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  • Author or Editor: Douglas A. Bailey x
  • Journal of the American Society for Horticultural Science x
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Abstract

In the article “Evaluation of Nutrient Deficiency and Micronutrient Toxicity Symptoms in Florists’ Hydrangea”, by Douglas A. Bailey and P. Allen Hammer (J. Amer. Soc. Hort. Sci. 113(3):363–367, May 1988), the following corrections should be noted: 1) In Table 3, percent dry weight of N for the –N treatment should read “1.40”, not “4.40”; 2) the significance levels in footnote z of Table 3 should read “0.05 ≥ α ≥ 0.01 (*), at 0.01 ≥ α > 0.001 (**), or at α ≤ 0.001 (***)”; 3) Tables 4 and 5 are numbered incorrectly—they should be switched; and 4) the significance levels in footnote z of the renumbered Table 5 should read “0.01 ≥ α > 0.001 (**) or at α ≤ 0.001 (***)”.

Open Access

Abstract

All growth retardant treatments (ancymidol, 50 mg·liter−1, one or two sprays; uniconazole, 5, 10, or 15 mg·liter−1, one or two sprays; 20 mg·liter−1, one spray) reduced Easter lily (Lilium longiflorum Thunb.) plant heights when compared to controls. Plant heights decreased linearly with increasing concentration of uniconazole for both one- and two-spray treatments. High concentrations of uniconazole delayed anthesis; ancymidol treatments did not. Individual corolla length was not affected by treatments. Treatments did not affect daughter bulb depletion or new daughter bulb growth. Total leaf area and leaf dry weight decreased as uniconazole concentration increased; ancymidol treatments did not affect leaf area, but did reduce leaf dry weight. Leaf total soluble carbohydrate decreased with increasing concentration of uniconazole. Chemical names used: α-cyclopropyl-α-(4-methoxyphenyl)-5-pyrimidine-methanol (ancymidol); (E)-1-(p-chlorophenyI)-4,4-dimethyl-2-(1,2,4-triazol-1-yl)-1-penten-3-ol (uniconazole).

Open Access

Abstract

Nutrient imbalances were investigated to a) document nutrient deficiency and micronutrient toxicity symptoms in florists’ hydrangea (Hydrangea macrophylla Thunb.) and b) examine the possible relationship of single-element deficiencies and toxicities with a foliar malformation prevelant on hydrangeas grown at >30°C. Plants subjected to N, P, K, Ca, Mg, S, B, Fe, and Zn deficiency and B and Mn toxicity treatments produced visual symptoms of the corresponding nutrient imbalance. Visual symptoms did not develop in +Fe, +Cu, +Zn, +Mo, −Mn, −Cu, and −Mo treatments. None of the symptoms induced were similar to the foliar malformations observed on hydrangeas grown at >30°. Hydrangea leaf malformation does not appear to be correlated with any single nutrient imbalance within hydrangea leaves. Results of the nutrient deficiency and toxicity experiments offer a diagnostic tool for interpretation of nutrient analysis of hydrangea.

Open Access

Abstract

Plants of Hydrangea macrophylla Thunb. were grown in various environments to identify factors responsible for the appearance of malformed hydrangea leaves and to screen cultivars for tolerance to the foliar disorder. Ambient temperature, photosynthetic photon flux (PPF), and root system temperature were studied. Hydrangea leaf malformation is under thermal control and can be stimulated by ambient temperatures of 33/26C (light/dark), but these must be maintained to sustain the development of distorted foliage. Placement of plants with malformed leaves into a 26/22C (light/dark) environment resulted in subsequent development of typical leaves. A PPF of 506 μmol·s−1·m−2 resulted in a more rapid appearance of distorted leaves than a PPF of 224 μmol·s−1·m−2. Reducing the root system temperature below the ambient level of 32/28C to 20/18C (light/dark) reduced, but did not prevent, the development of malformed leaves. ‘Blau Donau’ and ‘Tricolor’ did not develop malformed foliage during 22 weeks of growth at 32/26C (light/dark). ‘Rose Supreme’, ‘Merritt's Supreme’, ‘Rosa Rita’, and ‘Dr. Bernard Steiniger’ had developed malformed leaves by week 8 of treatment. For ‘Rose Supreme’ and ‘Blau Donau’, leaves developing at the higher temperatures had shorter and narrower laminae, less fresh weight and surface area, and more dry weight per unit area than plants at the lower temperatures. Laminae developing at the higher temperatures were thicker due to an increase in adaxial palisade parenchyma tissue. Malformed ‘Rose Supreme’ leaves had fewer intercellular spaces than normal leaves and lacked an observable spongy parenchyma layer. However, laminae of ‘Blau Donau’ leaves developed a distinct, yet thinner, spongy parenchyma layer at the higher than at the lower temperatures; intercellular spaces were still prevalent in the spongy parenchyma layer at the higher temperatures.

Open Access

Abstract

Plants of Hydrangea macrophylla ‘Rose Supreme’, ‘Merritt's Supreme’, and ‘Sister Therese’ produced inflorescence primordia more effectively under 8-hr photoperiods than under continuous photoperiod (CP) at 24°C. Inflorescence primordia were present on all plants under 8-hr photoperiods after 16 weeks, whereas plants under CP remained vegetative. Plants under CP sustained internode elongation throughout the experiment, whereas plants under 8-hr photoperiods remained short with little increase in number of expanded leaf pairs. Continuous photoperiod inhibited floral initiation of ‘Rose Supreme’ and ‘Merritt's Supreme’ plants at 24°C, yet had little effect at 18°C. ‘Sister Therese’ plants bloomed freely, regardless of photoperiod. Daminozide (3 biweekly foliar sprays of 5000 mg/liter) inhibited floral initiation of ‘Rose Supreme’ and ‘Sister Therese’ plants. Plants of all 3 cultivars flowered more rapidly at 24° than at 18°, whereas photoperiod had no effect on flowering date. Inflorescences were larger and plants were taller at 24°C than at 18°C. Continuous photoperiod increased inflorescence diameter and plant height at 24°C but had little effect at 18°C. Plants treated with daminozide were shorter than untreated plants, regardless of temperature or photoperiod.

Open Access

Abstract

Plants of Hydrangea macrophylla Ser. ‘Merritt's Supreme’ containing inflorescence primordia within their apical buds developed more rapidly at 24°C than at 18° or 13° minimum temperature. Three weekly applications of one ml aqueous GA3 at 100, 500, or 1000 mg/liter progressively reduced forcing time of plants grown at 24°, and the highest level increased inflorescence diameter. Plant height was increased undesirably by gibberellin treatment, and marginal foliar necrosis occurred at the 2 highest concentrations used.

Open Access