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- Author or Editor: M. James Tsujita x
Abstract
Supplemental high pressure sodium (HPS) night lighting during propagation increased early growth and rooting of Chrysanthemum morifolium Ramat. cv. White Marble cuttings planted in October, and early growth only in cuttings planted in January. The results depended on the ambient light conditions and the level of supplemental HPS irradiance. Flower quality was enhanced by the supplemental light treatments only in the October plantings. Improving ambient light conditions as the crop developed apparently compensated for poor light conditions during the rooting period of the January planting.
Chrysanthemum morifolium Ramat. cv. `Yellow Favor' was grown single stem in 10cm pots on an ebb and flow benching system. A 2×2 factorial design was employed with 2 sources of N (100 NO3 and 50 NO3 :50 NH4 +), delivered at 18 mM, and 2 quantities of N supplied, (200 mg and 400 mg), with 200 mg supplied by wk 3 and 400 mg supplied by wk 5. Plants were harvested at two wk intervals, separated into leaves, stems plus petioles and inflorescence (when developed) and analyzed for total and NO3 - N, with reduced N being estimated as the difference between these two values. Plant tissue (leaves and stems plus petioles) NO3 - levels showed similar trends for the 200 and 400 mg N supply, with a maximum at the 4th to 6th wk. At flowering, (wk 10) significant tissue NO3 - levels were found only in plants supplied 400 mg of N. Plants supplied with 50:50 NH4 +: NO3 - initially had significantly greater reduced N and leaf area than NO3 - supplied plants, although differences diminished towards flowering. During floral development (wk 8 to 10), at which time no additional N was accumulated by the plant, significant amounts of reduced N was remobilized from the stem plus petioles and leaves to the developing inflorescence.
Excessive supply of fertilizer N can lead to inefficient use of supplied N and consequently affect plant quality. Reduction of supplied fertilizer N can possibly increase plant N usage efficiency and improve quality. Chrysanthemum morifolium Ramat. cv. `Yellow Favor' was grown single stem in 10 cm pots on an ebb and flow benching system. All plants received 18.5 mM NO3 - N, until the mid point of this ten wk crop, at which time the following NO3 - concentrations (mM) were employed: 18.5, 15.5, 12.5, 9.5, clear water and clear water alternating with 18.5 mM NO3 -. Plants were harvested at two wk intervals, cut in half and separated into leaves, stems plus petioles and inflorescence (when developed). Plant tissue from the lower half of the plant was analyzed for total and NO3 - N, with reduced N being estimated as the difference between these two values. All growth parameters measured did not significantly differ, although termination of N fertilization (clear water) and reduction of NO3 - level to 9.5 mM significantly reduced NO3 - levels in the lower leaf and stem plus petioles, with a concomitant increase in reduced N in these tissues, over the 6-10 wk period. Total amounts of N accumulated in plant tissues analyzed did not differ significantly at flowering.