The Influence of Light on Lily (Lilium longiflorum Thunb.). I. Influence of Light Intensity on Plant Development1

Abstract

Lily plants were exposed to natural daylight (ND), 50% ND (50% saran), ND plus 16 hours of incandescent (Inc) or ND plus 16 hours of high pressure sodium discharge (HID) lamp light at both University of Minnesota and Michigan State University. Light intensity had no significant horticultural effect on plant development rate that could not be readily explained by temperature. The Inc or HID light source hastened flowering by 5 to 8 days over the ND plants when given from emergence to flower. However, the rate of development from visible bud to flower was not influenced by light intensity. Plant heights were increased by all light treatments when compared to the ND plants. These increases appeared due to photoperiod for the HID treated plants, photoperiod and light quality for the Inc treated plants, and light quantity for the 50% saran-treated plants. The number of flower buds initiated was not affected by light treatment but Inc lighting increased flower bud abortion. Final plant height was highly correlated with height at visible bud; final height being about double the height at visible bud when plants were grown continuously under ND, HID, or 50% saran.

The Influence of Light on Lily (Lilium longiflorum Thunb.). II. Influence of Photoperiod and Light Stress on Flower Number, Height, and Growth Rate1

“…However, differences in total flower bud number were small with a maximum increase for only 0.9 flower buds when plants were lighted from 30-40 days after E (Table 2). Heins, et al (9) found that during vegetative or early reproductive growth, neither con tinuous supplemental high intensity discharge (HID) lighting, nor 50% saran shading, influenced flower bud number. However, long term (30 day) Inc lighting reduced bud number (9).…”

“…Heins, et al (9) found that during vegetative or early reproductive growth, neither con tinuous supplemental high intensity discharge (HID) lighting, nor 50% saran shading, influenced flower bud number. However, long term (30 day) Inc lighting reduced bud number (9). We note that temperatures were not lowered as reported by Roh and Wil kins (16) during floral initiation to possibly increase flower bud numbers.…”

“…from fully programmed lily bulbs (Table 2). Thus, the rate of de velopment is not dependent on light but apparently is a function of temperature (9,15,21).…”

“…To maintain plant quality, light intensity must also increase as tem perature increases. However, light does not hasten these phys iological processes; temperature is responsible (9,15,21). Our past work on lily did not show a hastening or retarding of flower ing from increased or decreased light quantity at a uniform tem perature during flower bud elongation (9).…”

Quantifying Temperature-controlled Leaf Unfolding Rates in ‘Nellie White’ Easter Lily

“…Information on quantitative relationships between the environment and rate of lily leaf unfolding is limited (9,17,18,22). Photosynthetic photon flux (PPF) and photoperiod have been shown to be minor factors affecting leaf unfolding rates and time of development (10,11). Grueber et al (9) reported on leaf unfolding rates for lilies forced in growth chambers for a wide range of temperatures; however, no functional relationship was presented.…”