Anatomical verification of Thai local classifications of durian (Durio zibethinus Murr.) floral development and vegetative conversion of the buds.

摘要

In the present study, we observed the anatomical processes of durian flower morphogenesis and tied these stages to the accompanying changes in external appearance. Obervations were conducted at a commercial durian orchard in Chanthaburi, eastern Thailand on a 5-year-old 'Monthong' durian tree. Three to 5 buds per tree were collected for each developmental stage. Dormant buds had brown, hard surfaces. At the fish-egg stage, young tissue emerged from the hard surfaces. Some fish-egg stage buds turned into vegetative buds which can be characterized by the elongation of young leaves. At the undifferentiated stage, the growth point was observed in the apex, which broadened and became thicker in the dome stage. The epicalyx then fused and the sepal primordia arose inside the enclosed epicalyx at the sepal formation stage. Sepal formation was followed by petal formation. In the dormant stage, the growing apex was observed within the bud, and floral organogenesis had not yet started. In the early fish-egg stage, although some buds developed into the dome stage, most remained undifferentiated. During the late fish-egg stage, some buds reached the sepal formation stage. Flower buds in the mouse-leg stage showed carpel formation. At the crab-eye stage, more than 80% of the buds showed carpel formation.