Factors Affecting Leaf Area Development in Husk Leaf of Flint Corn
1997
Satō, Hideo | Sakurai, Naoki | Sendo, Sigeyuki | Saneoke, Hirofumi | Nobuyasu, Hiroyuki | Fujita, Kounosuke
Some corn (Zea mays L.) genotypes produce husk leaves (laminae extending from the husk) that on a per unit area basis, contribute more photosynthate to grain production than culm leaves. Furthermore, a high correlation between husk leaf area and dry weight has been observed, but little is known about the changes in cell components during development of husk leaves. A field experiment was conducted to quantify methanol (MeOH)-soluble fraction (cytosol) and incorporation of ¹³C-labeled photosynthate in cell walls from 9 d before silking (DBS) to silking. The ear leaf of flint corn (F₁ of N-19 by X-15) was subjected to ¹³CO₂ eight DBS. Leaf area, dry weight, and photosynthetic activity of the husk leaves, and sugar content of various cell components were measured continuously during the 9-d period. The husk leaf attained one-half of its maximum apparent photosynthetic rate (P₀) when it had 8% of its maximum leaf area at 4 DBS. At 9 DBS, neutral sugars in the MeOH-soluble fraction accounted for most of nonstarch carbohydrates within the husk leaf (68%), while hemicellulose and cellulose fractions accounted for <10%. At silking, however, sugars in the hemicellulose and cellulose fractions increased by 23 and 56%, respectively. Results of ¹³CO₂ labeling suggest that during rapid husk leaf development, MeOH-soluble fraction decreases, while the hemicellulose fraction fluctuates, and cellulose fraction increases.
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