ISHS Acta Horticulturae 179: V International Symposium on Growth Regulators in Fruit Production
FLORAL TUBE AND STYLE ABSCISSION IN PRUNUS |
| Author: | Roy K. Simons |
| Abstract:
Abscission of the reproductive floral organs in Prunus occurs sequentially and at a very rapid rate. Growth regulators have not been successful to control or to promote abscission. The anatomical changes occur within the plant before it is possible to observe them macroscopically. Morphological characteristics of ten stages in the peach flower have been described as developmental reference points for the timing of production practices. Other studies include Montmorency cherry (Prunus cerasus), apricot (Prunus armeniaca L.), cherry (Prunus avium L.), and plum (Prunus domestica L.).. The adaxial and abaxial surfaces of the floral tube of Prunus persica L. are characterized by distinctly different epidermal morphology. Stomata on the adaxial surface are dispersed among trichomes from the basal to the distal portions adjacent to the filament base, and are partially covered with epicuticular deposits. The abaxial surface is devoid of pubescence and is densely cellular with stomata sparsely dispersed over the entire surface. Abscission occurs in the various plant parts sequentially. Anther filaments begin to abscise, followed by stigma dessication. As the style abscises, progressive development from the stigma to the stylar base occurs in at least three different stages following pubescence abscission on the style. Floral tube abscission follows this progression in different stages from the distal to the proximal portion of the floral tube and develops in a sigmoid curve originating on the adaxial side. Sequential bud scale abscission in peach shows progressive development occurring in the outer bud scales prior to dormancy. Redhaven and Reliance (cultivars having tolerance to frost) had at bloom longer fruit peduncles covered with numerous bud scales that partially protected the floral tube and receptacle base. Abscission ceased on the bud-scale tips in some cultivars, but in others this development progressed at a slower rate throughout the dormant season. In contrast to peach, plums were characterized as having six different stages, extending from anthesis through style abscission. Eight stages have been established for cherries, ten for peaches and apricots. Abscission development of the plum was characterized by loss of chlorophyll pigmentation, as contrasted to dehiscing pubescence and shrivelling in the peach. | |
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