DEVELOPMENTAL MORPHOLOGY OF THE DETERMINATE BRANCH IN EUPHORBIA PULCHERRIMA WILLD EX KLOTZSCH (KASTUBA)

• Main Author: Hasan, Yulmizar
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/9713
• Institution: Institut Teknologi Bandung

Developmental morphology of the determinate branch in Euphorbia putcherrima Willd. ex Klotzsch. had been investigated. The morphological aspect was studied for 9 individual axes. To study the anatomical development, various developmental stages of a branching bud fixed in Craf III C Chromic acid, acatic acid, formaldehyde) followed by dehydration in Johansen's mixture and then infiltration and embeded in paraffin. Serial sections were cut at 10 pm and stained with Haematoxylin Delafield. The overall architecture conforms with Leeuwenberg's model and the branches are modules. A module consists of a sympodial branching set where apical activity becomes limited due to the transformation of the apical meristem into an inflorescence which is a cyathium. Three branches then developed each originating from an axillary bud subtended by three sequential leaf primordia immediately below the apical meristem. Each of the newly formed branch branches in a limilar manner but produce only two branches. This pattern will be repeated two or three more times. Each branch is only one inter node long. Up till this stage the apical meristem always produces an imperfect inflorescence. After the last order of branching each resulting branch growsinto a long axis comprising many nodes at the end of which reproductive branches will be formed during the next growth periode. The reproductive branches are formed in a similar manner as the vegetative ones, up till the second order of branching and are accompanied by a fully developed inflorescences. Afterwards the branch length will be still be one node long, but very much shortened and one of the two branches of each branching order does not develop at all. This behaviour allows a grouping of the inflorescence at the outer and upper margin of the tree crown, being more conspicuous because of the red coloration of the leaves in this region. A branching terminal bud will show increase in diameter caused first by widening of the apical mer i stem during the formation of the inflorescence and afterwards by the development of the first order of branching producing three developing buds respectively in the axil of three leaf primordia. This branching pattern is followed in the development of higher order branches. At the vegetative branching the cyathium developed into an i nvol ucr um with incomplete staminate and pistillate flowers. At the reproductive branches staminate and pistillate flowers in the cyathium are fully developed and mature. After flowering and fruiting reproductive branches will dry out up till half the length of the subtending stem. From dormant axillary buds below the drying portion new axes will develop repeating the vegetative branching during the following growth <br />