Young Corn Plants Research Articles

Growth Rate‐Nutrient Concentration Relationships During Early Growth of Corn as Affected by Applied N, P, and K

AbstractThree greenhouse pot experiments with corn (Zea mays L.) were conducted to study effects of multiple rates of applied N, P, and K on growth and yield—nutrient concentration trends. Harvests were made each 4 or 6 days from 15 to 56 days after plant emergence. Growth and plant nutrient concentrations and uptake increased with rate of each applied nutrient at adequate levels of other nutrients. Applied N also increased both P concentrations and uptake in young corn plants. Yield response to applied K resulted only in dilution of N and P concentrations at even the earliest harvest. Concentrations of all nutrients were soon diluted to lower levels with increase in dry matter and/or age of plants, so that comparative results varied with time of harvest. Growth rates increased with adequacy of nutrient supply and more favorable growth conditions; they declined greatly soon after depletion of applied N. The limited soil volume in pot experiments, rate of growth, and time of harvest all greatly influence the effects of one nutrient on plant concentrations of other nutrients.

Effect of lead and cadmium upon the boron, copper, manganese, and zinc concentration of young corn plants

Abstract In a greenhouse experiment corn plants were harvested 24 and 31 days following emergence from pots containing Bloomfield loamy sand (Psammentic Haplaudalf). Soil P was 140 kg/ha, exchangeable K was 220 kg/ha, and soil pH was 6.0. The soil CEC was 2.3 meq/100 g. Boron, Cu, Mn, and Zn were determined with emission spectroscopy. Treatment combinations were a factorial arrangement of 0, 2.5, and 5 μg/g of Cd and 0, 125, and 250 μg/g of Pb. Main effects of Cd and Pb significantly affected the B concentration of corn plants 24 days following emergence, and specific main effects (linear and/or quadratic) influenced the concentration of other nutrients. At the later stage of development (31 days following emergence), neither Cd nor Pb affected B concentration in corn plants, and there was only one significant (α = 0.05) main effect influencing the nutrient status of other micro‐nutrients studied. However, several Cd‐Pb interactions affected micronutrient concentration in corn plants. Our results suggest that the effect of Cd or Pb upon the nutritional status of corn depends upon stage of development of the plant as well as the Cd or Pb rate.

EXTRACTABLE PHOSPHORUS IN SURFACE AND SUBSURFACE LAYERS OF STE. ROSALIE AND ST. BLAISE SOIL SERIES IN QUEBEC

The relationship between extractable P and soil characteristics including pH, clay content (CLAY), cation exchange capacity (CEC), organic matter content (OM), and phosphorus retention (PRET) was determined using stepwise multiple regression analysis. Similarly, the influence of pH, CLAY, CEC, OM and PRET on the relationship between extractable P and relative yield (Yo/Yp) of young corn plants in the greenhouse was determined. Surface (0- to 20-cm) and subsurface (20- to 40-cm) layers from two soil series (St. Blaise and Ste. Rosalie) were collected from farm fields in the region south of Montreal. Twenty-eight sites of the St. Blaise series and 25 sites of the Ste. Rosalie series were sampled from fields of which the majority were in cultivation for 100–200 yr. Three P extractants were used: Bray 1 (P1) (0.03 N NH4F, 0.025 N HCl), Bray 2 (P2) (0.03 N NH4F, 0.1 N HCl) and 0.5 M NaHCO3 (P3). Extractable P by all three extractants was negatively correlated with pH of the St. Blaise surface soils. However, extractable P by the P2 extractant was positively correlated with pH of the Ste. Rosalie surface soils. Although significant, the R2 values for these relationships were low, ranging from 0.15 to 0.17 for the surface soils. Extractable P was related, to variable extents, to one or more of pH, PRET, OM and CEC of the subsurface soils depending on the soil series and P extractant in an unexplainable manner. However, the R2 values were generally much higher for the subsurface than surface soils suggesting that extractable P in subsurface soils was more closely related to the measured soil characteristics. There was no relationship between extractable P with any extractant and CLAY for either series. The highest correlation between relative yield (Yo/Yp) and extractable P occurred with P3 for the surface soils of both series. None of the soil characteristics was included with P3 in the regressions with the surface soils. PRET was included along with P2 in the regression with Yo/Yp for the St. Blaise surface soils, whereas a P × CLAY interaction term occurred with the P1 and P2 extractants for the Ste. Rosalie surface soils. A linear relationship was obtained between Yo/Yp and P1 or P3 for the Ste. Rosalie surface soils and P2 for the St. Blaise surface soils. A curvilinear relationship was obtained with P1 or P3 for the St. Blaise surface soils and with P2 for the Ste. Rosalie surface soils. Extractable P was not included as an independent variable in any of the regressions with Yo/Yp as the dependent variable for the subsurface soils. This suggests that extractable P with any of the extractants used in this study does not reflect the availability of P in subsurface soils.

