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This article in CS

  1. Vol. 8 No. 6, p. 683-686
    Received: Mar 19, 1968

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Osocitric Dehydrogenase and Isocitric Lyase in Heterotic and Nonheterotic Maize (Zea mays L.)1

  1. Eric E. Roos and
  2. Igor V. Sarkissian2



Heterotic and nonheterotic maize (Zea Mays L.) hybrids and their inbred parents were studied during eariy postgermination to learn a physiological aspect of the phenomenon of heterosis. The enzymes isocltric dehydrogenase (Ls-isocitrate:NADP oxidoreductase ldecarboxylating] EC and isocitric lyase (Ls-isocitrate glyoxylate-lyase EC from scutellar tissue were assayed spectrophotometrically. When each hybrid was compared with its parents, none showed superior isocitric dehydrogenase activity during the period 2 to 6days following water imbibition. With respect to isocitric lyase activity, a definite heterotic response was observed in those hybrids classified as heterofic; nonheterotic hybrids failed to show heterosis for this enzyme. Lyase activity, first detectable 24 to 48 hours after imbibition, increased rapidly until day 5 and then declined. Differences in lyase activity appeared to be quantitative.

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