RECORD: Darwin, C. R. 1878.11.14-12.04. Beta vulgaris [application of gold beaters skin]. CUL-DAR209.8.33-34. Edited by John van Wyhe (Darwin Online, http://darwin-online.org.uk/)

REVISION HISTORY: Transcribed by Christine Chua and edited by John van Wyhe 7.2022. RN1

NOTE: See record in the Darwin Online manuscript catalogue, enter its Identifier here. Reproduced with permission of the Syndics of Cambridge University Library and William Huxley Darwin. The volumes CUL-DAR209.7-8 contain notes on heliotropism (phototropism) for Darwin's book Movement in plants (1880).


[33]

Nov. 14th 1878 Beta vulgaris — Light. upper 1/2 protected Gold-Beaters skin

Exposed to Paraffin Lamp in dark at 9° 20' a.m. examined Temp of room only 55° F.-56°— 54° at night

Young seedlings with Cots hardly raised to straight line.

Hypocotyl. upper half of 4 covered with gold-beater skin left unpainted

 — — of 7 painted twice with thick Indian ink.—

Examined Nov 15th 7° 30' a.m, having been exposed all this time to Paraffin Lamp.— Plant proves bad for purpose as the hypocotyls do not bend down to very base.— Nevertheless I think 3 of the Blackened ones are have their basal halves a little curved towards light, the other straight, but difficult to compare

The 4 with unpainted skin well curved to light.—

The painted upper half curved in none.—

[34]

Dec. 4th 1878. 2 Pots of Phalaris exposed to Paraffin & 1 of red Cabbage from 7° 40' a.m to 4° 35' P.m & were nearly horizontal— They were then turned up & pot laid on one side & 3 plants in each pot found with cots. vertical by Phal-line. They were observed till 8° 30' P.m.— Three of the 6 inclined outwards i.e. in opposition to gravity as much as 11°, 4° & 6°, some others were more inclined inwards — this was at 6° 30'— afterwards they changed their inclination a little & so they did next morning, & I concluded that they were simply circumnutating.

[in margin:] With cabbage I cd perceive no bending outwards

On the whole I may conclude that in my former observations as evening draws on & plants move from light this is due to apogeotropism acting on circumnutating stems.— I ought to have said that I expected that when light suddenly ceased cots wd have bent in opposite direction owing to tension on illuminated side having ceased & growth not having completed work on convex side, but no evidence of this—

(over)

[34v]

I examined 3 of most bent stems under compound & simple, illuminated from above & below & cd see no vestige of transverse creasing on the rectangularly concave side.

Phalaris. N.B. To make these observations of value I sought to bend mechanically some be straight cotyledon into a rectangle & look at concave side & see if creases can be distinguished.— If pushed by growth on darker convex side, there wd be creases on the concave side.


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Citation: John van Wyhe, ed. 2002-. The Complete Work of Charles Darwin Online. (http://darwin-online.org.uk/)

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