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Yin-Tung Wang

Foliar application of 500 or 1000 mg BA or PBA/liter to stock plants of golden pothos [Epipremnum aureum (Linden & Andre) Bunt.] induced axillary bud elongation but did not promote growth of cuttings taken from these stock plants. Cuttings from plants treated with BA + GA4+7, each at 1000 mg·liter-1, died. Plants grown under 1000 μmol·s-1·m-2 had more but smaller leaves than those under 420 μmol·s-1·m-2. Cuttings produced under the higher light level grew more rapidly. Leaf area increased while stem length decreased as Osmocote slow-release fertilizer (18N-2.6P-10K) increased from 4 to 16 kg·m-3. A 24N-3.5P-13.3K water-soluble fertilizer applied at the rate of 0.42 g/500 ml weekly produced the best plants and resulted in the best cutting growth. Cuttings taken from stock plants receiving Osmocote at 4 kg·m-3 grew slower than those produced at other rates. Placement of cuttings in a mist-propagation bed for 1 or more weeks resulted in an accelerated growth rate relative to nonmisted cuttings. Chemical names used: N-(phenylmethyl)-1H-purin-6-amine (BA); N-(phenylmethyl)-9-(tetrahydro-2H-pyran-2-yl)-9H-purin-6-amine (PBA); (1α,2β,4aα,10β) 2,4a,7-trihydroxy-l-methyl-8-methylenegibb-3-ene-1,10-dicarboxylic acid l,-4a-lactone (GA4+7).

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Wen-Shaw Chen

The changes in cytokinins and gibberellins in xylem sap of lychee (Litchi chinensis Sonn. cv. Heh yeh) trees were investigated at the stages of leaf expansion, dormant bud (when apical leaves are dropped), 30 days before flower bud formation, flower bud formation, and full bloom of grafted field-grown lychee trees. Also; the diffusible IAA and ABA in diffusate from shoot tips were examined at the successive stages of development. High gibberellin was found in the xylem sap at the stage of leaf expansion. A constant level of IAA was maintained through the five growth stages. At 30 days before flower bud formation, ABA increased dramatically. Concurrently, total cytokinin content increased in the xylem sap, reaching a maximum during flower bud formation and full bloom. Gibberellin content in the xylem sap was at a low level 30 days before flower bud formation and through the stage of flower bud formation.

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Richard J. McAvoy

Lilium longiflorum Thunb. cv. Ace grown without plant growth regulators and plants drenched with 0.5 mg a.i. ancymidol per pot following shoot emergence were compared to plants growing in a medium containing uniconazole-impregnated amendments. Uniconazole was applied at rates of 0.18, 0.018, and 0.0018 mg a.i. per pot using either impregnated rockwool (RW) or copolymer acrylamide acrylate (CA). Two other treatment groups received a uniconazole drench at potting (0.018 or 0.0018 mg a.i. per pot). Impregnated CA resulted in undesirably short lilies (i.e., plants <1.5 times the height of the pot) when 0.18 mg uniconazole per pot was incorporated into the medium; effective height control was obtained with CA at 0.018 mg/pot; no height control was observed at 0.0018 mg/pot. Similarly, final height of lilies grown in medium containing uniconazole-impregnated RW decreased as the rate of uniconazole increased. Pre-emergence potting medium drenches with uniconazole (0.018 and 0.0018 mg a.i. per pot) did not significantly affect lily growth and flowering. Ancymidol drench was less effective at retarding stem length and plant height than medium incorporation of 0.18 mg uniconazole. Flowering was not significantly affected by any treatment. Chemical names used: a-cyclopropyl-a-(4-methoxy-phenyl)-5-pyriimidine methanol(ancymidol);B-[(4-cyclophenyl)methyl]-a-(1,1-dimethylethyl)1 H-1,2,4-triazole-1-ethanol(paclobutrazol);(E)-(p-chloro-phenyl)-4,4-dimethyl-2-(1,2,4-triazol-1-yl)-1-penten-3-ol(uniconazole).

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Shiow Y. Wang, Miklos Faust, and Hong J. Jiao

The effects of thidiazuron on changes in superoxide dismutase (SOD) activity in apple (Malus domestica Borkh cv. York Imperial) buds during dormancy break were determined. Dormant buds had low SOD activity. Increased SOD activity was correlated with budbreak induced by thidiazuron. Buds contained three distinct forms of SOD: Cu, Zn-SOD; Mn-SOD; and Fe-SOD. Most of the SOD activity in apple buds was attributed to Cu and Zn-SOD, followed by Mn-SOD. Iron-SOD was not present in dormant buds, and only a trace amount was found as buds started rapid expansion. Chemical name used: N-phenyl-N′-1,2,3,-thidiazol-5-ylurea (thidiazuron).

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Stephen M. Southwick and James T. Yeager

185 ORAL SESSION (Abstr. 723-730) FRUIT CROPS: GROWTH SUBSTANCES

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R. Nunez-Elisea, M. L. Caldeira, and T. L. Davenport

185 ORAL SESSION (Abstr. 723-730) FRUIT CROPS: GROWTH SUBSTANCES

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Daniel L. Ward and Bradley H. Taylor

185 ORAL SESSION (Abstr. 723-730) FRUIT CROPS: GROWTH SUBSTANCES

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Sher-Muhammad and Bradley H. Taylor

185 ORAL SESSION (Abstr. 723-730) FRUIT CROPS: GROWTH SUBSTANCES

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Moritz Knoche and Martin J. Bukovac

185 ORAL SESSION (Abstr. 723-730) FRUIT CROPS: GROWTH SUBSTANCES

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R. Nunez-Elisea, M. L. Caldeira, and T. L. Davenport

185 ORAL SESSION (Abstr. 723-730) FRUIT CROPS: GROWTH SUBSTANCES