TY  - JOUR
T1  - Pseudobulb Water Storage and Leaf Morphology: Key Adaptations of Wayanad's Epiphytic Orchids to Summer Drought
AU - Sabu, V.U. AU - Paulose, Jincy 
JO  - Botany Research Journal
VL  - 18
IS  - 1
SP  - 1
EP  - 5
PY  - 2025
DA  - 2001/08/19
SN  - 1995-4751
DO  - makrjms.2025.1.5
UR  - https://makhillpublications.co/view-article.php?doi=makrjms.2025.1.5
KW  - Epiphytic orchids
KW  - pseudobulbs
KW  - leaf morphology
KW  - drought adaptation
KW  - wayanad
KW  - western ghats
KW  - orchid conservation
KW  - velamen
KW  - cuticle
KW  - microclimate resilience
KW  - climate change
KW  - canopy ecology
AB  - The Western Ghats of India, a UNESCO‐recognized global biodiversity
hotspot, harbor an extraordinary diversity of orchid species, many of
which exhibit specialized adaptations to survive the region's pronounced
dry seasons. Among these, epiphytic orchids‐plants that grow upon other
trees without rooting in soil‐are particularly vulnerable to water scarcity
due to their exposure to variable canopy microclimates. This three‐year
study (2023‐2025) focused on understanding the drought resilience
mechanisms of epiphytic orchids in the montane forests of Wayanad,
Kerala, with particular emphasis on two key structural features:
pseudobulb water storage and leaf morphological traits. We selected six
representative epiphytic orchid species found across moist deciduous,
semi‐evergreen and montane evergreen forests, spanning altitudes of
800‐1400 meters. Detailed field surveys, physiological assessments
(including stomatal conductance, chlorophyll fluorescence and relative
water content) and anatomical analyses (pseudobulb structure, velamen
thickness, cuticle development) were conducted seasonally. Controlled
drought simulations in polyhouse environments further validated field
findings. Our results demonstrate that orchids possessing larger,
succulent pseudobulbs and thick, waxy leaves exhibited superior drought
tolerance. These species retained water more effectively, maintained
higher photosynthetic performance under stress, and exhibited slower
rates of dehydration. Anatomically, dense velamen layers on roots and
thickened cuticular surfaces on leaves played crucial roles in limiting
water loss. Statistical analyses revealed strong positive correlations
between pseudobulb volume, leaf thickness and drought performance
indicators. Orchids in shaded canopy microhabitats had higher survival
rates, emphasizing the significance of microclimate buffering. The study
provides the first long‐term, integrative dataset highlighting the interplay
between structural adaptations and drought resistance in South Indian
epiphytic orchids. It offers vital insights for orchid conservation strategies
under shifting climate regimes. Protecting forest canopy integrity and
conserving drought‐resilient orchid species can enhance the ecological
stability of these sensitive montane systems.
ER  -