Easter lilies (Lilium longiflorum Thunb. `Nellie White') were placed at three spacings of about 11, 22, or 44 plants per square meter (plants/m2). Above canopy light intensities, measured weekly at noon, ranged from 107.3 to 704.5 μmol·s–1·m–2 and were not significantly different among spacings. Mid canopy light intensities ranged from 16.5 to 229.0, 43.0 to 458.5, and 77.5 to 535.3 μmol·s–1·m–2 at spacings of 44, 22 and 11 plants/m2, respectively. On February 5, 1996, three plants from the 22 plants/m2 spacing were sprayed with a solution of 0.5 ml·L–1 of 1.8% (a.i.) of each of N-(phenylmethyl)-IH-purine-6-amine and gibberellins A4A7; and on March 5, three additional plants from each spacing were similarly sprayed. Beginning 5 Mar., weekly counts were made of yellow and brown leaves on all treated and control plants. Average per plant numbers of brown leaves increased on control plants at all spacings but increased on treated plants only at the 11 plants/m2 spacing. On 25 Mar., control plants averaged 15.6, 12.1, and 15.3 brown leaves per plant at spacings of 11, 22, and 44 plants/m2, respectively, while plants treated on March 5 averaged 10.7, 9.0, and 10.7 brown leaves. Plants treated on 5 Feb. averaged 3.5 brown leaves per plant and had an average mid leaf length of 13.8 cm compared to about 10.5 cm for all other plants. Spacing had no effect on average yellow or brown leaves per plant. This study demonstrated that early applications of Promalin can reduce leaf senescence which may occur during forcing time before bud appearance to opening of first bud. Some leaf enlargement may occur on plants treated very early.
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