Search

Copyright of Weed Research is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A ring-hydroxylated metabolite was produced by excised oat, barley, and corn roots from phenoxy-n-aliphatic acids, acetic through hexanoic, which possessed an even number of carbons in the side chain. Peanut, soybean, and alfalfa roots did not show this activity. Paper chromatographic and ultra-violet spectral data indicated that the metabolite was 4-hydroxyphenoxyacetic acid. There was no evidence for production of hydroxylated products of longer chain length. This suggests ring hydroxylation may have followed β-oxidation of the side chain. The greater hydroxylation activity of the relatively resistant gramineous species as compared to the susceptible legumes is compatible with the suggested role of hydroxylation as a detoxication reaction. [ABSTRACT FROM AUTHOR]

1. A method bas been worked out with phosphate buffer, pH 7.2, for the extraction of auxins and growth inhibitors from maize kernels. 2. The content of free and bound acid auxin in maize kernels is greatest in unripe maize and decreases in connection with the maturation of the kernels. 3. Four different growth stimulators have been found in the acid fraction of ether extracts of maize kernels of different degrees of swelling. On chromatographing in isopropanol-ammonia-water these have the following Rf values: a, 0-0.1; b, 0.2-0.4 (IAA); c, 0.5-0.8 and d. 0.8-1.0. Inhibitors have been detected with the Rf values 0.1, 0.5 and 0.8-1.0. 4. Two growth-stimulating substances, e and f. have been found in the neutral fraction of phosphate buffer extracts. Their Rf values in different solvents have been determined (see Table 4). In chromatographing f forms partly another substance, g, e is easily converted into a mixture of f and g, All three substances exhibit a reaction with Ehrlich s reagent and therefore they all are probably indole compounds. They also react with ninhydrin. Paper chromatography has shown that f is identical with tryptamine (see Figures 9 and 10). e and g have not been identified. f has also been found in ether extracts. 5. e apparently constitutes an intermediary link between IAA and inactive IAA precursors. [ABSTRACT FROM AUTHOR]

Copyright of Weed Research is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The present paper deals with some aspects on the geotropic response of higher plants, on the auxin-induced potentials in Zea Mays and also on connections between these effects which could not a priori he assumed to exist. The main results are summarized in the following: 1. The logarithmic stimulus-response relation is found to regulate geotropical bending of Avena coleoptiles al 22.5° and 10.0°C and with forces in the region 0.2 to 12.5 times the gravitational force. 2. The reciprocity rule is valid for Avena at 22.5°C, while measurements at 10.0°C. do not clearly support this rule. 3. Investigating the geoelectric effects on Zea Mays at different temperatures and forces gave the expected polarity (the "under" side of the coleoptile positive with respect to the "upper"). At all temperatures and with all forces the existence of a latency period is confirmed. It is shown by varying force and temperature that the latency time for Zea Mays may be separated into two parts, one of which has a Q10, indicating a chemical reaction. The second part of the latency time has been used to test the reciprocity rule. This is strongly supported for Zea mays in the force region 0.2-12.5 g at 10.0, 22.5 and 30.0°C. 4. To explain the presentation times two theories are examined the first of which is the ordinary "sedimentation of statoliths" theory, the second based upon Brownian movements. [ABSTRACT FROM AUTHOR]

This article focuses on the paper "Essential Fatty Acids, Degree of Unsaturation and Effect of Corn (Maize) Oil on the Serum-Cholesterol Level in Man," by Ancel Keys, J.J. Anderson and Francisco Grande that was published in a 1957 issue of the periodical "Lancet." Substituting carbohydrate for the common meat can lower the serum cholesterol level in man and dairy fat in the diet and this does not depend on the intake of cholesterol itself. Different fats vary in their effect and certain vegetable oils may depress the serum cholesterol. Corn (maize) oil has been found particularly effective and it has been suggested on the one hand that its effect depends on the degree of unsaturation of the constituent fatty acids, and on the other that it depends on the amount of the essential fatty acid, linoleic acid.

