This work is concerned with some physiological and biochemicalstudies of the lipids of higher plants, a subject inwhich only an extremely limited number of studies havepreviously been made.
From a study of plants grown under controlled conditions,it was found that both character and amount of fat and waxproduced by a plant may be affected by a factor of two or threeby day and night temperatures and soil moisture. The effectof increased day or night temperature on the yield of fat wasdifferent for different species. Plants generally responded toincreased temperature by producing less wax. The fats and waxesfrom plants at high temperatures were of a higher melting pointthan those from plants at low temperatures. Water stress plantsalso produced large amounts of fat, or in Larrea, resin. Althoughthe wax content was only slightly affected by low soil moisture,in Nicotiana glauca an abundant formation of cuticle occurredunder this condition. These and other effects of climate onlipids were discussed.
Whereas changes in climate effect up to three-fold changesin lipid yield, a series of recessive genes in corn was found tocontrol ten-fold changes in wax yield. The genetic factors alsoaffect the character and yield of the fats.
A system was obtained for studying the synthesis of fats ina higher plant. Preliminary results show that short chaincompounds (ethyl alcohol, acetate, acetone, acetoacetate) may berapidly utilized in the synthesis of fat. These substrates arereadily used only when an energy source such as sugar and the vitamin biotin are supplied. The effects of other substrates andvitamins on fat synthesis were also studied and found to be smallor altogether absent.
