytidae). For the period June 12 to October 12, 1957, the seasonal average depths were: larvae, 0.76 inch; pupae, 0.84 inch; and adults, taken after the first callow individual appeared, 0.82 inch. The pooled average depth of these stages increased in a linear manner as the season progressed. Using head-capsule width as a criterion of size, the depth of larvae collected on August 22 was directly proportional to their size. Temperature appeared not to be a controlling factor for the depth at which the combined stages were found. In the absence of a temperature effect, maturity seemed to be the factor that had the greatest influence on the depth at which larvae were located.

Effect of Root Size and Soil Moisture on the Number of Clover Root Borers Present in Red Clover Roots

During 2 consecutive years, similar field experiments were condoled in New York to study the effects of red clover ( Trifolium pratense L.) root size and percentage available soil moisture on numbers of the clover root borer, Hylastinus obscurus (Marsh.) (Scolytidae: Coleoptera). In 1956, as soil moisture decreased, borer numbers increased; as root size increased, borer numbers increased. A multiple regression analysis indicated that either root size or soil moisture could account for most of the variation in borer numbers, because the two independent variables were closely correlated to each other: as soil moisture decreased, root size. Increased. In 1957, it was found that root size alone was responsible for the majority of the variation in borer numbers. On the basis of these data and differences in the number of areas sampled, the distance between sampling areas, Uniformity, and ranges of soil moisture in 1956 as compared with 1957, the conclusion was reached that root size has a more direct influence than soil moisture on borer numbers. Soil moisture is believed to indirectly affect borer numbers owing to its influence on root size.

Growth Responses of Excised Roots of Red Clover

1. Sucrose was the only sugar which supported a high growth rate of the excised root clone 1 of the Dorset Marlgrass strain of red clover (Trifolium pratense L.). D-fructose, D-glucose, and maltose supported a lower level of growth. The other sugars tested were inactive as carbon sources. Additions of D-xylose, D-mannose, and D-arabinose strongly inhibited the growth of roots when simultaneously supplied with sucrose. 2. Nitrate was the most effective source of nitrogen tested. Ammonium, urea, and L-glutamine as nitrogen sources supported a lower level of growth. The optimum pH range for growth was the same whether nitrate or ammonium was used as nitrogen source. 3. The omission of any constituent from White's vitamin mixture limited growth. The most marked growth depression followed the omission of niacin. Niacin plus thiamine was more effective than any other combination of two factors. There was no evidence that pyridoxine and niacin could partially replace one another. 4. Indoleacetic acid (IAA), acco...

Observations on fungi associated with plant roots.

Plant age and soil type influence the nature of the fungal flora associated with plant roots. Total numbers of fungi in the rhizosphere of wheat, as determined by the dilution technique, increased with plant age but the degree of fungal stimulation appeared to depend upon soil type. Penicillia and certain species of the Mucorales were relatively more abundant on the root surface and in the rhizosphere at the seedling stage than at later stages of growth. Species of Fusarium and/or Cylindrocarpon (depending upon soil type) and various sterile dark fungi were predominant on the roots of healthy red clover and wheat, but were relatively rare in rhizosphere and non-rhizosphere soil.

Relation of a Large Soil-Borne Spore to Phycomycetous Mycorrhizal Infections

SUMMARYA large, yellow, one-celled spore 291–812μ in diameter was found to be common in Illinois soils. Inoculation studies showed that it causes a mycorrhizal infection of the phycomycete type. The appearance of the spore and attached hyphae suggest that it is a sexual stage. These spores have been separated in quantity from soil by wet sieving and decanting. They have been surface sterilized and pure cultures grown from them. Spores germinated by producing germ tubes. Hyphae varied from coarse, irregular and coenocytic to fine, smooth and regularly septate. It was grown on various types of agar media, but only a limited growth, not exceeding 22 mm in length, was obtained. Somewhat better growth was obtained in water culture with non-sterile soil organic matter or bits of hemp seed.When artificial inoculations were made, hyphae from these spores penetrated plant roots. Hyphae were intracellular as they passed through the outer cortex and when they reached the inner cortex they became intercellular as they grew through the root. Arbuscles were produced in cortical cells just outside the endodermis. Hyphae within the roots were non-septate. After penetration, tight bunches of echinulate spores formed on the external mycelium. The internal and external vesicles often associated with this type of mycorrhiza in the field have not formed in artificial inoculations.Cross inoculation experiments utilizing spores from known sources indicate a wide host range. What appeared to be the same strain infected roots of red clover, corn, strawberry, and sweet clover.

