| Abstrakt: |
Three summer maize (Zea mays L.) hybrids with different plant heights, DengHai661 (low-plant height hybrid, DH661), ChaoShi3 (medium-plant height hybrid, CS3), and XianYu335 (high-plant height hybrid, XY335), were used to explore photosynthetic characteristics of maize and its responses to plant density. Results showed that grain yield increased with the increase of plant density. At 90,000 plants ha-1, grain yield of DH661 was the highest. With increasing plant density, yield increment of DH661 was biggest, while leaf area index (LAI), chlorophyll content, and net photosynthetic rate (Pn) of DH661 changed less with increasing plant density. Grain yield of DH661 at 90,000 plants ha-1 increased by 34 and 21%, respectively, compared to that at 45,000 and 67,500 plants ha-1, CS3 increased by 18 and 9%, respectively, and XY335 increased by 7% and not significant (ns), respectively. Before the flowering stage, the photosynthesis of leaves that just entered function stage played a dominant role. Aft er the flowering stage, the photosynthesis of top and middle leaves mainly played the leading role. The difference of Pn among three parts (top, middle, and bottom) of DH661 was less than that of XY335, and the same as the effect of plant density. There were no significant differences between DH661 and XY335 in the Pn of top leaves, while Pn of middle and bottom leaves of DH661 were significantly higher than that of CS3 and XY335. Visibly, low-plant height hybrid might be more beneficial for high yield cultivation under dense planting conditions. [ABSTRACT FROM AUTHOR] |
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