Use of double-pane, clear plastic panels with prismatic lower surfaces to direct sunlight downward from the roof, and patterned for diffusion of light from side panels, allowed 93% more sunlight for plant growth than the glass block design used previously in phytotron tests at Davis.

These continuing studies on design have benefited from excellent cooperation and help of the staffs of the Agricultural Engineering and Plant Service Departments, the Rohm and Haas Co., and the A. E. Lilly Co. and from financial assistance from the National Science Foundation, Facilities and Special Programs. The sugar beet crop was grown by Professor R. S. Loomis and Mr. Gary Ritenour of the Agronomy Department. University of California, Davis. The research program on plants is guided by the Planning Committee for Controlled Environmental Facilities for Plants.