EFFECTS OF TEMPERATURE ON THE GROWTH AND FLOWERING OF ZEPHYRANTHES CANDIDA HERB

The growth periodicity of Zephyranthes candida grown outdoors and the effect of temperature on the initiation and development of flower buds were investigated. A bulb has a sympodial branching system; each unit of the sympodial branch is composed of 2 foliage leaves with a circul ar base and 1 foliage leaf with semi-circular base in 1/2 alternate ar rangement from the base upwards and terminates in an inflorescence wit h 1 floret. During the growing period, extending from spring to autumn , repeated sympodial branching results in 3-4 inflorescences. In Octob er, after the flowering season, 2 inflorescence primordia remain in ea ch bulb. The first inflorescence is at carpel initiation stage and the pollen mother cell is at the tetrad stage; the pollen grains mature a nd become functional between June and August of the following year. An thesis occurs from July to September. When plants with inflorescences at carpel differention stage were moved to a growth chamber kept at 10 degrees, 15 degrees, 23 degrees or 30 degrees C, plants transferred t o 23 degrees C: chamber developed flower buds most rapidly and reached the pollen formation stage 4 months later and bloomed after 20 days. Plants kept at the other temperature regimes had fewer inflorescences and flowered later. In plants kept continuously at 23 degrees C from O ctober, the first inflorescence flowered in March of the following yea r. During the growing period for about 13 months, these plants produce d 4.7 flowering inflorescences and initiated 5.1 inflorescences by rep eated sympodial branching. In a commercial forcing trial, plants kept at a min. 20 degrees C from early March flowered in May, 2 months earl ier than the natural flowering time.