CHAPTER III 



INFLUENCE OF EXTERNAL CONDITIONS ON GROW 1 1 1 

 AND CONFIGURATION 1 



§1. Dependence of Growth and Configuration upon Temperature. 

 Medium temperatures 2 are most favorable for growth, which ceases with very 

 high and with very low temperatures. The following table shows the incre- 

 ments of elongation of three plants for a forty-eight hour period, at various 

 temperatures. 



Temperature 



Lupinus Albus 



(Lupine) 



Pisum Sativum 

 (Pea) 



Triticum Vi 

 Wheal 



The minimum, optimum and maximum temperatures for the growth of 

 several different plants are shown in the next table. This table shows clearly 



Minimum 



Optimum 



Maximum 



Hordt um vulgare (barley) 



Sinapis alba (white mustard) 



Lepidium sativum (garden cress) 



Phaseolus »lu'tijlorus (scarlet-runner bean 



Zea mays (maize) 



Cucurbita pepo (gourd, squash) 



deg.C. 



5 ° 

 0.0 

 1.8 

 9-5 

 95 

 13-7 



deg. ('. 

 28.7 

 21.0 

 21 .0 

 33 7 

 33 7 

 33-7 



37 7 

 2S.0 



40 2 

 40 2 



1 [On plant movements m gener 

 Berlin, 1012.] 



"Koppen, W., Wärme und Pflanzenwachsthu 



Pringsheim, Ernst G., Die Reizbewegungen der Pflanzen. 



Bull. Soc. Imp. Nat. Moscou 4з 7/ : .ji-no. 187 



Sachs, J., Physiologische Untersuchungen aber die Abhängigkeit der Keimung von 



Jahrb. wiss. Bot. 2: 338-377. i860. (Lehenbauer, P. A., Growth of gs in relation to 



temperature. Physiol, res. 1:247-288. 1014. Also see: Fawcett, H. S., Th< relations 



of growth in certain parasitic fungi. Univ. Calif. Pub. Agric. Sei. 4: 183-232, 1921.I 



2 53 



