科研之友
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摘要
Delayed planting causes substantial reduction in crop yield; however, information on physiological regulation of yield reduction is scarce. A field experiment was conducted using four planting dates as treatments, namely, early (September 15); optimal (September 25); late (October 25); and very late (November 15) in 2011 and 2012 to unravel the impact of delayed planting date on canola yield and physiological indexes, including tissue dry matter and carbohydrate profile partitioning. Optimal planting date was considered as a control. Results showed that canola seed yields on late and very late planting dates were severely decreased by 30% and 70%, respectively, compared with those on the optimal planting date because of a decrease in the number of branches and siliques per plant and seed weight. Delayed sowing reduced the inflorescence productivity due to less biomass from initial flowering. Inflorescence sugar profile including fructose, glucose, and sucrose showed more content on the late planting than that on the early and optimal planting date at 28 days after anthesis (DAA) (peak point) indicating they were possibly assigned to gain more biomass. However, starch content in the inflorescence on the early and optimal planting date was much higher than that in the late plantation at 28 DAA, indicating that the photoassimilates were mainly used as seed reserves such as lipids.
