In the previous report, the authors investigated the influence of night temperature, light intensity and fertility of bed soil upon the morphological and physiological development of the tomato flowers and the flower drop.
The present studies were carried out to ascertain the influence of watering, defoliation and application of gibberellin upon the morphological and physiological development of the tomato flowers and the flower drop.
1. Effects of early environmental conditions and cultural treatments on the morphological development and the premature drop of the flowers.
Tomato seedlings (Variety: Fukuju No. 2) were grown and supplied 50-100ml, 300ml and 500ml irrigation water per pot every day. The less became the water supply, the smaller became the flowers, with smaller sepals, petals, anthers and ovaries. The water supply, however, did not influence the flower drop.
The mature leaves of tomato seedlings were removed alternately or successively at the nodes from 1 to 8 when they reached to about 10cm in length. Tomato seedlings were sprayed with solution of gibberellin A₃ at 100ppm when the cotyledon expanded fully and repeated eight times at 5-day-intervals. The defoliation of mature leaves and/or the application of gibberellin A₃ retarded the morphological development of flowers and hence resulted in forming smaller flowers with smaller sepals, petals, ovaries and especially smaller anthers and heavy flower drop ensued.
2. Relations between the morphological and physiological development of the tomato flowers.
The seedlings grown under the less water supply contained the higher levels of nitrogenous constituents and the lower levels of carbohydrates in the flowers, stems and leaves and had smaller flowers.
The seedlings, defoliated the mature leaves, and/or supplied with gibberellin A₃ contained the lower levels of total sugars, starch and polysaccharides in the flowers, stems and leaves. The seedlings had smaller flowers and especially smaller anthers. with mostly abortive pollens and lower auxin content.
3. Relations between the flower drop and the morphological and physiological development of the flowers.
The flower drop of the seedlings defoliated the mature leaves and/or supplied gibberellin A₃ were not effectively controlled by the auxin application at full bloom.
The results of the previous and present experiments show that the deficiency of carbohydrates and/or nitrogenous constituents in the flowers, stems and leaves increased the flower drop, however the flower drop were modified by the auxin application at full bloom, and the flower drop of the seedlings grown at the high night temperature and/or under the low light intensity were effectively controlled by the auxin application at full bloom.