Der Einfluss des Klimas auf den Bau, der Pflanzengewebe Anatomisch-physiologische Untersuchungen in den Tropen

Abstract

DR. HOLTERMANN's investigations, mainly carried out in Ceylon, include a long series of experiments on the transpiration of different tropical plants. His tables show great variations in the amount of transpiration for the same plant during the same hours of different days, and these are in many cases not explained by the differing temperature and relative humidity, which are the only other data given. Thus, for instance, in the case of Canna indica, between 9.40 a.m. and 5.40 p.m. on January n (with a relative humidity of 61 and a temperature of 25°.4 at 10 a.m.), the transpiration was 0.37 gr. per hour per sq. dm. of leaf surface, while on January 17, between 9.45 a.m. and 5.30 p.m. (R.H. 63, temp. 26°.2, at 11.15 a.m.), the transpiration; was 0.92 gr. per hour per sq. dm., and on January 18 between 9.15 a.m. and 3.30 p.m. the transpiration was 2.60 gr. per hour per sq. dm. (no humidity or temperature data are given within the period of the experiment, but judging from the late afternoon figures the day did not differ much from the others). This, though an extreme case, is only one out of several similar ones, and the effect of, such figures on the reader is decidedly bewildering, though the striking variations may be explicable by changes of insolation, or the irregular occurrence of drying winds. As they stand, the author's figures only demonstrate that the transpiration of the plants studied exhibited startlingly wide fluctuations which remain quite unexplained.

Der Einfluss des Klimas auf den Bau, der Pflanzengewebe. Anatomisch-physiologische Untersuchungen in den Tropen.

By Dr. Carl Holtermann. Pp. viii + 249; plates. (Leipzig: W. Engelmann, 1907.) Price 12 marks.