SOME EFFECTS OF INDOLEACETIC ACID AND MALEIC HYDRAZIDE ON THE RESPIRATION AND FLOWERING OF WHEAT

Abstract

Wheat seedlings were grown in sand culture in 1 qt. crocks. Maleic hydrazide (10 mg. per crock per day) prevented flowering and increased the oxygen consumption per unit dry weight of the first leaves by 20 to 50%, but did not alter the C₆/C₁ ratio, which was measured by incubating leaf disks with glucose-6-C¹⁴ and glucose-1-C¹⁴. Indoleacetic acid (0.5 mg. per crock per day) increased oxygen uptake by only 10 to 15%, but stimulated flowering and apparently lowered the C₆/C₁ ratio. The C₆/C₁ ratio of leaf disks was approximately halved by 2 hours pretreatment with 5.0 and 8.3 p.p.m. of indoleacetic acid, mainly because of a decrease in the recovery of C₆.The results are discussed briefly in relation to the effect of obligate parasites in increasing the indoleacetic acid content and in lowering the C₆/C₁ ratio of susceptible cereal leaves.