(1

1877/(Used) Common Bean— Movement of plumule under Ground

Plumule arched at very early age. (Cots. hypogean)— shown The arching as Hab; remarks importance of the arc— lifts ground in a crust. (a) Back

Dec 18th Uncovered seed deepish in ground & tied tip of seedling plumule which was not yet out of seeds(?) to basal part & then filled up hollow with crumbly earth, leaving leaving minute conical hollow from glass filament, which was fixed to basal part of basal half of hypocot. plumule stem. See diagram I for movement on 18 from 11° 55 12° to 10° 44'.

From position of seed this was due to going curving back from tip of plumule & from the bean itself of basal half of hypocot stem & the line is zig-zag showing tendency to circumnutation. (All this important.) Changed course a little during night.—)

(Next day (19th) filament made, I believe, 2 small circles, but tracing was not magnified enough; so at 3° P.m changed everything & fixed on glass filament (The tip of arc of plumule was now on level with ground) & began new Tracing II: ca zig-zag course, in direction showing that basal half of stem was again rising & between 7° 20' P.m & 10° 50' made a small circle. Dotted line shows course during night, & ( From 7° a.m to 8° 7' on the 20th moved to left. Glass filament was then broken & new one affixed by Frank & was affixed rather high up, & at 9° new tracing begun, but whether general direction was was any longer the same I know [not] & but the tracing shows general course movement of travelling with some zigzag. The next morning the end of plumule was free & had broken loose.

[1v]

(a)

A seed behaves like a man resting on hands & feet Knee on ground with over whom a mass of earth has fallen, he pushes bodily upwards, but wriggles a little from side to side to free himself—, then pushing backwards he raised the upper end of his body which arisen to upper end of plumule or cotyledons; his feet still remaining firmly embedded in soil—

 

(2

Common Bean

(Used)

Dec. 20th Another seedling — uncovered bean rather deeply buried, fixed glass filament to basal half of arched plumule & tied tip not yet out of seed(?) firmly to basal half — then filled up hollow with crumbly earth leaving little opening round filament — Kept in dark & traced on horizontal glass— Tracing magnified 21 6/10 times without considering the increase from glass-filament. See Diagram III which gives, movement during 3 days. The main movement from the seed & tip of plumule, with some zig-zag & even one approach to an ellipse on the 21st. The movement was confined almost to one direction, owing, as I believe, to the glass filament being attached close to base of plumule.— All movement in this part, except a most minute nutation, on the third night.—

(Dec. 24 & 25' Beans laid flat on soil (damp air) the pla root first emerges & by geotropism penetrates ground & holds seed firmly; then plumule emerges bent in arc with tip held for some time by coat of seed— The arc lies at first in same horizontal plane with seed, then whole arc through apogeotropism bends at right angles upwards & from growth along concave side the tip & base separate. This great movement masks revolving nutation which certainly exists from zig-zag course of tied plumule. I am not sure whether with untied plumule the basal part moves backwards— I may have mistaken the upwards

(over)

[2v]

movement of whole arc — The tip of plumule is directed in any position with respect to seed— We have seen that nu nutation soon ceases at base of plumule.

(3

Dec. 26-30th Common Bean

a Bean with end of plumule at right ∠ to basal part which stood vertically had glass-filament fixed to basal part, & movements traced on Horizontal glass in darkness. Tracing M. magnified 20 2/10 times.

Tracing M. observed from 9° a.m. on 26th to 11° a.m. 28th, when filament became loose. & after

On the 27th at 10' a.m. the upper part of plumule above right ∠ with basal part. The basal part of plumule had grown & filament on the 28th attached about 1/2 way up the basal half & .4 above upper surface of the bean itself. Therefore this part of plumule which tracing shows to have nutated so much, though irregularly, would (if the bean had been sown) had been under ground.

I have said at 11° on the 28th the filament came loose, though I did not discover this for some time & the line traced was travelled in straight line to right & has not of course been copied. At 8° 40' Dec. 28 P.m I fixed filament to lowermost scale, I suppose representing a bractea on upper part of vertical basal half of plumule which was now much elongated & wd have projected out of ground; but the upper part of plumule still formed an very open angle with lower part & the leaf was at all expanded. The movement of this upper part of Plumule, traced in same manner & magnified

(4

Common Bean (Used)

24 [+] 4 [=] 38

to same degree are shown in Tracing N. from 8° 40' P.m Dec. 28th to 10° 50' to 8° 40 m. to 29th a.m on Dec. 30th— The broken line in all cases shows course during night. This tracing might have been joined on with break to the one above

We have here in p. 3 & 4 fine evidence of nutation in plumule before leave ground & afterwards, & before the whole has become erect & straight; but the first observation was made after the arched plumule had bent up from horizontal into vertical position. At end of observation the basal part of plumule beneath where first scale arose was 1 3/4 inch above upper surface of bean itself.

As I thought that possibly basal part of plumule wd move against pressure I fixed slip of card lightly then pressing, but they produced no effect.