DEPARTMENT OF BOTANICAL RESEARCH.* 



D. T. MacDougal, Director. 



The development of the researches carried out under the auspices 

 of the Department has resulted in a concentration of the attention of 

 the members of the staff and collaborators upon problems in photo- 

 chemistry, especially phyto-chemistry, and in the environic reactions 

 of organisms with especial reference to light, temperature, and mois- 

 ture, and also to the correlation of such physical and physiological 

 results with geographic occurrence, distributional movements, and 

 genetics of organisms. 



Such progress has been made in the first-named subject that it is 

 now possible to formulate definite methods looking toward the deter- 

 mination of the actual manner in which the energy of hght acts upon 

 living matter, not only in the chlorophyll processes, but in its other 

 probable ionization effects. A small laboratory especially fitted for 

 such work has been planned, which will furnish adequate facilities 

 for the extension of the preliminary results. 



Some additional results on the relation of plants to climatic com- 

 plexes secured from the experimental cultures in the montane plan- 

 tation and at the coastal laboratory have made available certain 

 qualitative data upon the basis of which a factorial laboratory may 

 be planned with a high degree of promise as to its efficiency and 

 importance of results, and the next opportunity for increasing the 

 equipment of the Department will be devoted to the organization 

 of facilities of this character. Adequate power for furnishing heat, 

 refrigeration, light, pressure, and moisture-control under conditions 

 as exactly regulated as those of a bacteriological thermostat in cham- 

 bers large enough for plants of full size during their entire development 

 would be the main feature of a laboratory of this kind. The construc- 

 tion would include such specialties as the substitution of quartz for 

 glass and devices for the calibration of intake and outgo analogous to 

 those necessar}^ in the operation of a respiration calorimeter. These 

 facilities would enable the researcher to analyze or totalize the effect 

 of any one of the single factors which make up ''environment" and 

 test the behavior of organisms with reference to their previous indi- 

 vidual experience or genetic history. Definite advance in some of 

 the main problems of physiology must await the organization of such 

 equipment, which at present does not exist. 



*Situated at Tucson, Arizona. Grant No. 859. $38,005 for investigations and main- 

 tenance during 1913. (For previous reports see Year Books Nos. 2-11.) 



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