The intra-cellular localization of the herbicide N,N-dimethyl-2,2-diphenylacetamide (diphenamid) was examined in 10 mm root tips of corn seedlings (Zea mays L. cv. Shawnee). Experiments are described which culminate in the observation. that a significant, measurable effect on root growth occurs within 12 hours after treatment with diphenamid. Corn seedlings were then treated with 14-C-diphenamid for 12 hours and the 10 mm root tips excised and homogenized. By use of differential centrifugation and gel filtration, the root homogenate was separated into fractions as follows; cell wall, mitochondria, microsomal, protein and eluate. The highest concentration of the herbicide was found in the root tips. Furthermore, most of the radioactivity was found in the eluate. Results are discussed as to localization of diphenamid in the microsomal and protein fraction and possible mode of action. [ABSTRACT FROM AUTHOR]

A "quasi-diffusion resistance", rq' is defined to accommodate the role which the thermochemical and photochemical phenomena of photosynthesis play in the control of CO2-fixation to the terminology and approach of the diffusion resistance analogue for the CO2 exchange of leaves. The relationship of rq to Rabinowitch's classical rectangular hyperbolic model of photosynthesis rate as a function of CO2-concentration at the carboxylating surface is discussed. Examination of KmnPP for phos- Phopyruvate carboxylase (the predominant carboxylase in maize) suggests, as a reasonable hypothesis for light-saturated maize leaves, that rq may be essentially independent of ambient CO2-concentration up to at least 300 μI/I. A corollary of the hypothesis is that an increase of diffusion resistance, rather than of rq, may account for the observed curvature of the response curves of light-saturated maize leaf photosynthesis to ambient CO2-concentration. An experiment carried out on fieldgrown maize plants, using a well controlled leaf chamber as a nitrous oxide diffusion porometer, gave evidence which strongly supported the hypothesis. [ABSTRACT FROM AUTHOR]

This article reports that the pigment deficiency of albino corn seedlings is due to an extreme light sensitivity of albino tissues. The pigment destruction is an oxidative process. The increased light sensitivity may be explained by the abnormal carotenoid composition of the albino tissues. Studies on the effect of selective enzyme inhibitors on the carotenoid content direct our attention to the probable role of copper enzymes in the synthesis of carotenoids. The activity of cyanide-sensitive enzymes in albino leaves is decreased upon illumination and this might affect the connection between dehydrogenases and the synthesis of leaf pigments.

This paper provides a detailed analysis of bird damage assessments to detect crop loss in corn. Measurement criteria, methods of loss calculation, and rate of sampling are discussed. In planning a strategy to measure crop loss, one needs to take into account distribution of damage as well as variation in measurement.

Stacking of chloroplast lamellae, isolated from normal and carotenoid mutant chloroplasts of maize (Zea mays L.), was determined after a high‐salt treatment. Stacking of isolated lamellae under favourable ionic conditions was almost identical with that occurring in intact chloroplasts; thus, differences in granum content could be attributed to the architectural properties of lamellae. Gaussian analyses, performed on the red band of room temperature absorption spectra, have shown that chloroplasts with lamellae of high stacking capacity contain relatively more Chl a662 than chloroplasts containing lamellae of low stacking capacity. The presence of Chl a705–708 was characteristic of preparations containing considerable amounts of stroma lamellae. [ABSTRACT FROM AUTHOR]

The postulate that single roots of Zea mays transport their absorbed phosphorus nonuniformly to the leaves was tested. Plants were grown under growth chamber conditions for three to four weeks in nutrient solution. At this stage of growth a series of plants was placed into a system in which two roots on each plant were allowed to absorb either 33P or 32P from uptake solutions for time intervals of up to 24 hours. Plants subsequently were harvested such that each leaf was partitioned into samples containing tissue from one side or the other of the midrib. All samples were assayed for 33P and 32P and the results were expressed as the amount of total P transported into different plant parts from a single root. Nonuniform P accumulation in the leaves occurred and different patterns of accumulation, dependent on the type of root chosen for uptake were observed. Nearly uniform P accumulation occurred between one side and the other of a given leaf when transport was from radicle roots. In marked contrast, transport from adventitious roots resulted in an alternating pattern of accumulation between one side and the other of each successive leaf up the stem. The seminal root system supplied more P to the older leaves than did the adventitious root system. The nature of these nonuniform P transport patterns is attributed to the vascular organization between roots and leaves. [ABSTRACT FROM AUTHOR]

Copyright of Weed Research is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Exudation from the xylem of excised maize roots was studied in roots bathed in solutions containing kinetin or abscisic acid (ABA). Kinetin reduced the water permeability of the roots whilst ABA increased it. The action of both hormones was reversible and both were effective at concentrations of 10-6M and below. The possible in vivo role of these two hormones is discussed. [ABSTRACT FROM AUTHOR]

