Effect of Maleic Hydrazide on the Respiration of Mature Onion Bulbs

Morphological and Physiological Effects of Maleic Hydrazide on Tobacco

“…Increased and/or decreased respiratory activity following maleic hydrazide treatment has been reported for many different plant tissues (Dawson 1955, Isenberg 1954, Naylor and Davis 1950. Jyung et al (1965) reported that maleic hydrazide greatly increased respiratory activity of tobacco leaf cells, whereas Baker (1961) showed a 15 % inhibition in respiratory activity following vacuum infiltration of tobacco leaf discs with a 10"^ M solution of maleic hydrazide.…”

Studies of Maleic Hydrazide Interactions with Thiol Compounds.

“…In outline, germination was made over washed cheese cloth suspended over a dilute macronutrient supply contained in shallow Pyrex or polyethylene vessels. Seedlings were transferred at an early first-true-leaf stage of development (about 10 days) to solution culture media contained in 4 Micronutrient deficiency studies were made with a uniform macronutrient supply (4). Micronutrients were added as salts (without ethylenediamine tetraacetate) as described elsewhere (4), omitting that one concerned with the element under investigation.…”

“…Naylor and Davis (2) and Isenberg et al (3,4) suggest that maleic hydrazide is a respiratory inhibitor, at least at higher concentrations. Greulach and coworkers (5,6) report that maleic hydrazide restricts growth primarily by inhibiting mitosis.…”

“…Second, Morgan and Friedman (14) noted that maleic acid, structurally related to maleic hydrazide, does react with a number of thiols. Hopkins and collaborators (15,16) found that maleic acid reacted with the thiol groups of proteins and thereby inhibited succinic de- 4 Maleic hydrazide is named systematically as 1,2-dihydropyridazine-3,6-dione. hydrogenase activity.…”

“…A boiled homogenate was prepared by heating an aliquot of the homogenate in a boiling water bath for 10 minutes. The reaction mixtures, controls and reaction mixtures plus tissue homogenates were incubated up to 4 days at 370 C. To determine free thiol groups, 1.0 ml aliquots of the reaction mixture were taken at 0 time, and at definite time intervals after incubation. The amount of thiol in the aliquots was estimated by adding an excess of standard iodine solution and the excess iodine back titrated with standard thiosulfate using starch as the internal indicator.…”