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  • Author or Editor: William S. Sakai x
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Seasonal flowering behavior of Heliconia wagneriana Petersen was found to be caused by short daylengths (SD) using artificial short days (8 to 9 hours) and long days as daylength extension or night break lighting with incandescent lamps. The natural time for flower initiation was estimated to be mid- to late October (11 hours 40 minutes to 11 hours 20 minutes) in Hawaii, and 120 to 150 days were required from the onset of inductive SD to inflorescence emergence. The results may be used to manipulate flower availability for flower markets.

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Anthuriums appear to be very salt sensitive. Small plants of Anthurium andraeunum `Marian Seefurth' were fertilized daily with 25, 50, 75, 100, and 125 ppm N of 12N-16P-30K + micros (75% nitrate-25% ammonium) liquid fertilizer corresponding to 0.50, 0.74, 0.98, 1.22, 1.45, and 1.69 mS·cm-1 of electrical conductivity (EC). After 1 year, flower production was greatest [5.2 flowers per plant (fl/pl)] at 0.50 mS·cm-1 (25 ppm N). Flower production decreased gradually with increasing EC to 3.9 fl/pl at 1.45 mS·cm-1 (125 ppm N), then dropped to 1.8 fl/pl at 1.69 mS·cm-1 (150 ppm N). Flower stem length and flower size followed the same pattern. With larger `Ellison Onizuka' plants, the number of flowers, flower stem length, and flower size all peaked at 0.74 mS·cm-1 (75 ppm N). A drop was again observed at 1.69 mS·cm-1 (125 ppm N). Other workers recommend 0.60 to 0.80 mS·c m-1 for anthurium production. Our findings are in agreement. However, for smaller plants, 0.50 mS·cm-1 would produce better growth.

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Abstract

The abscission of young Macadamia integrifolia Maiden & Betche fruit was investigated in vitro with explants consisting of a single fruit attached at the distal end of a segment of the peduncle. A 30% reduction in fruit removal force (FRF) of explants incubated in distilled water was evident within 48 hr after excision and was correlated with increased ethylene production. Pretreatment of explants with 5 and 10 mm ethephon accelerated FRF reduction. Pretreatment with increasing concentrations of silver nitrate (AgNO3) to 1.47 mm or AOA to 0.05 mm, inhibited the reduction in FRF. FRF reduction also was inhibited by 1000 μm NAA and 100 pM 2,4-D. GA3 and BA had no effect. Chemical names used: (2-chloroethyl)phosphonic acid (ethephon); 1-naphthaleneacetic acid (NAA); (2,4-dichloro- phenoxy)acetic acid (2,4-D); gibberellic acid (GA3); N-(phenylmethyl)-H-purin-6-amine (BA); (aminooxy)acetic acid (AOA).

Open Access

Infection of Anthurium andraeanum Andre by Xanthosomas campestris pv. dieffenbachiae appears to be through hydathodes. Hydathodes occur around the entire margin of the leaves. A small vein that runs parallel to the margin delimits the outer edge of the mesophyll chlorenchyma and the inner edge of the hydathode. External to the vein, epithem cells and intercellular spaces occur adjacent to the xylem vessel elements. Hydathode pores mostly occur on the adaxial surface of the leaf margin. Hydathode structure is consistent and does not appear to differ among cultivars. Glutamine may occur in the guttation liquid with higher levels of nitrogen nutrition. At the same level of nitrogen, more susceptible cultivars appear to produce more glutamine than cultivars more tolerant to the blight. More glutamine appears to increase the rate of blight infection.

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Abstract

Two types of raphides and 2 types of raphid idioblasts were observed in Dieffenbachia maculata (Lodd.) G. Don cv. Rudolph Roehrs. Small raphides, about 25 μm long and 0.4 μm wide, with barbs and grooves were found in idioblast cells similar in shape to adjacent ground parenchyma cells. Larger raphides, about 120 μm long and 4 μm wide, with wide grooves were found in spindle shaped, obtuse ended idioblasts, about 165 μm long and 40 μm in diameter.

Open Access

Abstract

Leaves of ‘Mountain Snow’ chrysanthemums (Chrysanthemum morifolium Ramat.), sprayed with 10 mm NAA or 10 mm NAAEE, exhibited severe epinasty after 24 hr, while leaves sprayed with 5 mm ethephon did not. Treatment with 100 μm AOA 24 hr before application reduced ethylene production rate of leaves, but not epinasty. Localized application of NAA to adaxial, abaxial, or both leaf surfaces resulted in similar amounts of leaf epinasty. Epinastic leaves had enlarged adaxial epidermal cells. Size of abaxial epidermal cells was unchanged. This study provides evidence that leaf epinasty of chrysanthemum following NAA application is not the result of auxin-induced ethylene production. Chemical names used: (aminooxy)acetic acid (AOA); 1-naphthaleneacetic acid (NAA); 1-naphthaleneacetic acid ethyl ester (NAAEE); and (2-chloroethyl)phosphonic acid (ethephon).

Open Access