The Study On Physiological Characteristics Of Source-sink And Potential Of Grain Yield In High Oil Corn

High oil corn(HOC) is a value-added corn cultivar's type,which containsmore oil and higher quality protein than that of normal corn (NC). HOC hasnot been widely planted by growers because its grain yield is lower than NC.The experiment was conducted to document the limited factor of High OilCorn (HOC) grain yield which is the assimilate supply (source strength) or theinherent potential of the kernel (sink capacity). The physiologicalcharacteristics of source and sink were studied on HOC by defoliation and halfpollination of the topmost ear at flowering in field under freely growingconditions. Then the effects of different nitrogen and density treatments on thephysiological characteristics of source and sink, the grain yield and grainquality of HOC was studied compared with NC. The feasible methods forhigher grain yield and better grain quality were put up. The major results asfollowing:1 The components of grain yield of HOC Compared with NC, the grain yield of HOC was 90.6 percentage of thatof NC. As to the components of yield, the different of 1000-kernel weightdistinct between both HOC and NC under freely growing conditions,1000-kernel weight of HOC was 5.08 percent lower than that of NC underother density. But no significant difference was found between kernel numberper ear.2 The limited factor of HOC grain yield 4山东农业大学硕士研究生毕业论文 The effect of altered source-sink ratio on dry weight per kernel wassignificant. Half pollination of topmost ear, the dry weight per kernel of HOCincreased distinctly, about 9.69 percent higher than that of control plant. Thatof NC increased 1.65 percent. When half leaves were clipped, the dry weightper kernel of HOC decreased 7.74%, which of NC only decreased 5.73 percent.Compared with NC, the effects of altered source-sink ratio on dry weight perkernel of HOC is more sensitive, which indicated that a predominant sourcelimitation for grain yield in HOC.3 The Physiological characteristics of leaf source During the period from pollination to physiological maturity, a decreasein leaf area, net photosynthesis rate, photosynthesis pigment, content andnitrogen concentration in ear leaf of HOC was found with development ofstage in maize. The grain yield of HOC is lower than that of NC for its smallerleaf, lower nitrogen concentration in leaf and net photosynthesis rate , thoughthose of HOC decreased slowly after pollination .In conclusion,the grain yieldof HOC was limited by both of the quantity and activity in leaf source. A decrease of source-sink ratio prompted a decrease in SOD activity,POD activity and soluble protein content in ear leaf, the reason of which maybe defoliation caused leaf hurt. Whereas there was a significant increase in netphotosynthesis rate, photosynthetic pigment content, PEP case activity in earleaf and soluble sugar concentration in leaf as the source-sink ratio decreased.In addition, the amplitude of HOC was bigger than that of NC. Both the leaf area index and duration on leaf area of HOC increased witha increase of nitrogen and density treatments. But the amplitude of HOC issmaller than that of NC. An increase was found in net photosynthesis rate,photosynthetic pigment content, Nitrogen concentration in leaf and PEP caseactivity all increased with increase of nitrogen level and decrease of densitybut the degradation lower than NC. That's to say the source activity of HOCwas better when the nitrogen fertilizer level was high,but the effect ofdifferent density level on it was more sensitive for NC than HOC. 5吴正锋:高油玉米源-库生理特性及产量潜力研究4 The Physiological characteristics of sink HOC has similar potential of sink capacity per ear with NC, but lowergrain filling rate and grain filling index. The grain filling rate of HOCdecreased with development of stage in maize,but increased with a increase ofthe ratio of sourc...