The Effect of Maleic Hydrazide on Certain Dehydrogenases in Tissues of Onion Plants

Some Metabolic Changes in Tobacco Stem Tips Accompanying Maleic Hydrazide Treatment and the Appearance of Frenching Symptoms1, 2

“….The greater calcium and lower phosphorus content of plants treated wit;h maleic hydrazide possibly may be accounted for by a greater relative amount of cell wall material than is in normal plants. Perhaps the excess of manganese is correlated with the inhibition of respiration (Naylor and Davis, 1951) and respiratory enzymes (Isenberg et al, 1951). The only correlation with the treated samples that appears in the analysis of frenched plants is the small excess of calcium.…”

“…In the former reducing sugars accumulated, whereas in the latter reducing sugars were at a starvation level while non-reducing sugars accumulated. Since it is known that maleic hydrazide inhibits certain enzymes of the organic acid cycle (Isenberg et al, 1951) and also respiration (Naylor and Davis, 1951), it is possible that the use of carbohydrates as a respiratory substrate may be inhihited in both the treated and frenched plants.…”

Effect of Maleic Hydrazide on Normal and Atypical Growth of Rumex Acetosa

“…The mechanism of its action is unknown, but experiments aimed at solving this problem are in progress. Publications to date which might have a bearing on this subi ect suggest: it acts in opposition to the natural hormones in plants (Leopold and Klein, 1951) ; it affects the dehydrogenase enzymes (Isenberg et al, 1951); it is antimitotic in its action rather than affecting cell elongation (Deysson and Rollen, 1951;Greulach, 1951;Greulach and Atchison, 1950; see also Darlington and McLeish, 1951); it affects carbohydrate metabolism, causing an accumulation of carbohydrates and the appearance of anthocyanins (Currier et al, 1951;Greulach, 1950;Moore, 1950;Naylor, 1951: Navlor andDavis, 1950;Zukel, 1950a) : and it inhibits respiration of root tips (Naylor and Davis. 1951).…”

Sugar Beet Response to Maleic Hydrazide Treatment1,3

“…Evidence presented by Isenberg et a!. ( 6) and Naylor and Davis (9) indicates that dehydrogenase respiratory enzymes are inactivated by maleic hydrazide treatment. Carbohydrates and especially sugars were observed to accumulate in treated cotton plants ( 8) .…”