The path of carbon in photosynthesis: improved crop yields with methanol.

Foliar sprays of aqueous 10-50% methanol increased growth and development of C3 crop plants in arid environments. The effects of low levels (< 1 ml per plant) of methanol were observed for weeks after the brief time necessary for its rapid metabolism. Within several hours, foliar treatment with methanol resulted in increased turgidity. Plants treated with nutrient-supplemented methanol showed up to 100% increases in yields when maintained under direct sunlight in desert agriculture. In the shade and when winter crops were treated with methanol, plants showed no improvement of growth. When repeatedly treated with nutrient-supplemented methanol, shaded plants showed symptoms of toxicity. Repeated methanol treatments with glycine caused increased turgidity and stimulated plant growth without injury under indirect sunlight, but indoors with artificial illumination, foliar damage developed after 48 hr. Addition of glycerophosphate to glycine/methanol solutions allowed treatment of artificially illuminated plants indoors without injury. Plants with C4 metabolism showed no increase in productivity by methanol treatment. Plants given many applications of aqueous methanol showed symptoms of nutrient deficiency. Supplementation with a source of nitrogen sustained growth, eliminating symptoms of deficiency. Adjustment of carbon/nitrogen ratios was undertaken in the field by decreasing the source of nitrogen in the final application, resulting in early maturation; concomitantly, irrigation requirements were reduced.