176 Drying and Wilting of Plants [374 
INCIPIENT DRYING AND TEMPORARY AND PERMANENT 
WILTING OF PLANTS, AS RELATED TO EXTERNAL 
AND INTERNAL CONDITIONS 
By Burrow E. Livineston 
It has been shown by Renner,’ by Livingston and Brown,” 
by Lloyd* and by Edith B. Shreve,* that the water content 
of plant leaves, twigs, etc., is markedly lower after a period 
of relatively great transpiration (as in the middle of the 
day) than it is after a period of very small transpiration (as 
in the latter part of the night). The moisture content of 
leaves, for instance, was found (Livingston and Brown) to 
exhibit a diurnal march, the rate of water loss from these 
organs during the forenoon hours (or even during the whole 
period of sunshine) being greater than their rate of water 
intake, while the rate of foliar intake of water during the 
night hours was greater than the rate of water loss. The phe- 
nomenon indicated by diminished water content in the day- 
time was called incipient drying by Livingston and Brown. 
Renner employed the term sétigungsdefizit to denote the 
similar phenomenon encountered in his experiments. The 
experimentation of all but Renner, of the authors mentioned 
*Renner, O., “ Experimentelle Beitriige zur Kenntnis der Wasser- 
bewegung.” Flora 103: 171-247. 1911. Idem., “ Versuche zur Me- 
chanik der Wasserversorgung. I. Der Druck in den Leitungsbahnen 
von Freilandpflanzen. Ber. Deutsch. Bot. Ges. 30: 576-580. 1912. 
* Livingston, B. E., and Brown, W. H., “Relation of the daily 
march of transpiration to variations in the water content of foliage 
leaves.” Bot. Gag. 53: 309-330. 1912. 
* Lloyd, F. E., “The relation of transpiration and stomatal move- 
ments to the water content of the leaves of Fonquieria splendens.” 
Plant World 15: 1-14. 1912. Idem., “Leaf water and stomatal 
movement in Gossypium, and a method of direct visual observation 
of stomata in situ. Bull. Torrey Bot. Club 40: 1-26. 1913. 
“Shreve, Edith B., “ The daily march of transpiration in a desert 
perennial.” Carnegie Inst. Wash. Pub. 194: Washington, 1914. 