The effect of Endogone infection on the stem anatomy and on the reproduction in tomato, maize, strawberry and petunia was examined. In tomato, petunia and maize plants, the infection increased the amount of vascular tissue. The lignification of the xylem was greater in mycorrhizal tomato and petunia plants and more vascular bundles were produced in the maize plants. Mycorrhizal infection stimulated flower production in petunia, the formation of fruit in strawberry and the development of pollen in maize. [ABSTRACT FROM AUTHOR]

Toxins from Helminthosporium maydis race T and Phyllosticta maydis have been found to affect the functional processes of corn mitochondria isolated from Texas male-sterile (T) cytoplasm, but not of mitochondria Isolated from nonsterile (N) cytoplasm. The effects of chemicals known to induce responses similar to those of the toxin were compared on mitochondria isolated from T and N cytoplasm inbreds (W64A, Zea mays L.). Valinomycin, gramicidin, and decenylsuccinic acid (DSA) each caused more swelling (measured by transmission changes in %) of N mitochondria than of T mitochondria. The stimulation of exogenous NADH oxidation was the same for N and T mitochondria in the valinomycin, DSA, and Ca2+ plus phosphate treatments, was greater for T mitochondria than for N mitochondria in the gramicidin and DNP treatments, and was greater for N mitochondria than for T mitochondria in the Ca+2 minus phosphate treatment. Sodium azide inhibited NADH oxidation equally for N and T mitochondria. In addition, N and T mitochondria had similar respiration rates for various substrates and equal efficiencies of oxidative phosphorylation. In contrast to the specificity of toxins for T mitochondria, none of the treatment effects were specific for N or T mitochondria. The results indicate that mitochondria isolated from N and T cytoplasm generally respond similarly to various conditions, but that there can be quantitative differences in the response. The extent to which these differences represent cytoplasmically controlled modification of mitochondrial physiology or structure is not known. [ABSTRACT FROM AUTHOR]

The effects of juglone on the uptake of O2 by excised corn roots (Zea mays L., Wf9 cms- TxM14) and isolated corn mitochondria are reported. The O2 uptake by excised corn roots, as measured by an O2 electrode, was inhibited more than 90 % after a one-hour treatment of 500 µΜ juglone. Lesser inhibitions were observed with 50 µΜ and 250 µΜ juglone. In a KCl reaction medium in the absence of inorganic phosphate (Pi), juglone stimulated the rate of O2 uptake by isolated mitochondria oxidizing NADH, succinate, or malate + pyruvate. In the presence of Pi, juglone concentrations of 3 µΜ and greater inhibited the state 3 oxidation rates of succinate and malate + pyruvate, lowered respiratory control and ADP/O ratios obtained from the oxidation of NADH, malate + pyruvate, or succinate, and reduced the coupled deposition of calcium phosphate within isolated mitochondria driven by the oxidation of malate + pyruvate. The inhibition of state 3 O2 uptake by isolated mitochondria, an oxidative state in which electron transfer is coupled to ATP production, is seen to correlate with the inhibition affected by juglone when applied to tissues in vivo. [ABSTRACT FROM AUTHOR]

Effects of coumarin on fresh weight, dry matter, protein and nucleic acid content per cell in attached roots of maize and wheat and in whole excised elongation zones of maize were determined. The inhibition in cell length exerted by coumarin did not correspond to an inhibition of the net synthetic capacity. Coumarin treatment increased the cell surface, the production of dry matter and the protein content per cell. The dry matter and the protein content per unit surface was slightly increased or unaffected. The effect of coumarin on cell shape seemed to be independent of that on dry matter production and net protein synthesis. The same was found in excised elongation zones. — The net DNA-synthesis per cell was slightly increased in attached roots by coumarin treatment, but this effect was probably not correlated with the morphogenetic changes. Inhibition of DNA-synthesis with hydroxyurea did not alter the coumarin induced changes in cell shape. — The net RNA-synthesis per cell was slightly decreased after coumarin treatment, but the net RNA-synthesis per cell and the morphogenetic effects exerted by coumarin were not related with each other. Inhibition of m-RNA synthesis with actinomycin D did not prevent the effects of coumarin on cell division, cell expansion, dry matter production and net protein synthesis. The same was true for inhibitors of protein synthesis, puromycin and p-fluorophenylalanine. The findings are in support of the view that coumarin affects already existing structures or enzymes. — Comparisons between coumarin and the uncouplers, DNP and dicoumarol, showed that the effects of coumarin were not, solely, due to uncoupling. SH-protecting agents, BAL, DTE and glutathione, did, with few exceptions, not reduce the morphogenetic effects of coumarin. [ABSTRACT FROM AUTHOR]

