Peninsula enterprise. [volume] (Accomac, Va.) 1881-1965, 1905-11-25
SENSE ORGANS IN PLANTS.
Light Perceiving Leaves That Ha'o
Ewes and Eyelashes.


DR. G. Haberlandt, professor Of bot
anv in the University Of Gratz, cele-
hrated for his revelations on the sense
organs In plants, is their champion
who tells the world that having eyes,
they see.
The first question for DR.. Haberlandt
TO solve was what part Of the leaf was
,ensitive to light. By covering the
leaf with black paper he shows thst
The principal and most delicate sensl-
tiyeness resides in the blade, although
@ coarser and secondary sensitiyeness
10 the incident light is found IN inc
stalk.
This meant that the blade Of the lear
must contain the eyes, If eyes there be.
ANYTHING corresponding to an organ
for sight he reasoned, would be on
the surface. So he looked for the
ocelli, as he terms the light perceiying
organs Of plants, in the epidermis COW
ering the upper surface Of the lear.
1t can also be seen, as the botan-
ical oculist discovered, that the rela-
ton OF the spot of light to the sur
rounding part, which is more or less
dark. changes when the light falls
obliduely. So when q leaf Is illuminat-
ed obliquely he considers that 1t Is
stimulated to curve by the fact that
the spots Of light are not central In the
cells, and the curving ceases when tho
brightest illumination is once more In
the center. So the plasmic membrane
Of this inner wall of each cell in the
epidermls becomes the retina Of the
eye or in scientific phrase, has q
quasi retlnal function by which the
leaf is believed to orientate itself In re-
gard to light"
Proceeding, DR.. Haberlandt exam
ined the eye and found that 1t was
good, well fitted to concentrate light. 1t
is commonly lenslike in form, the outer
wall being convex, the inner wall ell
ther plain or curved.
Plants have not only eyes, but eye
lashes. The topaeolum, the handsome
cousin of the horid fuchsia, is one OF
the proud plants that can vaunt them
selves on the luxurious comeliness OF
fine lashes. The leaves Of this plant are
unwettable, and when immersed re-
main coated with silvery mantle OF
air. The waxy layer which gives this
quality may be removed by painting
the surface with diluted alcohol with
out injury to the leaves. The result OF
immersion Is that normal leaves, pro-
tected by layer Of air, react normal
ly TO oblique illuminations-that Is,
they see, whereas the wettable leaves
whose waxy bloom has been removed
have lost their eyesight, their power OF
reacting, says the Chicago Tribune.
Ia all~Dr. Haberlandts experiments
he always has found his ocelli (eyes) or
the upper and not the lower surface oi
> leaves. And he also found them tend
j ing to occur especially near the edge:
of leaves Just in those regions where
D the amount Of movement correspond
ing to curvature through a given angle
is greatest.
j The position of the eyes is In th'
L most advantageous position possible
, for the eyes to receive the rays OF th'
sun and yet be shielded from exposure
: The eyelashes droop directly over tn
eye itself when showers come, and tn
{ leaf turns slightly so that the eyslashe
form a perfect protection. Also, II tn
: leaf is exposed to too great heat fron
the sun the lashes droop again. shad
ing them.
6 The eyes Of leaves vary greatly, &C
l. cordlng to the professor, in diferen
u plants and trees, and he believes tn
sense Of sight much more highly deve
1t oped in the rapid growing and tropics
c plants than in others.-New Yor
World