Levels In Leaf Tissue Research Articles

Manganese Deficiency and Toxicity Effects on Photosynthesis, Chlorophyll, and Transpiration in Wheat1

Wheat (Triticum aestivum L.) production areas are expanding to soils low in available Mn in southern Georgia and to soils high in available Mn in northern Georgia. Useful data on Mn deficient and toxic levels in leaf tissue for top growth and physiological processes in wheat are needed to evaluate growth processes limiting wheat production. The objectives of this study were to correlate Mn deficiency and toxicity levels with top dry weight production, photosynthesis, chlorophyll concentration, and transpiration. Wheat plants were grown in 10 experimental concentrations ranging from 0.09 μM to 9.1 mM in nutrient solution. Photosynthesis and transpriration measurements were made on blade 1 of plants grown in the greanhouse. Total chlorophyll and Mn concentrations were determined on the experimental tissue after freeze‐drying. Foliar dry weights on a per pot (15 plants) basis were also determined. Severe Mn deficiency depressed top dry weight, photosynthesis, and total chlorophyll concentration, but transpiration was unaffected. Mild Mn toxicity reduced top dry weight but not photosynthesis, total chlorophyll concentration, or transpiration. Critical Mn deficiency levels for reducing top dry weight and apparent photosynthesis rates were similar, namely 0.23 and 0.30 mmol kg−1, repectively. Growth reduction from Mn deficiency is possibly due to reduced photosynthesis. Minimum Mn requirements for chlorophyll (0.14 mmol kg−1) is about one‐half of that for top production. The critical Mn deficiency level for transpiration could not be determined. The critical Mn toxicity level for top dry weight occurred at 7 mmol kg−1. Concentrations of 19, 19, and 24 mmol kg−1 were required for the depression of photosynthesis, total chlorophyll concentration, and transpiration, respectively. Maximum growth and yield are expected when the range of Mn concentration in blade 1 is 0.23 to 7 mmol kg−1. The critical levels are prelimilinary values to be used in evaluating Mn status of field‐grown wheat for possible deficiency and toxicity.

The Association of Brome Mosaic Virus and Wheat Rusts: I. Transmission of BMV by Uredospores of Wheat Stem and Leaf Rust

AbstractBoth the stem and leaf rust fungi of wheat (Puccinia graminis f. sp. tritici, P. recondita f. sp. tritici) were investigated as potential vectors of brome mosaic virus (BMV), a pathogen of Gramineae. They were found to transmit BMV to healthy plants through uredospore transfer from hosts infected with both the viral and fungal pathogens. Virus was transmitted even to rust‐resistant and non‐susceptible hosts. Rust‐transmitted virus produced atypical symptoms on plants, could not be extracted by normal low pH methods, and multiplied only to low levels in leaf tissue. Extracted virus was shown to be similar to BMV‐type strain (ATC) by serology, density gradient centrifugation and immunospecific electron microscopy. The importance of the association of BMV with the rust fungus in natural infections is discussed.

Biogeochemical expression of a classic dispersal train of metalliferous till near Hopetown, Ontario

Picea mariana (black spruce), Abies balsamea (balsam fir), Juniperus communus (juniper), Acer saccharum (sugar maple), Populus tremuloides (aspen), grasses, and their till substrate were sampled at a site of zinc mineralization in marble of the Grenville Province of southeastern Ontario. A classic dispersal train derived from the mineralization is defined by the distribution of mineralized boulders and by the areal extent of till that is enriched in zinc and cadmium; it is 70–200 m wide and at least 400 m long.The spatial distributions of zinc levels in leaf tissue of P. mariana, A. Balsamea, and grasses are also effective maps of the dispersal train. This results from strong relationships between plant metal levels and till metal levels across the full range of till metal levels. Metal levels in tree rings show a persistent decrease from older to younger wood.

INTERACTION OF PHOTOPERIOD AND VESICULAR‐ARBUSCULAR MYCORRHIZAE ON GROWTH AND METABOLISM OF SWEET ORANGE

SummaryVesicular‐arbuscular (VA) mycorrhizal infection and growth of Citrus sinensis were increased by longer photoperiods. Photosynthesis and stomatal conductances were greater for mycorrhizal plants, but were unaffected by daylength. Phosphorus levels in leaf tissue from mycorrhizal plants were threefold greater than those in non‐mycorrhizal plants and P levels were slightly greater in plants grown under long‐day photoperiods. Root exudation of reducing sugars was greatest for non‐mycorrhizal plants grown under long day photoperiods, but exudation of amino acids was variable. The results suggested that plants grown under long‐day photoperiods have greater basipetal transport of photosynthates resulting in improved mycorrhizal infection and plant growth response.

Lipid Composition ofZea maysSeedlings and Water Stress-Induced Changes

The imposition of a polyethylene glycol-induced osmotic stress of-1-5 MPa for 48 h on 28 d old Zea mays (cv. Style Pak) seedlings resulted in a 44% decreased stem dry weight and increased triglyceride levels in stem and leaf tissues; increased steryl ester levels also occurred in stems. The magnitude of these increases was such that, on a dry weight basis, there were increased total triglyceride and steryl ester levels in the seedlings after the 48 h applied stress. In stems the increased triglyceride level was evident in all of the component fatty acids examined, whereas in leaves it was associated mainly with one fatty acid component, viz. linolenic acid (C18:3). Changes in sterol levels were small but significant and largely restricted to the stem. Proline levels of all three tissues increased in response to water-stressing the seedlings and the greatest increase also occurred in the stem tissues.