The effect of coumarin, IAA, ethylene, kinetin and gibberellic acid on roots of maize and wheat was investigated. Sterile attached and detached roots and isolated elongation zones were used. In some experiments a semi-sterile procedure was followed. The effects of the different regulators separately or in various combinations together with coumarin were studied on the root growth with regard to division, elongation and swelling of the cells, The ethylene production in isolated elongation zones was measured after treatment with coumarin, IAA, PCIB, kinetin, colchicine and dinitrophenol. The results show the following: 1) Each substance produces a specific morphologic pattern. 2) Changes in polarity were demonstrated for auxin-induced swelling in cell divisions and cell expansion and for coumarin-induced swelling in cell division. Other cell expansion in swollen parts was due to cylindric cells increasing in width while retaining their cylindric form. 3) Coumarin-induced inhibition could not be counteracted by IAA, PCIB, carbon dioxide, kinetin, gibberellic acid or Cycocel. 4) The ethylene production in isolated elongation zones increases noticeably after kinetin treatment, less strongly after auxin treatment and least after coumarin treatment. The production of ethylene does not seem to be correlated with the morphogenetic effect of the different substances. 5) The isolated elongation zones reacted to a) IAA and kinetin with an increase in length in some cases and b) gibberellic acid with a reduction of their width. 6) The inhibitory effect of coumarin on the growth in length of the elongation zones was diminished by kinetin. The swelling produced by coumarin in these zones was reduced by gibberellin acid. The effects just mentioned of kinetin and gibberellic acid. The effects just mentioned of kinetin and gibberellic acid were considered as indirect ones. — From the present finding it was concluding that concomitant effects of auxin, ethylene, cytokinins and gibberellins are not obligatory are not obligatory for coumarin to exert its morphogenetic effects on root growth. In discussing the results some pitfalls in studies of growth reactions after application of hormones to roots containing meristem were emphasized. [ABSTRACT FROM AUTHOR]

Xylem sap was collected from nitrogen-starved maize plants and investigations were made on the nitrogen transported. It appears from the results that several pools for different amino acids exist, which have different relations to the transport of nitrogen taken up. While in maize roots Glu, Glu-NH2 and Arg are transported directly from the place of their synthesis, the transported Asp and Ala predominantly derive from the pool of amino acids synthetized before application of nitrogen. An explanation of this observation is offered. [ABSTRACT FROM AUTHOR]

Mitochondrial complementation (enhancement of oxidative activity of mitochondria) occurred when mitochondria of some inbreds of corn were mixed in vitro. It was found that mixtures composed of various proportions of mitochondria of inbreds exhibited complementation. Extracts of mitochondria of one inbred did not promote complementation when they were added lo intact mitochondria of the second inbred. Serial dilutions of mixtures resulted in a rapid reduction of mitochondrial oxidation (Qo2, N) suggesting that intimate association between mitochondria was minimized by the dilution and that this decreased complementation. Similar dilutions of mitochondria from inbreds did not decrease their specific activity. Kinetics of mitochondrial oxidation were measured polarographically and it was found that complementation was measurable immediately (1 min) following the mixing. This suggested that physical contact between mitochondria was necessary for complementation. [ABSTRACT FROM AUTHOR]

Red light effects on the uptake of 14C and of 32P was studied by observing leaf sections from 8-day-old etiolated coin leaves that were placed on various substrates following a brief exposure to red radiant energy. There was a general increase of 14C uptake over dark levels into all metabolite fractions that were prepared. This is in contrast with results obtained previously in which leaf samples were first floated on substrate and then irradiated (Mitrakos et al. 1967, Price et al. 1965). The latter tests resulted in a general decrease in sugar and starch as well as 14C content of all fractions. However, under both types of experimental conditions the red light effect manifested itself as an increase in hexosemonophosphate turnover rate and accumulation of radioactivity in the cell wall polysaccharide fraction. The present data further substantiate the previous work in that they demonstrate the regulatory influence of the hexose pool size on the intermediary metabolism and the manifestation of the phytochrome responses. From the data thus far obtained it cannot be determined as to whether or not phytochrome mediates by controlling phosphorylating activity or through control of specific enzymatic processes that lead to observable cell wall polysaccharide synthesis and leaf unrolling. [ABSTRACT FROM AUTHOR]

