Osocitric Dehydrogenase and Isocitric Lyase in Heterotic and Nonheterotic Maize (Zea mays L.)1
- Eric E. Roos and
- 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 220.127.116.11) and isocitric lyase (Ls-isocitrate glyoxylate-lyase EC 18.104.22.168.) 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.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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