152 ISABURO NAGAT: 
V. The Effect of Extremes of Temperature on the 
Germinative Power. 
It is a well known fact that the seed can withstand extremes of 
temperature, especially in the desiccated condition. In regard to high tem- 
perature, HABERLANDT, as early as 1863, showed that the dried seed can 
withstand 48 hours’ exposure at 100°C. Just (1877) observed the increase 
in the resistance to heat by the degree of desiccation of the seed. VON 
Houvet (1877) showed that fully dried seeds could withstand an hours’ ex- 
posure at 110°—125°C. Dixon (1901) demonstrated that the seed of various 
kinds of plants, such as Avena sativa, Lolium perenne, Lactuca sativa, Helianthus 
argophyllus, Mimulus moschatus, Medicago sativa, Brassica Rapa, Eschscholtza 
californica, Papaver somniferum, &e. can resist at least 100°C. The seed 
of Medicago can be germinated (10%) after one hours’ exposure at 110° 
followed by another one hour’s exposure at 121°. The effect of exposure 
to high temperature could in all cases be observed in the marked retarda- 
tion of germination and in the extremely slow growth afterwards. WHITE 
(1909) was able to show that many of the seeds of barley, wheat, and oats 
could be germinated after '/, hours’ exposure to 99—100°C, but after 6'/, 
hours’ exposure none of the seeds germinated. One hours’ exposure to 122° C 
also destroyed the vitality of the seeds. : 
The effect of low temperature was investigated by DE CaNnDoLLE (1895), 
Brown and Escompr (1898), Tutsrnron-Dyrr (1899), BECQUEREL (1907) and 
Wurre (1909). Brown and EscomBE exposed the seed of Hordeum distichon, 
Avena sativa, Cucurbita Pepo, Cyclanthera eaplodens, Lotus Tetragonolobus, 
Pisum elatius, Trigonella Foenum-graecum, Impatiens balsamina, Helianthus 
annuus, Heracleum villosum, Convolvulus tricolor, Funkia Sieboldiana to liquid 
air (—183° to —192°C) for 50 hours, but no appreciable difference was 
observed with the control seeds. The seeds of Brassica alba, Pisum sativum, 
Cucurbita Pepo, Mimulus moschatus, Triticum sativum, and Hordeum vulgare 
were tested by T'uHisenton-DyER. The subjection to extreme low temperature 
(—250°) “did not show the smallest visible trace of the ordeal.” BECQUEREL 
(1907), showed that even if the seed coat is removed and the liquid air is 
allowed to penetrate into the embryo, no appreciable difference in the germi- 
