Strawberry ( Fragaria ananassa )

Abstract

Apices of strawberry plants ('Dunlap,' 'Sparkle,' 'Catskill,' and 'Royal Sovereign') were dissected at intervals between August and November. The structure of the crown and any inflorescence were diagrammed, and records made of crown size and number of leaves. Both the diameter of the crown and the diameter of the bud (enclosed primordia) were correlated with the number of leaves on runner plants. The number of leaf primordia was also correlated with both crown and bud diameters. Growth of the older leaf primordia declined earlier in the fall than did growth of younger primordia. This was evident in lower primordium length ratios as the season progressed. Initiation of an inflorescence was first evident as a raising and enlargement of the apical meristem. Initiation of the primary flower began after the bracts of the inflorescence were evident. Floral initiation is centripetal, the sepals appearing first, followed by petals, stamens' and pistils. The phyllotaxy of the crown continues in the bracts of the main axis of the inflorescence. Branches of the inflorescence usually have two bracts. These were not opposite but were closer together on the side nearest the central axis. This structure was associated with variations in the frequency of flower initiation in the axils on the tertiary and higher order axis. Initiation in the quarternary positions was about eight times more frequent in axillary positions facing the outside of the inflorescence than in those positions oriented toward the center. ARNEY (1953, 1955b) in England found that plants of the 'Royal Sovereign' strawberry normally carried six leaf primordia in the crown. During the wvinter, growth of the younger primordia continued after growth of the oldest primordia had slowed down, resulting in an