Physiological characterisation of aquatic traps in the epiphytic carnivorous plant Utricularia humboldtii
The suction traps of aquatic Utricularia species are discoid bladders, 1-6 mm long, with their lumen isolated by a mobile trapdoor from the ambient medium. Water is pumped out of the traps to maintain the negative pressure in the reset traps. When a prey animal touches the sensory hairs on the trapd...
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Veröffentlicht in: | Botanica Serbica 2024-01, Vol.48 (2), p.309-314 |
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Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | The suction traps of aquatic Utricularia species are discoid bladders, 1-6 mm
long, with their lumen isolated by a mobile trapdoor from the ambient
medium. Water is pumped out of the traps to maintain the negative pressure
in the reset traps. When a prey animal touches the sensory hairs on the
trapdoor it opens, the ambient water along with the prey is sucked inside
and the trapdoor is closed again. Utricularia humboldtii is a robust,
semiaquatic-epiphytic or terrestrial species from the generic section
Orchidioides from South America. The efficiency of its aquatic traps was
measured based on trap firing and resetting rates as well as changes in trap
thickness due to both mechanically stimulated and spontaneous firings using
an electronic sensor. The U. humboldtii traps exhibited relatively low
firing and resetting rates. These values are 2 to 20 times lower than those
in other aquatic Utricularia species reported in the literature. These
results together with the low aerobic respiration rate of sliced traps
indicate that the less efficient aquatic traps in U. humboldtii are
specialised for catching fine prey items in bromeliad water tanks. A marked
lag-period in trap resetting was found to occur during the first 30 min
after firing, contradicting the accepted concept of continuous water
pumping. Spontaneous trap firings were also observed with the same magnitude
as that in stimulated firings. This implies that spontaneous firings occur
consistently in all the tested aquatic Utricularia species. However,
although they relate to the continuous water pumping mechanism of the traps,
their physiological importance has not been fully elucidated. |
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ISSN: | 1821-2158 1821-2638 |
DOI: | 10.2298/BOTSERB2402309A |