A FIELD COMPARISON STUDY OF AMMONIUM PHOSPHATES AND SUPERPHOSPHATE–UREA OR AMMONIUM NITRATE ON CORN (ZEA MAYS L.) GROWTH IN FIVE QUEBEC SOILS

Effects of mono-, diammonium, and superphosphate with added urea or ammonium nitrate on corn (Zea mays L.) growth were studied in the field in 1971 and 1972. At the rate of 100 kg P2O5/ha, none of the carriers affected emergence of seedlings in five Quebec soils. Leaf P content at silking time was of little benefit in predicting P status of the plants, or in differentiating among the carriers. Phosphorous applications gave significant corn yield increases, with carriers performing alike when averaged over all sites. However, some yield differences among carriers occurred on some soil types and seasons. These carrier differences were not consistent and remain to be clarified. The ammonium phosphates compared with the check generally hastened maturity but reduced potassium levels in leaf tissue of corn.

Effect of water stress on abscisic acid levels in white lupin (Lupinus albus L.) fruit, leaves and phloem exudate

Abscisic acid (ABA) was identified by combined gas liquid chromatography-mass spectrometry in sieve-tube exudate collected from the cut stylar ends of white lupin fruit. Water stress caused an increase in ABA levels in leaf, seed and pod tissues and phloem exudate. When compared with levels in extracts of these tissues, the concentration of ABA in sieve-tube sap was very high. It is suggested that ABA is actively transported out of mature leaves in the phloem and this finding is discussed in terms of the ABA balance of the plant.

Nitrogen Requirement of the Highbush Blueberry, Vaccinium corymbosum L.1

Abstract Field applications of N greater than 34 kg/ha to highbush blueberry plants on an Atsion sand did not result in increased fruit production. Application of more than 64 kg N/ha may be detrimental to blueberry production. The optimum N content in the median leaves sampled one month after harvest of lateral shoots averaged 1.65% N over a 5 year period. A biennial bearing pattern occurred consistently at each of N fertilizer levels. Leaf N levels tended to be lower during years of high production than during years of low fruit production. Ca levels in leaf tissue were found to be below the sufficiency level during low production years when leaf N was high and above the sufficiency level in high production years when leaf N was lower.

Critical Level of Airborne Sea Salt Inducing Foliar Injury to Bean1

Abstract Phaseolus vulgaris L. cv. Contender (green bean) treated with sea salt aerosols, similar to ambient seashore conditions displayed foliar injury from exposures of 8, 168, and 480 hr at sedimentation rates of 27, 5.7 and 1.5 μg/m2/sec, respectively. Sodium and chloride uptake was linear with time. Toxicity symptoms corresponded with a critical leaf tissue level of 2.6% Cl regardless of exposure time or sedimentation rate.

CALCIUM DEFICIENCY SYMPTOMS IN GREENHOUSE CUCUMBERS

In a sand culture experiment with seeded and seedless greenhouse cucumbers (Cucumis sativus L.), induced Ca deficiency over a range of nutrient Ca applications produced characteristic foliar and plant symptoms. Severe deficiency was associated with top leaf tissue levels of 0.20% Ca and less. Fruit symptoms were a proportionate stunting, center and stem-end constriction in Burpee hybrid, and a progressively darker green color in Sporu. Mild symptoms were difficult to recognize and could only be confirmed by tissue analysis, although it was not possible to determine an exact threshold value for incipient deficiency.

EFFECTS OF NITROGEN, PHOSPHORUS, POTASSIUM, AND MANURE FACTORIALLY APPLIED TO POTATOES IN A LONG-TERM STUDY

The effects of N, P, K, and manure factorially applied to potato (Solanum tuberosum L.) yields, starch content, and soil and tissue nutrient levels were evaluated on continuous plots over 12 yr in a 4-yr potato, grain, hay, hay rotation. Although yield responses were observed with N, P, and K applications, manure application substantially increased yields above yield levels due to applied N, P, and K. Increasing rates of KCl strongly depressed tuber starch contents. Soil test P and K levels increased with repeated fertility applications, and leaf tissue levels were increased with N, P, and K treatments.

Effects of controlled release and liquid fertilizers on the growth and mineral composition of Celosia Plumosia

Abstract A resin coated fertilizer (Osmocote3) was tested at 2 rates in combination with a normal greenhouse liquid fertilization (LF) program. A low rate of Osmocote in combination with LF produced superior growth and had equivalent N, P and K leaf tissue levels compared to a high rate. Delayed application of LF for 3–7 waterings significantly improved the substance of leaf and root tissue probably because of decreased damage of tender young roots from high soluble salts. Growth and tissue analyses (N, P and K) indicated only the need of nitrogen in LF suggesting the remainder of fertilizer constituents contribute only to soluble salt problems.

The influence of foliar and substrate application of manganese on cotton

In sand culture the optimum nutrient solution manganese concentration for cotton is on the order of 3 ppm. Good growth and fruiting were obtained at 27 ppm while 81 ppm proved to be highly toxic. Cotton plants containing 3000 ppm leaf manganese appeared normal and exhibited only a small reduction in growth. Leaf tissue levels in excess of 4000 ppm were highly toxic. In relation to tissue manganese, cotton is classified as a highly tolerant species.