Studies on the broken root of some crops caused by the formation of the icicle layer and on the protecting methods : 2. On the injuries of the certain kinds of crops

The results of investigation about the broken roots of red clover, alfalfa, yellow sweet clover hairy vetch, orchadgrass, timothy, rye, and rape in frozen soil are as follows. Red clover (Fig. 1. a.) : The root system is divided into two parts, upper and lower, by the pulling action of the icicle layer. Alfalfa (Fig. 1. b.), yellow sweet clover : These are similar as the case of red clover, but in early spring some heaved plants fall down and die. Hairy vetch (Fig. 1. c.) : Main roots are seldom cut, while branch roots are cut. Orchardgrass, timothy (Fig. 1. d.) : The greater part of the root system freezes to become a frozen block and the icicle layer is formed as if avoiding this block. Rye (Fig. 1.e.) : It is similar in the case of orchardgrass. But the injury of rye plant is greater than that of orchardgrass because of its shallowness of the root system. Rape (Fig. 1. f.) : Damaged plants are hardly found and in some cases holes around the main roots are found. From these observations we obtain knowledges as follows: (a) The injured manifestation of broken roots varies according to the kinds of plants or of types of their root systems. (b) The intensity of injury varies according to the development of root system of the plant. And therefore it concerns to the planting time, the manuring, the fertilizing, the planting rote etc. (C) The mechanism of the breaking of the roots consists of following two stages: 1 st stage; The several inches of the soil from surface freezes to from the concrete layer, and at the same time it fastens the roots in this layer. 2nd stage ; When the frozen concrete layer is heaved by the action of the icicle layer, the root systems in the unfrozen soil layer is pulled up from the fastened part of the root system in the icicle layer. (d) Main factors which concerns the breaking of the roots caused by the formation of the icicle layer seem as follows: (1) Heaving strength at the time of forming the icicle layer. (2) The resistant power of the plants. (3) The friction between plant and frozen soil. (4) Effects of the development of the root system upon the formation of the icicle layer.

Havaintoja muutamien nurmikasvien kehityksestä kylvökesän aikana

Havaintoja muutamien nurmikasvien kehityksestä kylvökesän aikana

Chromosome Numbers in Nodules and Roots of Red Clover, Common Vetch and Garden Pea

Chromosome Numbers in Nodules and Roots of Red Clover, Common Vetch and Garden Pea

Studies on the winter hardiness of clover. I. Effect of cutting on the carbohydrate reserves in red clover roots

The effect of different cutting practices on the carbohydrate root reserves of Finnish red clover was studied. Cutting causes a rapid decrease in the insoluble sugars. The minimum is reached in about 12–15 days, independently of the time of cutting. However, the initial carbohydrate level is reached much more quickly in autumn than in June-July. The carbohydrate content of the roots in autumn is higher the later the second cut.Cutting does not significantly affect the content of sucrose and other soluble sugars, the values for which are very low during June-August, but rise towards autumn.

UNFREEZABLE AND FREEZABLE WATER EQUILIBRIUM IN PLANT TISSUES AS INFLUENCED BY SUB-ZERO TEMPERATURES

It is commonly accepted that with bioeolloidal systems there is a definite temperature at which all of the freezable water will be frozen (7, 11, 6, and others). This temperature has been arbitrarily selected as about -18° to 20° C. In studying one phase of a problem on winter hardiness in red clover roots, it was desirable to determine the amount of unf reezable water in these tissues. Thus an opportunity was afforded to test the preceding hypothesis with regard to this tissue by determining the amount of water which does not freeze at temperatures of -10° to -50° C. Potato tubers were also included in the study.