Easter Lily Growth And Development PDF Download

Investigations were undertaken to study in detail the responses of the Easter lily bulb, Lilium longiflorum Thunb., to storage. The primary objectives were 1) to characterize the morphological response of the plants to a range of conditions during bulb storage and 2) to identify those factors controlling floral initiation. 'Croft', 'Ace' and 'Green Croft' bulbs were subjected to various storage temperature sequences. The influences of date of bulb harvest in relation to storage duration, the atmosphere surrounding the bulbs during storage, and the moisture content in the packing material were also studied. Results showed that bulbs were never dormant during storage and their development seemed to be Impaired only by the environmental conditions surrounding them. Temperatures of 60° and 70° F, which are generally most favorable for growth of the lily plant, also were most favorable for bulb development. No flower buds were initiated during the storage period. Bulb storage at 40° F, with 30° F being nearly as effective, affected the forced plants the most, because the plants flowered quickest, were the shortest, initiated fewest flowers and leaves, and had the shortest leaves. That floral induction occurred earliest in bulbs stored at 40° F is shown by the fact that their plants had the smallest foliar leaf complement. Evidence that floral initiation occurred after bulb storage is the stepwise reduction in the leaf complement with each Increase in storage time up to 12 weeks at 40° F. That temperatures above and below 40° F prolonged the vegetative phase is evinced by the greater leaf complements on plants grown from bulbs stored at those temperatures. Storage at any of the temperatures was more effective than no storage, however, in terminating the vegetative phase and inducing floral initiation because the plants grown from non-stored bulbs were the leafiest of all. Storage temperatures that encouraged the stem apex to Initiate large numbers of leaves, that is delay floral induction, also encouraged the initiation of larger numbers of flowers once floral initiation started. Days to force the lily to bloom were generally proportional to the number of leaves to be initiated, expanded, or both. Exposure of the packing material and bulbs to as little as two weeks of 70° F storage temperature dehydrated the bulbs and their forcing performance was less desirable unless they were stored in polyethylene bags. Without the protection of the polyethylene film, they took longer to flower, produced fewer flowers on the 'Croft' lilies, and were too tall. Storage of the bulbs in the sealed polyethylene bags had no detrimental effects. The results provided evidence such storage is beneficial under conditions where excessive drying might otherwise occur. Respiration patterns of bulbs suggested that two physiological systems were active during bulb storage. One system was primarily active at temperatures near 40° F, temperatures favorable to floral initiation. The other system was more active at temperatures near 70° F and was noninductive, since these temperatures favored vegetativeness. Bulbs harvested early had a greater flowering potential and required a longer forcing time than bulbs harvested later.