Abstract
The mineral composition of grasses commonly used for turf has received little study. This is especially so for the micronutrient elements. Some data are available for grasses grown under pasture conditions (7), however, most of these grasses and their method of culture are quite different from turfgrasses. The paucity of information on turfgrasses prompted this survey of the mineral composition of several grasses commonly used for ornamental purposes. The grasses studied were grown in the field under a maintenance program typical of that used for turfgrasses. The results should be of value for future comparisons where nutrient toxicities, deficiencies or imbalances are suspected.
Abstract
Tomato plants develop dark, pitted stem lesions when grown on ammonium nutrition in soil culture with insufficient potassium, (1,4,5). Ammonium utilization by plants requires a higher potassium level than nitrate utilization (10). Furthermore, when ammonium salt solutions are applied to soils, potassium may be fixed in the clay lattices by ammonium ions (2). Hence, the potassium supplying power of the soil is lowered, and plants are unable to obtain enough potassium to meet their needs. In sand culture, stem lesions occur only when potassium salts are excluded from the nutrient solution with ammonium as the sole nitrogen source (1). Lesions do not develop during potassium deficiency with nitrate sources of nitrogen.
Abstract
Using a nutrient solution providing 375 μmol calcium (Ca) to each plant, 40 cauliflower (Brassica oleracea, Botrytis) strains were evaluated for growth under low-Ca stress. The most efficient strain produced 14 times the dry matter as the least efficient. Calcium efficiency ratios (mg plant dry matter produced per mg Ca in tissue) differed by a factor of 3 between Ca-efficient and Ca-inefficient strains. Increased Ca accumulation and increased Ca utilization contributed to the increased growth by cauliflower strains under Ca deficiency.
Our objective was to determine the effects on plant growth and physiology that a photodegraded Fe-chelate containing lab-prepared nutrient solution would have when used in plant culture. Plants grown hydroponically in the irradiated Fe-DTPA containing nutrient solution had ferric reductase activity 2.2 times greater, foliar Fe level 0.77 times less, and foliar Mn level 1.9 times greater than in plants grown in an identical but non-irradiated solution, indicating that plants growing in the irradiated solution were responding to Fe deficiency stress with physiological reactions associated with Fe efficiency. The youngest leaves of plants that were grown in the irradiated solution had symptoms of Mn toxicity. Restoration of the irradiated solution by removing the precipitated Fe by centrifugation and adding fresh Fe-chelate resulted in plants that were, in general, not different from those grown in the non-irradiated solution (control).
Abstract
Cold stress resistance of ‘Redcoat’ strawberries (Fragaria x ananassa Duch.) grown under several fall fertilization nutrient regimes was determined by artificial freezing. Stress resistance was determined at the onset of acclimation, October 15, and in midwinter with fully hardened plants. The least tolerant plants during the onset of acclimation were those with nutrient deficiencies, those with high N and low P and K and those with a high imbalance of K, whereas the most tolerant plants resulted from fertilizer applications of balanced NPK and balanced NPK plus high P (1:2:1). Fully hardened plants, artificially frozen to -9°C, -11° and -13° crown temperature showed similar stress responses to fertilization except that plants given high N plus P and K were more tolerant than in the October freeze test. Tissue analyses showed that plants with the highest ratio of P/K in crown and root tissues were also the most resistant to cold stress.
Abstract
The root defect of carrot (Daucus carota L.) called cavity spot is injury due to feeding of the fungus gnat larvae, Bradysia impatiens (Joh.). In sand cultures and in the field, carrots treated with the systemic insecticide, aldicarb (2-methyl-2(methylthio) propionaldehyde 0-(methylcarbamoyl) oxime) were free of the defect. The symptoms of cavity spot on carrot roots grown in sand culture were the same as those on field-grown roots. Eliminating Ca from the nutrient solution reduced the Ca content of roots and leaves but had no effect on the incidence of cavity spot. Plants with Ca-deficiency symptoms on the foliage produced roots that, except for size, were indistinguishable from roots of plants receiving the complete nutrient solution.
