Figures (4)  Tables (1)

    • Figure 1. 

      Pluripotent calli and shoots regenerated from leaf explants of Vaccinium corymbosum 'Diana'. (a) Leaf explants were cultured on regeneration medium for 15 d under dark conditions, and the pluripotent calli were induced from the edge of explants. Arrows indicate the shoot primordia and embryoid structures. (b) Adventitious shoots were regenerated from leaves after transferring to light conditions for 30 d. Scale bar = 1 mm.

    • Figure 2. 

      Detection of chromosome ploidy by flow cytometry and microscopic observation of leaf stomata. Relative fluorescence intensity of plant chromosome nuclei of chromosome-doubled plant (c) and its progenitor (a). The size and density distribution of leaf stomata derived from tetraploid (b), and octoploid (d) was observed under a microscope (40×). Scale bar = 50 μm.

    • Figure 3. 

      Growth characteristics of chromosome-doubled blueberries. (a) Tissue culture seedlings of tetraploid (left) and octaploid (right) blueberries. (b) Comparison of leaf and flower buds between tetraploid (left) and octaploid (right) plants. (c) Blade length of tetraploid and octaploid plants was analyzed using Student's t-test. (d) Blade width. (e) Growth of annual octaploid plants. (f) Plant height. (g) Flowering status of biennial octaploid plants. (h) Number of canes. Scale bar = 1 cm. Asterisks indicate significant difference.

    • Figure 4. 

      Comparison of fruit morphology between octaploid and tetraploid blueberries. Comparing the morphology and cross-sectional structures of (a), (b) octaploid fruits to the (c), (d) original tetraploid fruits, including (a), (c) green young fruits, and (b), (d) blue ripe fruits respectively. The (e) ripe fruit weight and (f) diameter in tetraploid and octaploid were analyzed using Student's t-test. Scale bar = 0.5 cm.

    • Treatment agents concentration
      (mg/L)      		 No. of explants Survival rate
      of explants %      		 No. of shoots per explant No. of polyploid
      CK 0 36 100a 6.92 ± 0.804a 0
      Trifluralin 0.5 36 100a 4.28 ± 0.746b 0
      1.0 36 100a 2.97 ± 0.255c 0
      2.0 36 86.11 ± 4.815b 1.89 ± 0.348d 6
      5.0 36 77.78 ± 4.809c 0.61 ± 0.314e 6
      10.0 36 55.56 ± 4.809d 0.25 ± 0.080e 3
      Colchicine 10 36 100a 5.58 ± 0.217b 0
      20 36 100a 3.94 ± 0.648c 0
      50 36 88.89 ± 4.815b 3.44 ± 1.210c 0
      100 36 75 ± 8.33c 1.11 ± 0.172d 0
      200 36 52.78 ± 4.809d 0.42 ± 0.085d 3
      Different lowercase letters indicate statistical significance (Duncan's new multiple range test, p < 0.05).

      Table 1. 

      The effects of trifluralin and colchicine on shoot regeneration from leaves of blueberry.