Developmental and Structural Section
Liu, Shih-Hui , Yang, Yuen-Po .
The development of flower, fruit, and root in Trapa natans.
The development of flower, fruit, and submerged leaves in Trapa natans L. (Lythraceae) had been studied by scanning electron microscopy and paraffin method.The flowers of T. natans are solitary, axillary, bisymmetry, and tetramerous. The sepals and androecium differentiated in pair. At first, two lateral sepal primordia initiate on the border of floral primordium, then the adaxial and abaxial sepal primordia initiated. They grow upword, closed on tip, and fused at base to form calyx cup. In the sunken floral apex, the antisepalous adaxial and abaxial androecium primordia developed at base of calyx cup, and two antisepalous lateral androecium primordia arise next. And then, four alternisepalous petal primordia appeared. finally, two carpel primordia originated in the median of the floral primordium and fused to become syncarpous gynoecium.To comply with growing flower, the multi-cell uni-sericeous hairs form outside of sepals, and the sepals connected each other at flank. Petal primordia enlarge and becomed the thin, transparent, oblanceolate petals. The androecium primordia grew to become radial basifixed anther first, then dorsifixed anther, and versatile finally. The mature anthers had four pollen sacs, and were logitudinally dehiscent. The gynoecium enlarged and formed upword plicate on the surface of sub-inferior ovary. There were many finger-like protrusions on the plicate. The base of calyx cup inside and the tip of the finger-like protrusions had stomata which are similar to those on upper epidermis of floating leaves.After blooming, the adaxial and abaxial sepals, androeium, and petals fall off. In the population, individuals without barbed or horn could be found. This situation depended on the destruction levels of lateral sepals.The dissected submerged leaves differentiated form in the stele of stem where the leaf trace is located. The lateral branches of the so-called submerged leaves developed in the stele of the rachis. The stele of the dissected leaves is actinostelic protostele. These evidences indicated the so-called submerged leaves are truly submerged adventition roots.
Log in to add this item to your schedule
1 - Saint Louis University, Biology, 3507 Lacleded Avenue, St. Louis, MO, 63103, US
2 - Da-Yeh University, Bioresources, 168 University Road, Dacun , Changhua, 51591, Taiwan, ROC
Presentation Type: Poster:Posters for Sections
Location: Battelle South/Convention Center
Date: Monday, July 9th, 2012
Time: 5:30 PM