143 C[INNL\G1IAM ON PLÜCTITAXIOMS IN TUBGESCEMCE.
thorough appHcatiim of tlie points of Jieoted forceps to points in tlie course of mature axes was followed
in every case by an entire absence of any movements in any leaves eilJier In tbe centripetal or the
centrifugal direction. This experiment clearly proves that no mere fluctuations iu pressure in the liquid
contained in Jlabfirlandt's Reizleitencle system" are effloieut to occasion any propagation of movemeuts.
The local application of lieat must here, a? usual, have given rise to an elevation of pressure
Avithin the liquid contained in the system of sieve-tubes, and as usual tliis elevation must have
been propagated in both directions, and yet t o movements -whatever took place either centripetally or
oeiitrifugally. The absence of the ocuurrenco of any centTifugally propagated movemoats under such
circumstances is readily explicable if we regard the centrifugal propagation which is ordinarily present as
the result of obstruction to the ascent of water along the water-conducting system incident on the
great gaseous expansion caused by the local applioatiou of heat. Under tbe circumstances prevailing at
the time of th» experiment not only must the entire water-conducting system have contained an oLess
of water, but transpiratory loss of water must bave been practically absent. But this being so, there
is no reason why a temporary ohstructiou or arrest in the passiJge of wat«r along the water-con ducting
system should have glveu rise to the occurrence of any centrifugal piopogalion of movement; for, with
minimal transpiratory loss aud the presence of large quantities of reserve-water within the water-conducting
system, there was no immediate demand for continuous root-supply in order fully to meet tiio
demands of the motor organs, and the temporary obstructive effect of ihe gaseous cxpansioQ mi^'ht well
have entirely disappeared ere such a demand arose. °
Espeiumest X X V n i . - J u l y 24th, 8 a.m. Almospkeric iempcruture 78-Ù°F. Humidily 94 per cent.
The morning irns cloudy. Very !mv!/ rainfall had occurred shortly Icfore the period of crperlmoit ami everything
wad drcnchcd iciih moi '••iiwj'pi^—Searing pt^nits in tlie course of mature i
slow impevfaot action ia the first leaf beyon.i the iujured point.
! foDowed only by
GROUP D.-HUAIIDITY MODERATK OK lOW.
a.—Residts foUoiving amputation of iermmal pinnules of dktal fimicc, .o.
tips »/ azes.
1. Effects following the ampiiiation of Hps of pinnuUt.
amputation of
Expfhimest XSIX.—Complete elevafio
of (he primary petiole of the injured lesf.
1 of all the piunuIes of all the pinnoe and deep i
Exi-euimest XXX.-Complete action throughout the whole of the injured leaf.
Experiment XXXI.-Complete action throughout the whole of the injured leaf and depression of
the jinmary peljole of the one next above it on the axis.
Expehimknt XXXH.—Complete action throughout the whole of.the injured leaf
Experimríít X X X I i r . - C o m p í e t e action throughout the whole of the injured leaf
Experiment X X X I Y - C o m p l e t e acion throughout the whole of the injured leaf; almost complete
actum throughout the whole of the leaf next above it on the asís.
Expebimkmt XXXV.—Complete action in the injured kaf and
the axis.
Expehdient XXXVI.—Complete action ii
nest below and the cue nest above it on the £
the one next above it <
1 the injured leaf, followed by complete action in the o:
Expehimest XXXVIL—Complete action in the injured leaf, followed by complete action in the
one next below and the one nest above it on the axis.
Experiment XX XVI11.-Complete action throughout the whole of the injured leaf
Expkrimest XXXIX.-Complete action throughout tbe whole of the injured leaf.
Experiment XL.-Complete action throughout the whole of the injured leaf; complete action in
tbe first lea above ,t on the a.xis; depression of the primary petiole and partial elevation of the
pinnules ol the thud loaf abovo the injured one.
APPENDICES. 143
3. Effcch following amptdation of tips of axis.
Experimest XLL—Action in the first four leaves beneath the tip, aud action in five other
leaves situated at some distance lower iu the course of the same shoot.
Experimext XLII.—Centripetal propagation of movement to all the leaves on the same shoot
Exi'EBImest XLIII.—Centiipetal propagation of movement to all the leaves on the same shoot.
BxPEniMENT XLTV.—Centripetal propagation of movemeuts to the nine leaves situated immediately
beneath the tip along the coiurse of the same shoot.
Experiwest XLV.—Centrii>etal propagation of movement to all the leaves on Ilio same shoot.
h.—Results following ihe application of flame ia ihe Hps of lerminal pinnules of distal pinnce.
1. Plants rooted in the open ground.
Experiment XLVI.—Complete action throughout the whole of the injured leaf and the one next
above it on tbe axis.
Experimekt XL vii.—Complete aotion throughout the whole of the injured leaf and the one nost
abovo it on the axis.
Experiment XLVIII.—Complete action throughout the injured leaf and depression of the primory
petiole of the one next below it on tbe axis.
Experiment XLIX.—Completo action throughout the injured leaf ; complete action in one leaf
below and in two above it on the same axis.
ÉxrEHiMENT L,—Complete action in the injured leaf and in the two next above it on the axis.
ExpiiRiMEST LL—Complete action throughout the injured leaf; incomplete action in two above and
one below it on the same axis.
the injured leaf; followed by complote action in all the
n the injured leaf, followed by complete action throughout all
1 all the
2. Pot-plants.
I n the case of pot-plants the effects following the application of flamo to the tips of pinnules are
much more extensively propagated, owing, no doubt, to their moro limited root-supply.
Experimest LII.—Complete actii.n in the injured leaf; completo action in all the leaves above it
aud in one below it on the same axis.
Experimkkt LIII.—Complete action i
other leaves over the entire plant.
Experiment LIV.—Completo action i
the leaves on the same axis.
n the injured leaf, followed by complete action
E s p e r i m e s t LV.—Compute aotion i
leaves on the same shoot save the lowest o'
i the iujured leaf and in the thri ! next above it
Experiment LVI.—Complete aciion ii
the axis.
Experiment LVII.—Complete action ia the injured leaf and in nil the others on the same axis.
The following experiment illustrates the influence which difterences iu degree of soil-moisture alone
are capable of exerting on the nature of the phenomena attending the application of flame to the tips
of terminal pinnules of distal pinmo.
Kxperiment LVIII,—iTnne 22nd. Atmospheric Icmperatiire 84-5°P. Ilumidily 77 per e.enf. Two
pot-plants, A and B, were standing side by side in tbe open air and were under precisely the satne
eironmtances, save that the earth in the pot iu wliith A was contained was dry, whilst that in the
pot contaiuicg B was thoroughly moist in consequence of the recent addition of water.
Wheu flamo was applied to the terminal pinnules of leaves of A complete action throughout
the irjnred leaf, followed by the occurrence of movements ia varying numbers of leaves
situated along the coui-se of tho same shoot, occnrred in every instauce; whereas, when simibr trcntmciit
wuB applied to leaves of B, it was followed merely by slow, imperfect elevation of all the
. IloY. Bot. Gaud. C.ílcuti'a Vol. VI.