824 EXPERIMENT STATION RECORD. [Vol.36 



the several values being tabulated. An approximate measure of the increase 

 is furnished by sets of temperature coefficients shown for each rise of 10° 

 between 5 and 40° by the onion leaf and dandelion scape. 



Further studies on foliar transpiring power in plants, A. L. Bakke and 

 B. B. Livingston (Physiol. Researches 2 (1916), No. 2, pp. 51-71, figs. S). — 

 These studies carry forward the work previously reported (E. S. R., 34, p. 334), 

 employing herein Xanthium canadense and Helianthus annuus. The tests 

 were made on leaves of various ages and at different hours. 



The results are said to agree throughout in showing a daily cycle of change 

 in the average foliar transpiring power of the plant, as a whole, from low night 

 values to high day values and vice versa, as already ascertained in other plants. 

 The maximum value of the average index of foliar transpiring power occurred 

 about the tenth hour of the day in July and August, the two plants behaving 

 much alike in this respect. The minima occurred about the eighteenth or else 

 about the twenty-second or twenty-third hour of the day, and are also much 

 alike for the two plants. Apparently the diurnal is three to five times the 

 nocturnal transpiring rate. The increase occurring within one hour from just 

 before sunrise to just after amounts to 240 per cent in Xanthium and 90 per 

 cent in Helianthus. Older branches attain to lower maximum values and have 

 more restricted daily ranges. 



A single index to represent both moisture and temperature conditions as 

 related to plants, B. E. Livingston (Physiol. Researches, 1 (1916), No. 9, pp. 

 421-440, fig. 1). — This is a more detailed account than that previously noted 

 (B. S. R., 35, p. 732). 



The respiration of partly dried plant organs, A. M. Smith (Abs. in Rpt. 

 Brit. Assoc. Adv. Set., 85 (1915), p. 725). — Tests were made with such plant 

 organs as leaves of snowdrop, stem tips of Tropseolum, and young stems of 

 asparagus, by depriving them, by means of a vacuum desiccator, of different 

 proportions of the water they contained and then measuring their output of 

 carbon dioxid. 



The results show that in some cases respiration was increased after the plants 

 bad been deprived of one-third to one-half of their water content. The experi- 

 ments thus far completed, while inconclusive, do not indicate reversibility in 

 this process. 



Investigation of the course of respiration with various degrees of deprivation 

 of water content (fresh plants being used for each test) showed three phases 

 of the course of the resulting respiration. Up to about 30 per cent of water 

 loss, the increase of respiration was proportional to the loss of water. Respira- 

 tion then remained about the same during a decrease of water content ranging 

 from 25 or 30 per cent up to 50 or 60 per cent. Above this limit to that of 

 complete dryness, respiration decreased proportionally to the amount of water 

 lost. 



The meaning of the increased protoplasmic respiration in partly dried mate- 

 rial is deemed not clear. It has been suggested that the increased respiration 

 shown in these experiments may be due to the increased activity of one or more 

 enzyms. 



Physiological studies on the maturation of seeds, S. L. Ivanov (Soohshch. 

 Biuro Chastn. Rast. [Petrograd], S (1916), No. 2, pp. 49). — The author, re- 

 porting upon a series of studies with pure lines of peas, flax, wheat, and oats, 

 claims that the capacity of being changed into insoluble forms is the chief 

 factor In the transmission of mineral and organic substances from stem to 

 seed. In case of annuals the maturing of seeds exhausts the plant and thus 

 leads eventually to its death. The process of maturation of the seeds has a 



