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Conclusion
A solitary Entada genet introduced in a research campus
has provided an opportunity to observe new morphological
features in a giant liana (Table 1), raising questions and
ideas on the ecology of the lianas and the biomechanics
of lianoid forms (Table 2).
Table 1 : Summary of salient characters of Entada pursaetha
Observation |
Phenomenon implied |
Seeds required scarification and incubation in pond water for germination |
Mechanical dormancy |
Free-standing upright trunk formed by conjoining of basally sprouted branches. |
Circumnutation of coppices and
thigmomorphogenesis |
Anticlockwise twists throughout mature plant body |
Morphological plasticity |
Branches lean on support trees. |
Discrimination of living support? |
Navigation towards canopy of support trees across large gaps by leafless aerial stolons (remote sensing). |
Perception of chemical cues |
Time taken by genet to spread canopy on neighboring trees <17 yr. |
Rapid growth |
Aerial stolons produce foliage following contact and infiltration into support trees |
Thigmomorphogenesis. |
Infrequent fruiting despite profuse flowering. |
Dependency on a pollinator? |
Pod.>2 feet, seeds large |
High photosynthetic rate, large maternal investment |
Terminal leaflet modifies into tendril |
Interception of light filtering through canopy and response to quantity and quality of light |
Maintained greenness and spread over 1.6 ha despite seasonal drought |
Deep root system, high root pressure |
Table 2 : Research problems for which an introduced Entada can be especially valuable
Research area |
Description |
Biological species invasion |
Tracking the timetable, speed for navigation of aerial stolons towards support trees, Navigation of aerial stolons- evidence for chemical cues. |
Plant biomechanics |
Measurement and comparison of root pressure, transpiration rate, ascent of water to canopy, causes of anticlockwise twists and helical geometry and flexural rigidity of stems, xylem architecture and water transport, and correlation of anatomical parameters of different stem types with structural bending modulus. Reasons for the formation of “screw” type reaction wood (Fig. 2). |
Plant morphogenesis |
Mechanoperception of support trees and differentiation of foliage, germination of seeds, seedling morphology, and role of circumnutation behaviour in seedling for construction of self-supporting trunk. |
Plant physiology, Horticulture |
Rooting of ramets, growth rate and response to light, estimation of compensation point. |
Plant population genetics |
DNA analysis for differentiation of ramets versus genets. |
Microbiology |
Benefit from nitrogen-fixing ability. Possible benefit to trellises from symbiotic nitrogen-fixing ability of leguminous liana. |
Plant Reproductive Biology |
Causes of irregular fruit set, quantitization of viable seeds produced/individual. |
Ecophysiology |
Mechanisms in photosynthetic acclimation to light changes in canopy because of density of foliage; determination of compensation point. |
Plant ecology |
Periodicity in formation of navigating aerial stolons, the time table of their development and speed of extension; the estimation of life-span, comparative analyses of inorganic nutrients (N,P, K, Ca, Mg) in soils in campus and in wetlands (natural habitat) |
Some of the lead questions
that have arisen from its regular observations are: (1)
How did the liana construct the self-supporting trunk? (2)
How does the liana sense availability of support tree from
distance? (3) How do the aerial, cable-like stolons navigate
precisely for infiltrating into the tree canopy? (4)
How does the liana apply force to pull down a support
(bamboo)? (5) What mechanisms liana uses to perceive
and avoid an inadequate support in its trajectory? (6)
How might have the liana growth habit evolved? (7)
What is the lifespan of liana? (The general belief being
that lianas have a long life-span). (8) Does Entada
require a living tree for support?
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