Effects of sulfur deficiency on non-protein nitrogen, soluble sugars, and N/S ratios in young corn (Zea mays L.) plants

The concentrations of several N fractions, soluble sugars and N/S ratios were determined in Golden Bantam sweet corn and hybrid field corn grown in nutrient solutions and/or soil with various SO4-S levels provided. When the level of SO4-S supplied was less than that needed for maximum growth, higher-than-normal concentrations of amide (asparagine) N and lower-than-normal soluble sugar concentrations were found in the plants. An inadequate S supply appears to limit the plants capacity to synthesize protein to a much greater extent than it inhibits the nitrogen uptake mechanism.

Absorption, excretion and tissue distribution of natural organic and inorganic zinc-65 in the rat.

The absorption and tissue distribution of organic and inorganic forms of 65-Zn were studied in the rat following single tracer oral doses. Rats dosed with 65-Zn grown into young corn and rye plants (organic form) absorbed and retained more 65-Zn in tissues than those given 65-Zn mixed with tissue paper (inorganic forms). A part of the beneficial effect was evident when 65-Zn was mixed with forage. The relatively high absorption values indicate that both forms were readily available, and thus incorporating zinc into young forage protein is not of major practical importance.

Degradation of 4-aminopyridine-14C in corn and sorghum plants.

Acetone-soluble radiolabeled metabolites, a; determined by thin-laver chromatographic procedures, were not detected in roots and shoots of young corn plants (Zea mays) culturcvl 7 days in nutrient solutions containing 10 ppm of 4-aminopyridine- C...

Relation Between Nitrate Absorption and Water Transpiration by Corn

AbstractThe relationship between the absorption of NO3‐N by young corn plants (Zea mays L.) and the quantity of water transpired was studied in solution and soil culture. Tracer N (15N) was employed to measure NO3 absorption. Gravimetric methods were used to monitor evapotranspiration. From solution culture, NO3 was absorbed at rates relatively greater than water. From soil culture, NO3 was absorbed at a relative rate close to that of water when the soil was not pretreated. However, when the soil material was wetted and leached of soluble N before planting corn, NO3 was absorbed at a relative rate 1.5 to 2.0 times that of water. In soil situations where water was not being absorbed by plants, NO3‐N likewise was not absorbed. Mass flow and diffusion both were involved in NO3 transport to roots. Prior cultural conditions had a marked influence on active uptake of NO3 presumably through an influence on specific rates of N absorption.

Dry Matter Yield—N and S Concentration Relationships and Ratios in Young Corn Plants1

AbstractDry matter‐N and S concentration relationships and N/S ratios were studied in corn (Zea mays L.) grown in several greenhouse pot experiments on soil deficient in both N and S for good growth. Such relationships and ratios are basic to the proper interpretation of plant analysis results. Minimum concentrations in the dry forage necessary for continued growth of corn at 6 to 8 weeks were about 0.70% N and 0.045% S. Total N/S ratios varied widely from this ratio of 16, depending on age of plant, excess of N or S necessary for growth, and as a result of dilution of one nutrient by growth response to the other. This value of 16 at the minimum N and S concentrations approximates the ratio in plant proteins. Variations from the ratio of 16 indicate varying amounts of labile, nonprotein N or S.

Rapid determination of nitrate‐n in corn leaves and sugar beet petioles as an indicator of side dressing nitrogen need

Abstract Young corn (Zea mays L.) and sugar beet (Beta vulgaris L.) plants were sampled in plots fertilized with different types and rates of nitrogen fertilizer during the period 1969–72. The twenty six trial fields covered a dozen different types of soil from the Montreal to the lower St. Lawrence River regions. As revealed by nitrate analysis (NO3‐N) there was a marked positive correlation between crop yield, and nitrate nitrogen from the fifth to the seventh week for corn and from the seventh to the eight week for sugar beet. Sampling prior to this was not indicative. A negative correlation was found between NO3‐N and total sugar yield for sugar beet, before the seventh week. Regression analysis, including soil NO3‐N test, showed a positive soil participation from the seventh week for corn and from the fourth week for sugar beet. The critical concentration value suggested for corn, under very adverse climatic conditions, is not less than 150–200 ppm NO3‐N. As a rule, however, the 2,000 ppm value appea...

