Effects Of Temperature And Sunshine Ecological Factors And Planting Density On Development Of Kernel In Maize (Zea Mays L.)

The study was conducted at the Dongbeiwang farm of Haidian district in beijing in 2002 and 2003. The experiment consists of main experiment and assistant experiment.The treatments are three sowing dates and two planting densities. The variety of maize in main experiment is "Zhengdan958". The material of maize in assistant experiment is "024". The content of the study is effects of temperature and sunshine ecological factors made by different sowing date and planting density on development of maize kernel.The main results are as follows:1. Different sowing date makes the differences of every phase and temperature & sunshine conditions of every phase. Compared with spring maize,the growth time and kernel development time of summer maize are shortened. In different sunshine and temperature ecological factors, filling time of sowing maize in 18 May is longest and 12 June' is shortest. Accumulated temperature and average temperature of filling phase in the two sowing dates respectively are 1249.9℃ and 914.6℃; 23.1℃ and 20.3℃.2,1000-kernels weight of sowing maize in 18 May is biggest. 1000-kernels weight of sowing maize in 12 June is lightestThe remarkable differences of 1000-kernels weight in different planting density (except 12th,June sowing date). With interaction between sowing date and planting density. 3, In different temperature and sunshine ecological factors and planting density, a result on the difference of maize yield of "Zhengdan 958".With sowing date postponing, the yield descend. With the increment of the density, the yield increase.4,In different temperature and sunshine ecological factors,in different stage LAI is changed. Compared with spring maize,LAI of summer maize are low. And LAI of low density is low LAI in whole growing period.The influence of dry matter accumulation with the community and single plant is no obvious difference before silk and positive relativity between dry matter accumulation and sowing date after silk, early sowing date makes big dry matter accumulation after silk. With the increment of the density, dry matter accumulation of the single plant reduce, the community increase.In the aspects of dry matter distribution ,early sowing date makes more dry matter distribution to ear after silk. With the increment of the density, the proportion of stem,leaf, stalk+ bract in single plant increases.But the proportion of the ear in o single plant decreases.5,Remarkable differences of endosperm cell number between middle kernels and top kernels. Endosperm cell number of middle kernels is so much than top kernels.No differences of kernels endosperm cell number in temperature and sunshine ecological factors and different density.6, Influence of middle kernels of ear filling velocity by temperature and sunshine ecological factors and density is primarily in back filling phase. As for top kernels of ear filling velocity, with the stage effected by ecological factors and different density.Relationship between filling time & filling velocity and accumulated temperature in filling phase.In linearity filling phase, positive relativity between fillingvelocity and air temperature.7, Temperature and sunshine ecological factors and density affect supply and movement of assimilation products. Assimilation products of stem lack in back filling phase in summer sowing(12 June) and 5000 plants/667m2.No much differences of cane sugar in ear leaf in different sowing date. Differences of cane sugar in ear leaf in different density .No much effect of cane sugar in middle kernels in different ecological factors.The effect by density is in back filling phase.8, Under the conditions of this study, Kernels weight of sowing maize in 18 May is biggest. Yield of 5000 plants/667m2 is highestBut sowing maize in 18 May in 5000 plants/667m2 is not best and because number of ear decreases.