Corn seeds were treated with 0.01 M sodium fluoride for various time periods. The treated seeds were germinated and grown until the seedling roots reached a standard size of 12 ±3 mm. Analyses were made for RNA and DNA contents of 3-mm seedling root tips. Determinations also were made for growth rate, rate of cell elongation, cell multiplication, and tissue maturity of 12-mm roots. RNA contents of 3-mm root tips were found to be directly proportional to the growth rates of the entire seedling root of corn seeds treated with sodium fluoride for various periods of time. The RNA content was reduced on a cell basis and was independent of the root tip cell number. The amount of DNA was not related to the growth rate of the intact seedling roots. Since fluoride reduced the number of mitotic figures, it was likely that fluoride inhibited DNA synthesis during the interphase of the mitotic cycle. Growth by cell multiplication was inhibited more than that by cell elongation in the sample treated with fluoride for a scorter period. The two types of growth, however, showed a similar level of growth reduction in the sample treated with fluoride for a longer period. Fluoride seemed to reduce the rates of cellular elongation and multiplication not more than about 40 per cent of the control value in these tissues under present experimental conditions. Fluoride also induced maturity in the seedling roots in proportion to the periods of fluoride treatment. [ABSTRACT FROM AUTHOR]

Mitochondria isolated from inbred and hybrid maize scutella were found to exhibit enhanced oxidative and phosphorylative activity in many cases when treated with physiological concentrations of IAA. It was found that the genotype being tested, the substrate utilized, and the concentration of IAA applied had significant effects on the degree of enhancement or inhibition observed in each case. These results suggests that IAA is related in some manner to the activity of the respiratory enzymes of the mitochondria. [ABSTRACT FROM AUTHOR]

Homogenization of maize root tips in buffered sucrose containing ethylenediamine-tetraacetic acid produces a smaller mitochondrial fraction than does homogenization in sucrose alone. If the maize seedlings are grown in the presence of calcium the homogenates produce a slightly larger mitochondrial fraction with both isolation media. It is considered that isolation with EDTA produces a cleaner mitochondria fraction; with such isolation it appears that the yield of mitochondria is about 10-15% greater from roots grown with adequate calcium. The results of Florell and Lindblad on yield of mitochondria from wheat roots are discussed. [ABSTRACT FROM AUTHOR]

Corn plants treated with 3-amino-1,2,4-triazole produced chlorotic tissue which had a respiratory quotient near 0.80. Chlorotic tissue contained increased concentrations of manganese, free ammonia, total nitrogen, and generally total carbohydrates. Protein content of chlorotic tissue was usually reduced whereas free amino acids were increased; concentrations of these two components and of free ammonia was influenced by duration of light. Herbicide toxicity was increased as a result of ammonia fertilization as compared to nitrate fertilization whether the herbicide was applied to the roots or the leaves. Gaseous ammonia also increased herbicide toxicity. [ABSTRACT FROM AUTHOR]

Corn plants treated with 3-amino-1,2,4-triazole produced chlorotic tissue which had a respiratory quotient of 0.82. Seeds attached to these plants had greater fat content and a more active lipoxidase system than did untreated plants. Untreated plants had approximately 50 percent less total carhohydrates but twice the aldolase activity of treated plants. Sodium fluoride caused essentially the same amount of inhibition in both tissues but iodoacetate and malonic acid gave far greater inhibition in chlorotic tissue than in untreated tissue. It was postulated that chlorotic plants were metabolizing fats as a major respiratory substrate while untreated plants were metabolizing carbohydrates. [ABSTRACT FROM AUTHOR]

Discusses the partnership of Edgar Corrie, John Gladstone and Jackson Bradshaw during the regional corn deficit in South Lancashire, England. Industrialisation in the last decades of the eighteenth century; Why cereal agriculture diminished; Implications of the corn problem for South Lancashire; Issue of preserving standards among dealers; Corn-trading connections; Growing market potential; Approach of Edgar Corrie, Gladstone and Bradshaw to corn marketing; Corrie's plan for a major speculation in American grain; Success of the firm.

