高油玉米灌浆期籽粒可溶性糖含量与脂肪积累的关系

以田间种植的春玉米高油(通油1号)和高淀粉(郑单19号)为材料,探讨玉米高油杂交种可溶性糖含量变化与脂肪积累的关系。从授粉后7d开始,每隔7d选取果穗测定籽粒的蔗糖、葡萄糖、果糖和脂肪含量。结果表明,2个杂交种玉米籽粒油份的百分含量在整个灌浆过程中都呈不断上升的趋势,而成熟时略有下降。整个灌浆过程中通油1号的油份百分含量始终高于郑单19号。2个玉米杂交种籽粒蔗糖含量峰值在授粉后14d出现高峰,然后逐渐下降,通油1号的峰值明显高于郑单19号;其籽粒的果糖含量在授粉后14d出现峰值,然后急速下降,通油1号的峰值高于郑单19号;籽粒葡萄糖含量从授粉7d后开始下降,42d后趋于平缓,在授粉后21d前是通油1号葡萄糖含量低于郑单19号。说明籽粒灌浆前期,碳水化合物供应不是脂肪合成的限制因素,而果糖向乙酰CoA的转化速率可能是脂肪合成的限制步骤。

Relationship between Fat Accumulation and Soluble Sugar Contents in Kernels During Grain-filling Stage in Maize

Spring maize hybrids Tongyou 1(high oil) and Zhangdan 19(high starch) were grown in the experimental field in Lishu County of Jilin Province to investigate the relationship between soluble sugar content changes and fat in grain during grain-filling period.After pollinated,the ears were taken from plants every seven days,and then,contents of sucrose,glucose,fructose and fat in kernals were determined.Results show that fat contents,in 2 hybrids kernels,increase gradually during grain-filling stage and decline slightly in the late stage.Fat contents in Tongyou 1 are higher than those in Zhengdan 19 during grain-filling stage.Sucrose contents in grains in 2 hybrids reach the peak at 14d after pollination,and then decrease gradually.The peak in sucrose contents in Tongyou1is higher than that in Zhengdan19.Fructose contents in kernels in 2 hybrids reach the peak at 14d after pollination,and then decrease dramatically.The peak in fructose contents in Tongyou1is higher than that in Zhengdan19.Glucose contents in kernels in 2 hybrids decline from 7d after pollination and remain stable 42d after pollination.Glucose contents in Tongyou1 are lower than those in Zhengdan19 in 21d after pollination.These results suggest that the transformation of fructose to acetyl CoA rather than carbohydrate supply might be a limited step in fat biosynthesis in kernels during grain-filling stage in high-oil maize.