Correlation of vegetative anatomy to the epiphytic habit of Grammatophylum scriptum (L.) Bl. var. scriptum, an indigenous Philippine orchid.

Date

4-2006

Degree

Bachelor of Science in Biology

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Annalee S Hadsall

Abstract

The morpho-anatomy of the root, stem and leaf of Grammatophylum scriptum (L.) Bl. var. scriptum was studied for better understanding of its epiphytic nature and ecological adaptation. Grammatophylum scriptum (I..) RI. vat. scriptum was observed to possess thick spongy velamen that ensures absorption of almost all available water, especially during dry conditions. Likewise, it also affords protection to the innermost tissues. Large parenchymatous cells that function for storing water was found in the cortex.These cells possess multi-spiral thickenings that resemble the hyaline cells of the Sphagnum moss. The parenchymatous cells of the pith allows water storage absorbed by the velamen. The stem of Grammatophylum scriptum (L.) I3l. var. scriptum was observed to be modified into thick, fleshy organ called a pseudobulb. Anatomically, the pseudobulb possesses large, water-storing cells, an adaptation for conserving water. In addition, the number of leaves maintained in the pseudobulb for this species was lesser compared with the other terrestrial orchids. This reduced number of leaves is related to the absence of shoot observed widely in epiphytic orchids. Both leaf and stem epidermis have thick cuticle to reduce evapo-transpiration. Mechanical support is provided by the presence of collenchyma cells in the leaf. Below and above the leaf veins were collenchymatous bundle caps. The old mature roots were transformed into trash basket that gathers humus and other debris, and stabilizes the spatial orientation of the orchid on branches and trunks of trees.

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

Thesis

Document Type

Thesis

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