Copyright of Weed Research is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Weed Research is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Weed Research is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Weed Research is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Weed Research is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Weed Research is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Weed Research is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Weed Research is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Weed Research is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The study undertaken shows the existence of water-soluble complexes of sterols, sterol esters and their precursors (triterpenes and 4α-methylsterols) in a higher plant, Zea mays L. The leaves, roots and culture medium were treated separately in order to investigate the role and nature of these complexes. The sterols found in the water-soluble form represent 0.1-1% by weight of the total sterols in the plant. The composition of the hydrosoluble fraction of the sterols and their precursors is different from that of the lipid-soluble fraction, cholesterol, sitosterol and isofucosterol being preferentially complexed compared to campesterol and stigmasterol. This complex was found in the microsomal supernatant after homogenisation and also in the culture medium. The sterols are released from the complex by a treatment with pyrogallol under basic conditions or after repeated extraction with petroleum ether. The complex is precipitated with ethanol but not with trichloroacetic acid. The behaviour of several sterols on treatment with a solution of starch was investigated. Starch was able to complex with a large number of phytosterols unspecifically. The implication of this complex for the transport of sterols, for the biosynthesis of steroids and the ecological impact is discussed. [ABSTRACT FROM AUTHOR]

The article presents an experiment which examines the significance of light rainfall to the survival of plants, particularly maize, in East Africa. Maize, a type of corn, is an annual field crop across the region. It explores the water distribution of the plant's root system during dry seasons. Findings reveal that the amount of water available to the plant from each shower depends on the water holding capacity of the soil. It states that the plant's surface, which will be exposed to the rain, varies to its canopy structure.

The article presents a study on the influence of the environment on seed and seedling mortality. It involves two experiments which were done in 1955 and 1956 at the Oxford University Field Station in Wytham with the use of the soil derived from Oxford clay that overlies Thames gravel. Rhodesian White Horsetooth maize was used in both experiments which had been treated using dry seed dressing of a commercial preparation of tetramethyl thiuram disulphide (TMTD). It was found out that both date of sowing and colour of the soil produced highly significant effects but their interaction was not significant.

The article looks into the influence of environment and seedling mortality of maize. Five different varieties of maize was sown at weekly intervals on pyramids soils with slopes at 22.5°, 11.25° and 6.25°. A comparison was made with sowings on horizontal ground in relation to ultimate emergence and the time consumed for 50 per cent emergence. The study revealed that a close relationship occured between soil temperature and the time elapsed from sowing to 50 per cent emergence of maize, in which the latter is inversely correlated with the ultimate emergence of maize. Among the five varitiesm Baanbreker recorded the highest emergence from all sowing dates.

Endotrophic mycorrhiza in tomato and maize, induced by chlamydosporic varieties of Endogone macrocarpa, were examined quantitatively by estimating infection of roots, pigmentation of roots and production of ectocarpic chlamydospores. When the size of the root system was taken into account, estimates of infection showed a relationship to growth of the host. The amount of pigmentation within the root system gave a good indication of mycorrhizal intensity and was related to the size of the host at high levels of infection. The numbers of spores produced on an individual root system, given a particular treatment, were positively correlated with the size of the host. The relative merits of these different assessments of mycorrhiza are discussed. [ABSTRACT FROM AUTHOR]

Although no cell division was detected in the radicle during the first 24 hours of imbibition by the caryopses of Zea mays, fine structural changes showed the re-establishment of a developmental pattern during this period. Such changes included mitochondrial differentiation, the appearance of dictyosomes and a complex system of ER, and the association of ribosomes to form polysome-like structures. Association between ER and lysosome-like bodies was seen during this stage, together with an intensification of the acid phosphatase reaction within the lysosomes. By the 48-hour stage, easily-separated, senescent cells had been produced and cell division had begun. Vesicles produced by the hypersecretory activity of the dictyosomes were either incorporated into the developing lysosomes or passed through the cell membrane to the wall. In the outermost cells the lysosomes finally ruptured and acid phosphatase activity became detectable in the ground cytoplasm. The development of the lysosomes and the hypersecretory activity of the dictyosomes are discussed as evidence of constructive changes implying genetic control of cellular senescence in the root cap. [ABSTRACT FROM AUTHOR]

