| Summary: | 碩士 === 國立臺灣大學 === 園藝學研究所 === 89 === Effects of different nutrient concentration on growth and plant height were investigated in Salvia splendens, Impatiens wallerana, Coleus, and Melampodium paludosum grown with ebb-and-flow system and hand-watering systems. Attempting to reduce plug seedlings height, different phosphorus concentration, seed pretreatment, and foliar spray treatment with paclobutrazol were also studied.
Salvia splendens, Impatiens wallerana, Coleus, and Melampodium paludosum grew well with an ebb and flow system, and no negative effects were found. In seedlings stage, one half strength of Johnson’s solution was optimum to the growth of Salvia splendens, Impatiens wallerana, Coleus, and Melampodium paludosum. With full-strength of Johnson’s solution application, the growth of root was reduced. After transplanting to 11 cm pot, full-strength of Johnson’s solution was optimum for the growth of Salvia splendens; half strength to Impatiens wallerana, and 1/4-strength to Coleus, which was required leaching.
Phosphorus deficiency reduced the height of seedlings Salvia splendens, Impatiens wallerana, Coleus, and Melampodium paludosum. Howerever, flowering date was delayed in Salvia splendens. Impatiens wallerana was the most sensitive to phosphorus deficiency. When phosphorus deficiency in plug stage, plant sizes of Impatiens wallerana were smaller and the number of branches and flowers were decreased after transplanting to 11 cm diameter pot. Number of flowers of Melampodium paludosum were also decreased with phosphorus deficiency.
Height of plug seedlings was decreased when seed were treated with paclobutrazol prior to sowing. However, the germination time was delayed and the germination percentage was decreased at high paclobutrazol concentrations treatd with 24 hours. Germination of Salvia splendens was the most the most sensitive to paclobutrazol. After Salvia splendens seeds imbibed paclobutrazol solution of 100 ppm for 24 horus, the germination percentage was decreased to 60%.
Application of paclobutrazol with foliage spray was more effective to reduce plug seedlings height than seed treaded. The optimum range was from 10 to 30 ppm in Salvia splendens, 10 to 20 ppm in Impatiens wallerana, and at 5 ppm in Melampodium paludosum.
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