Relationships Between Dry Matter Yields and Concentrations of Zn and P in Young Corn Plants1

AbstractYield‐Zn or P concentration relationships were studied in corn (Zea mays L.) grown in several greenhouse pot experiments conducted to compare various rates and sources of Zn and P on soils deficient in these nutrients, Such relationships are important in proper interpretation of plant analysis results. The usual result was for corn forage yields to increase at a minimum Zn concentration of 7 to 9 ppm in the dry forage until P or other growth factor became limiting. Then yields leveled off and Zn concentrations increased at sufficiently high levels of applied Zn. Similarly, yields increased at a minimum P concentration near 0.10% until Zn or other growth factor became limiting; P concentrations then increased. Critical concentrations in the dry corn forage were estimated to be about 14 ppm of Zn and 0.14% P.

Concentrations of N and P in Young Corn Plants, as Affected by Various Growth‐limiting Factors1

AbstractYields and concentrations of N and P were studied in young corn (Zea mays L.) plants as a basis for correct interpretation of plant analysis results. The corn was grown on soils deficient in these nutrients in several greenhouse pot experiments comparing rate, source, and placement of N or P. Results from such pot experiments were satisfactory for establishing minimum and critical nutrient concentrations in corn if various growth‐limiting factors were properly corrected. These included age of plant, application rates of one or more deficient nutrients, and adequacy of other yield‐limiting factors, including liming and other nutrients.The minimum concentrations of total N or of P in corn forage appear to be rather constant for a given age of plant and can be more accurately estimated than critical concentrations can. The results suggest the estimation of critical values from the minimum concentrations.C‐type curves resulting from plots of dry matter yield vs nutrient concentration could be explained largely by dilution resulting from growth response to application of a second deficient nutrient.

Fall Armyworm, Spodoptera frugiperda, Males Captured at Three Florida Locations in Traps Baited with Virgin Females

The fall armyworm, Spodoptera frugiperda (J. E. Smith), was captured in traps baited with virgin females before larvae or eggs were observed on corn plants in Belle Glade, Sanford, and Gainesville, Florida. Adult fall armyworms were active in Belle Glade and Sanford prior to or during mid-March. Adult population peaks were not indicated by traps nearly as well as by observation of larvae in the whorl of young corn plants.

Effects of Thermal Exposure on the Foliage of Young Corn and Soybean Plants

Effects of Thermal Exposure on the Foliage of Young Corn and Soybean Plants

The translocation of photosynthetically assimilated 14C in corn

A detailed study was made of translocation of photosynthetically assimilated 14C in 3- to 6-week-old corn plants. Corn assimilated 14C via malate and aspartate, and incorporated most of the 14C into sucrose, the only translocation compound. Lowering the temperature from 26° to 8 °C delayed the incorporation of 14C into sucrose, but had no effect on the distribution of 14C among the intermediates. Recent 14C assimilate was translocated very rapidly from the fed area, the amount remaining in the fed area decreasing logarithmically with time. The translocate moved down the vascular bundle it entered in the fed area, with no detectable lateral movement. The logarithmic profile in the leaf blade appeared to be the result of a temporary accumulation of the labelled pulse in the separate vascular bundles. This accumulation of sucrose in the veins could be eliminated by cutting out the fed area. Between 80 and 90% of the assimilated 14C was translocated from the fed area of the leaf in 24 hours with 50% moved out in the first 30 minutes. Both the rate of translocation and the total amount moved out of the fed area increased as the temperature was changed over the range 7 to 26 °C. Each leaf of young corn plants both imported assimilates from and exported assimilates to all other parts of the plant.