Abstract
Boston fern [Nephrolepis exaltata (L.) Schott ‘Rooseveltii’] was grown with sufficient and insufficient levels of N and K and leaf nutrient concentrations were determined periodically from 4 frond sections: frond tips, 10–12 cm; frond midsections, 10–12 cm; frond bases, 10–12 cm; and whole fronds, 30–40 cm. Both the frond midsection and the whole frond were found to be acceptable for foliar analysis. Frond tips had the lowest nutrient concentrations for most elements. Foliar N was similar for all frond sections sampled. Nitrogen deficiency symptoms occurred after 2 to 4 weeks of minus N conditions. When three N sources were added to plants grown under minus N conditions, N source had a limited influence on N uptake as measured by foliar analysis. One and 2 weeks after N treatment was restored to N-deficient ferns, foliar N had increased 55 and 100%, respectively.
Lowbush blueberries (Vaccinium angustifolium Ait.) in three commercial fields were treated with 67.2 kg P/ha from triple super phosphate(TSP), monoammonium phosphate (MAP), or diammonium phosphate (DAP), and compared to a control in a randomized complete block design with 12 blocks. Correction of P deficiency by fertilizers with different ratios of P to N was assessed by leaf and stem nutrient concentrations and contents (concentration × weight). Samples of stems collected in July from three 0.03 m2 quadrates per treatment plot indicated MAP and DAP had no effect on dry weight of stem tissue, but increased average dry weight of leaf tissue. Leaf nutrient concentrations and contents showed similar results; P and N were raised to higher levels by MAP and DAP than by TSP. TSP had no effect on leaf N concentration or content but raised leaf P concentration but not content, compared to controls.
Response surface methods refer to a set of experimental design and analysis methods to study the effect of quantitative treatments on a response of interest. In theory, these methods have a broad range of applicability. While they have gained widespread acceptance and application in manufacturing and quality improvement research, they have never caught on in the agricultural sciences. We propose that this is because there has not been specific research demonstrating their usage. In this paper, two 34 factorial experiments were performed using 100 poinsettia plants (Euphorbia pulcherrima Willd. ex Klotzsch) to measure nutrient element concentrations in leaves at three rates each of nitrogen (N), sulfur (S), iron (Fe), and manganese (Mn). Three different methods of analysis were compared—the standard analysis of variance with no regression model, the quadratic regression model commonly assumed for most standard response surface methods and the Hoerl model regression, a nonlinear alternative to quadratic response. Actual nutrient element values were compared with the values predicted by each regression model and then also evaluated to see if the visual symptomology of yellowing related to those nutrient concentrations in leaves. The Hoerl model demonstrated better ability to detect biologically relevant nonlinear two-, three-, and four-way nutrient interactions. Though there was minimal replication this model characterized the treatment effects while keeping the size of the experiment manageable both in terms of time (labor) and cost of plant analyses. Additionally, it was shown that when S, Fe, and/or Mn were deficient along with N, their visual deficiency symptoms were masked by the overall yellowing associated with N deficiency. This model is recommended as the initial experiment in a series where scientists are looking to expand information already determined for two factors. Other treatment systems that this can be used with include: levels of irrigation, pesticides, and plant growth regulators.
Abstract
Differential plant response to Ca-deficiency stress was investigated by screening 138 tomato lines (Lycopersicon esculentum Mill.) in nutrient solution at 10 mg of Ca per plant. Dry weight produced during vegetative growth and severity of Ca-deficiency symptoms were used to classify plants as efficient and inefficient. Efficiency in Ca utilization within the plant was defined and expressed as the mg of dry weight produced for each mg of Ca absorbed by a plant (CaER). Three of the most efficient and 3 of the most inefficient lines were selected for additional studies. The efficient lines produced an average of 81% more dry weight than the inefficient lines at 10 mg of Ca. Comparable amounts of dry weight were produced by all lines at 400 mg of Ca per plant. Two factors were responsible for greater dry weight production under Ca-deficiency stress: more efficient utilization of tissue Ca and greater ability to absorb Ca from low-Ca solutions. Inheritance studies indicated that additive gene effects made major contributions to variations in response to low Ca. A simple additive-dominance model was adequate to explain differences in CaER, with additive effects highly significant. Some interallelic interactions appear to be important for total plant dry weight inheritance.