A Note on the Effect of Handling on the Respiration of PotatoesAuthor(s): John BarkerSource: New Phytologist, Vol. 34, No. 5 (Dec. 4, 1935), pp. 407-408Published by: Wiley on behalf of the New Phytologist TrustStable URL: http://www.jstor.org/stable/2428282 .

Accessed: 17/06/2014 05:28

Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at .http://www.jstor.org/page/info/about/policies/terms.jsp

.JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range ofcontent in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new formsof scholarship. For more information about JSTOR, please contact support@jstor.org.

.

Wiley and New Phytologist Trust are collaborating with JSTOR to digitize, preserve and extend access to NewPhytologist.

http://www.jstor.org

This content downloaded from 188.72.126.55 on Tue, 17 Jun 2014 05:28:25 AMAll use subject to JSTOR Terms and Conditions

[407]

A NOTE ON THE EFFECT OF HANDLING ON THE RESPIRATION OF POTATOES

BY JOHN BARKER

Low Temperature Research Station, Cambridge

(With i figure in the text)

POTATO tubers which possess a firm turgid flesh can be subjected, without serious disturbance of their respiration, to the handling

necessary in weighing and placing in a respiration container. Follow- ing such treatment, the respiration usually falls slightly initially, but provided the handling has been careful, no further decrease in respiration occurs after 2-3 days in the container. If, however, the potatoes are soft owing to loss of water and senescence, the effect of handling is marked.

1.0~I

I'0

4-.) o F s --. __'___

Gently squeezed

C . 0 10 20 30

Days

Fig. i. Effect of handling on respiration of soft old potato.

A soft shrivelled potato, which had been kept at I5' C. for I5 months and had lost roughly 50 per cent. of its original weight, was examined by gentle pressure with the fingers to ascertain the con- dition of the flesh, weighed and placed in a respiration container.

This content downloaded from 188.72.126.55 on Tue, 17 Jun 2014 05:28:25 AMAll use subject to JSTOR Terms and Conditions

408 JOHN BARKER

No measurements of the respiration were made for 2 days, but after this period a fall in respiration of about 2o per cent. was observed (Fig. i), a level being reached in 8-io days. After II days the potato was removed from the container, gently squeezed and at once re- placed. This treatment produced an immediate increase of about 30 per cent. in the respiration (Fig. i), and the rate did not return to the initial value for some IO days.

The magnitude of the disturbance of the respiration caused by handling is presumably related to the extent of the compression or deformation of the tissue which occurs. In contrast with firm turgid- fleshed potatoes, the potato used in the above experiment was so soft that even slight squeezing caused a visible compression. On the other hand, the respiration of such soft potatoes was but little disturbed if compression during handling was avoided.

This content downloaded from 188.72.126.55 on Tue, 17 Jun 2014 05:28:25 AMAll use subject to JSTOR Terms and Conditions