This article is concerned with a description of a series of cultural characteristics associated with four strata of the social structure in a Middle Western community of some 10,000 population, which the author shall hereafter call "Elmtown." Elmtown is an all white community located near the center of the corn belt on a rich glaciated plain bisected by a navigable river. Its highly mechanized agricultural activities are integrated around corn and hogs, with the production of small grains and soy beans as secondary crops. Coal mines and three large factories give the community an industrial as well as an agricultural base. Elmtown's social structure is composed of five strata whose members understand with varying degrees of precision how each ranks in the hierarchical order. Assignment to a given stratum or class within the social structure appears to be dependent upon the possession and expression of a constellation of culture traits that are evaluated by the members of the community as appropriate to that particular stratum.

The article focuses on the corn and hog industry which is one of the most fundamental enterprises in the U.S. Corn is the most important crop in the U.S. both in acreage and value. More than three-fourths of the farms included by the 1920 census reported corn. The value of corn has been greater than the combined values of wheat and cotton during nine of the eleven years from 1910 to 1921. The farm value of hogs produced for slaughter has been second to the value of corn in every year from 1910 to 1921. The Corn Belt farmer has a choice of marketing his corn direct to the primary markets as cash grain, or of marketing it through livestock. The outstanding use of corn is as a feed for animals. More than 85% is given to horses, 4% to poultry, 1% to sheep, 5.5% to stock not on farms, 1.5% is exported and 3% for other uses. The price of corn at a given time depends primarily upon the supply and supply is determined principally by the weather. The demand for corn for export and commercial uses is relatively small compared with the demand for corn as feed for livestock. The prices of the corn over a period of years depends largely upon corn production. The demand for corn is relatively inelastic.

Several serum fractions containing the seventh component of complement have the capacity of liberating fatty acids from a tributyrin substrate. Reagent H (gp) is depleted of its tributyrinase content after it has reacted with an EAC142 intermediate and so had the possibility of completing the formation of an EAC1-7 intermediate. The enzyme content of reagent H remains unchanged after contact of H with EA cells. EAC1-7 intermediates prepared by five different techniques with various sources of C7, when submitted to Weiner's elution method liberate a tributyrinase. This has never been found in eluates made from intermediates prior to the EAC1-7 stage, that is from EACH through EAC1-6. It is concluded that an enzyme shown to have the properties of a tributyrinase is responsible for the activity of haemolytic C7. [ABSTRACT FROM AUTHOR]

Reports on a study conducted to find the effect of crop and climatic factors on the radiation balance of an irrigated maize crop. Site where the experiment was conducted; Methods of measurement used in the study; Factors that affected the accuracy of measurements in the experiment; Significance of radiation balance for evaporation and photosynthesis by the maize crop.

Describes a study which provides information on the assessment of the value of dilute dust insecticides for the protection of stored maize in Kenya. Description of materials and methods used in the study; Highlights of experimental results obtained during the study; Discussion on the economics of application of the best insecticide on a large scale.

A new and pleomorphic species of Chlorosarcinoopsis from a Connecticut crornfield soil is described. Two populations were observed and cultured. One produced mostly smoth colonies on agar and formed few packets; the second produced large percentages of rough colonies on agar and frequently formed packets. In older agar cultures numerous Hormotilalike colonies can be observed in both strains. [ABSTRACT FROM AUTHOR]

This article investigates regional variations in the abandonment of arable land in the early fourteenth century, first within England as a whole and secondly within three counties in particular. The Nonarum Inquisitiones relate to a grant by Parliament to King Edward III in 1342, to assist him in his wars, of one-ninth of the value of corn, wool and lambs produced in the realm. The value of these items was assessed, parish by parish, from the evidence given by groups of parishioners under oath. The inquiries were conducted in the early months of 1342 but related to agricultural production during 1341. Although the Record Commission published a transcription of the Nonarum Inquisitiones as long ago as 1807 this body of evidence has not been fully employed. It has, however, been distinctively used by researchers R.A. Pelham and E.M. Yates. In 1931 Pelham produced a map showing the 1341 valuations of corn, wool and lambs in each Sussex settlement, which demonstrated the overwhelming predominance of corn-growing even among settlements in the Chalk zone, long regarded as primarily a sheep-raising region.