Effect of Changes in Root Zone Temperature on the Subsequent Growth and Development of Young Corn Plants1

AbstractCorn plants were grown to defined stages of shoot development in sand culture at root zone temperatures of 15, 20, and 25C from emergence. Some plants were grown at constant root zone temperatures and others were transferred to the other two root zone temperatures at the 2‐leaf and 4‐leaf stages and then grown to the 4‐leaf and 6‐leaf stages, respectively.The dry weights of the shoots and roots decreased with increasing root zone temperatures at similar leaf stages. Although relative growth rates and absolute growth rates were generally correlated, the latter were chosen on a rational basis to indicate the effects of root zone temperature changes on the rate of dry matter accumulation. The rate of morphological development of the plants increased substantially with increasing root zone temperatures. On the other hand, absolute growth rates of both the shoots and roots tended to be greatest at 20 and lowest at 25C. The optimum root zone temperature apparently decreased for shoot growth but increased for root growth during the 2‐leaf to 6‐leaf stage interval. The previous root zone temperature had a variable influence on subsequent growth for all three temperatures. This effect was difficult to explain but depended somewhat on the corn variety.

Trends in Nitrate Reduction and Nitrogen Fractions in Young Corn (Zea mays L.) Plants During Heat and Moisture Stress1

Trends in Nitrate Reduction and Nitrogen Fractions in Young Corn (<i>Zea mays</i> L.) Plants During Heat and Moisture Stress¹

Factors Influencing the Availability of Sulfur Fertilizers to Alfalfa and Corn

AbstractField and greenhouse experiments indicated that 8‐mesh elemental S was frequently inferior to sulfate forms of S for alfalfa and corn production on S deficient, acid, sandy soils in Nebraska. There was a marked increase in utilization of S from the elemental form during the second year compared with the first year after application.Sulfur flour mixed with the soil was as effective as gypsum either mixed with the soil or side‐banded at planting time for supplying S to young corn plants in the greenhouse. A sidebanded application of the S at planting time was much less effective than the same material mixed with the soil unless a small amount of CaCO3 was also applied in the band. Sulfur utilization by young corn plants was linearly related to approximate specific surface of S particles obtained from 8‐mesh material. The smallest particles, &lt; 0.05 mm. in diameter, were slightly less effective than either S flour or gypsum applied at the same rate. The largest particles, 2.0 to 1.0 mm. in diameter, were relatively ineffective even at high rates of application. Superiority of S flour over 8‐mesh material, at least under some conditions, appears to be associated largely with relative sizes of particles in the two materials.

The Influence of Root Zone Temperature on the Growth and Contents of Phosphorus and Anthocyanin of Corn

AbstractIn a greenhouse experiment corn plants were grown in sand cultures using a complete nutrient solution in which only the P level varied. Root zone temperatures of 15°, 20°, and 25°C. were used in this experiment. In addition, 2 weeks after emergence, a number of plants were subjected to a sudden change in root zone temperature. The dry weight yield and the P content of the tops and the roots and the anthocyanin content of the tops were determined at 2 and 3 weeks.Low root zone temperature severely restricted the growth of young corn plants. High P levels never fully counteracted this harmful effect. It was likely that reduced P uptake at low root zone temperature was caused primarily by a depression in root growth, induced by the low root zone temperature. Anthocyanin synthesis was stimulated by both a low root zone temperature and a low P level in the nutrient solution indicating that purpling of corn is not necessarily an indication of P deficiency.

An Improved Nutrient Culture Technique for Growing Corn under Greenhouse Conditions1

SynopsisA nutrient culture technique has been devised for the production of vigorous healthy young corn plants under greenhouse conditions. The major innovation is the use of Amberlite IRC‐50 resin to buffer the nutrient media in the pH range 4.2 to 4.8. In this range, ferrous iron can be maintained in the media and phosphate concentrations raised to levels (0.5 mM. or higher) adequate for maximum growth, without inducing chlorosis.

Ricerche sulla flsiologia della produzione di tossine in colture diHelminthospobium maydisNishik. et Miy

Abstract STUDIES ON THE PHYSIOLOGY OF TOXIN PRODUCTION BY HELMINTHO-SPORIUM MAYDIS NISHIK. ET MIY. CULTURES. — Helminthosporium maydis produces under artificial culture toxic metabolites, which are responsible of a reduction of wheat and corn rootlets growth, severe alterations in tomato shoots and young corn plants, and growth inhibition of some microrganisms. Cultural conditions for growth and toxin production were studied. Different strains of the fungus vary in their ability of toxin production, the highest amounts being produced by each strain by somewhat different conditions. At least one toxic metabolite can be extracted by chloroform from the cultural filtrates, but probably more than one toxin is produced, and of them at least one is not extracted with organic solvents. Toxic substances can be extracted from the mycelia, but it is not yet possible identify the toxins obtained by the extraction of the mycelia with one or more of the toxic metabolites obtained by extraction of the cultural filtrates.