Abstract
Two low-light sensitive varieties of sweet corn (Zea mays L.), cultivars Xiantian 5, and Huazhen, were subjected to different shading-intensity treatments during the grain-filling stage in a field experiment in order to clarify physiological mechanisms of lowlight effects on the yield, quality, and sucrose-metabolizing enzyme activity of sweet corn. The results showed that under weak light stress (50% light transmittance), the ear length and diameter, fresh ear yield, grains per row and grain weight, weight per ear and sugar content of the grains decreased sharply, while the bald length and water content of the fresh grains increased significantly. The 50% shading decreased the fresh ear yield, max weight per 100 fresh grains, and soluble sugar content of Xiantian 5 by 40.5, 31.3, and 19.5%, respectively, whereas those of Huazhen were decreased by 17.5, 19.8 and 10.1%, respectively. Shading furthermore suppressed the activities of sucrose phosphate synthase (SPS) and sucrose synthetase (SS), and delayed the emergence of peak SPS activity. Key words: Sweet corn, shading condition, yield, quality, sucrose-metabolizing enzyme.
Highlights
Corn (Zea mays L.) is a typical C4 crop that can hardly reach its light saturation point under sunshine but its yield and quality can be improved with ample light (Wenzel et al, 1989; Mclachlan et al, 1994)
The present study provided a theoretical basis for adapting the sweet corn production to the current climate changes in the region of study and breeding new shade-tolerant varieties
At the early filling stage, weak light stress appreciably reduces the grains per ear and the thousand-kernel weight, and at the middle and late stage, it mainly affects the degree of grain filling (Frans et al, 2021)
Summary
Corn (Zea mays L.) is a typical C4 crop that can hardly reach its light saturation point under sunshine but its yield and quality can be improved with ample light (Wenzel et al, 1989; Mclachlan et al, 1994). The mean sunshine duration decreased significantly at the rate of -40.7 h every 10 years over mainland China, the decline rate in sunshine duration was the largest in summer (-16.8 h every 10 years), and the decline trend in sunshine duration was significantly higher in the eastern region than in the western region, especially in North.
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