1993 Volume 62 Issue 3 Pages 595-600
The effects of high, moderate, and low light intensities on floral induction and nitrogen nutrition in Phalaenopsis grown at 23°/18°C, 28°/23°C, and 33°/28 °C (day/night) were ascertained.
1. High light intensity substantially increased total dry matter, sugar content, and nitrogen absorbed. The differential in C assimilation and N uptake resulted in larger plants having lower N content under high light intensity.
2. The number of expanded leaves, the growth of roots, and the amount of dry matter produced per plant increased under proportionately higher light intensities.
3. High light intensity preceding 23°/18°C treatment increased the number of in- florescence, but the 28°/23°C treatment advanced their time of emergence to plant exposed to lower light intensities. The temperature sensitivity for floral induction increased in those plants which produced relatively more dry matter per unit N absorbed (larger C/N balance).
To increase the sensitivity of Phalaenopsis plants to floral induction, they should be grown under high light intensity; because these conditions lead to high sugar content, which in turn, seemingly expedite rapid metabolism of nitrogen.