Agriculture Reference
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Fig. 17.1. a
Potential prey nears a
Dionaea muscipula
(Venus' flytrap).
b
Open
Drosera
(sundew) leaf before and after touch stimulation.
c
Utricularia inflata
(bladderwort) side
view with tentacles visible at right near trap door. The doubly compound leaves of
Mimosa
pudica
(sensitive plant)
d
open before stimulation and
e
closed after stimulation.
f
Repetitive
touch stimulation leads to a delay in flowering and an inhibition of inflorescence elongation
in
Arabidopsis
.Theplantsonthe
right
were touched twice daily; the plants on the
left
are
untreated controls. (Reproduced with permission of the New Phytologist Trust; Braam 2005)
detecting a strand of human hair weighing less than a microgram and yet
rain droplets have little effect in activating the movements.
The trap of the bladderwort (
Utricularia
)mayoperatewithsimilar
mechanisms described recently for Venus' flytrap (Forterre et al. 2005).
This aquatic rootless plant uses a thin-walled hollow sac and a watertight
trapdoor as its prison and digestion chamber (Fig. 17.1c) (Lloyd 1942). The
outer walls are curved inward, pulled perhaps by the negative hydrostatic
pressure inside the bladder. Touch-sensitive appendages extend out near
the trapdoor. When these triggers sense touch, by waterfleas or other small
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