[Study on preparation technology of limonene dropping pills].

Objective: To study the technical preparation of limonene dropping pills.

Methods: Orthogonal test was applied to optimize the preparation of limonene dropping pills.

Results: The optimized project was as follow: the matrix contained PEG4000: PEG6000 (1:1.

[Transgenic maize plants with low copy number of foreign genes were produced with maize Ubi-1 promoter].

Direct DNA delivery procedures (include biolistics method) often resulted in multiple copies of the transgenes in transformants and certain copies of them were rearranged. Integration of multiple copies of the introduced genes was the main reason of gene silencing which meant inhibition or loss of foreign gene expression in filial generations of transformants. In the present work, we compared the influences of maize Ubi-1 promoter and other promoters on copy number of transgenes in maize transgenic plants.