TECHNOLOGY FOCUS - BIOLOGY - Preparation: No preparation method is given. Preferred Components: The chimeric protein has transcriptional repression factor activity. The functional peptide has an amino acid sequence of formulae X1-Leu-Asp-Leu-X2-Leu-X3, Y1-Phe-Asp-Leu-Asn-Y2-Y3, Z1-Asp-Leu-Z2-Leu-Arg-Leu-Z3, Asp-Leu-Z4-Leu-Arg-Leu, alpha1-Leu-beta1-Leu-gamma 1-Leu, alpha1 -Leu-beta1-Leu-gamma2-Leu, alpha1-Leu-beta2-Leu-Arg-Leu, and alpha2-Leu-beta1-Leu-Arg-Leu. The plant body is an angiosperm, a dicotyledon or Arabidopsis thaliana. Preferred Method: The substance productivity per individual plant is significantly improved or decreased. The substance productivity per individual plant is productivity of fats and oils contained in seeds. In (I), the activity of accelerating transcription of the transcriptional factor is suppressed.X1, Y1, Z3 = 0-10 amino acid residues;X2 = Asn or Glu;X3, Y3 = at least 6 amino acid residues;Y2 = Phe or Ile;Z1 = Leu, Asp-Leu or Leu-Asp-Leu;Z2 = Glu, Gin or Asp;Z4 = Glu, Gln or Asp;alpha = Asp, Asn, Glu, Gin, Thr or Ser;alpha2 = Asn, Glu, Gln, Thr or Ser;beta1 = Asp, Gln, Asn, Arg, Glu, Thr, Ser or His;beta2 = Asn, Arg, Thr, Ser or His;gamma1 = Arg, Gln, Asn, Thr, Ser, His, Lys or Asp; andgamma2 = Gin, Asn, Thr, Ser, His, Lys or Asp. EXAMPLE - Arabidopsis thaliana was used as a plant for introduction of the modified transcriptional factor. A gene transfer was carried out by vacuum infiltration. The plants were only infected by immersing them in an Agrobacterium solution without performing decompression treatment. A modified transcriptional factor expression vector pBCKHp35SSXG was introduced into soil bacterium Agrobacterium tumefaciens strain GV3101, thus the introduced bacteria were cultured in 1 l of yeast extract peptone (YEP) medium containing an antibiotic (kanamycin (50 mu g/ml), gentamicin 25 mu g/ml, and rifampicin (50 mu g/ml)). Subsequently, bacteria were collected from the culture solution and then suspended in 1 l of medium for infection. Arabidopsis thaliana plants grown for 14 days were immersed in the solution for 1 minute for infection. After infection, cultivation was continued to fructification. A harvested seeds were sterilized in 50% bleach with 0.02% Triton X-100 (RTM: Nonionic surfactant) solution for 7 minutes, rinsed 3 times with sterile water, and then germinated on sterilized hygromycin selective medium (containing 4.3 g/l Murashige and Skoog (MS) salts, 0.5% sucrose, 0.5 g/l (2-N-morpholino)ethanesulfonic acid (MES), 0.8% agar, 30 mg/l hygromycin, and 250 mg/l vancomycin). Ten lines of transformed plant bodies that had grown on the hygromycin selective medium were selected per modified transcription gene. A plant was then transplanted into pots with a diameter of 50 mm containing vermiculite mixed with soil. They were cultivated at 22 degrees C under 16 hours-light/8 hours-dark photoperiods and light intensity of 60-80 micro mol m-2S-1.