Figures (2)  Tables (4)

    • Figure 1. 

      GUS staining results of (a) 'M9', and (b) Malus xiaojinensis after Agrobacterium rhizogenes transformation. The seedlings were grown for 2 months. Scale bar = 1 cm.

    • Figure 2. 

      Hormone contents of Agrobacterium rhizogenes-transformed 'M26' plants, 'M26' untransformed plants were employed as controls. The data are the means ± SD calculated from three biological replicates. Different letters denote significant difference within each tissue type determined by one-way ANOVA (Tukey's test; p < 0.05).

    • Rootstocks Strains Total number of
      infected plants      		 Rooting rate (%)
      'M9' Untransformed 60 3.33 ± 1.67
      K599 134 86.08 ± 5.61**
      MSU440 124 56.68 ± 7.91**
      'M26' Untransformed 60 11.67 ± 1.67
      K599 142 89.96 ± 4.77**
      MSU440 146 76.07 ± 2.79**
      Malus xiaojinensis Untransformed 60 13.33 ± 1.67
      K599 158 79.15 ± 5.58**
      MSU440 213 90.97 ± 1.97**
      The data are means ± SEM calculated based on three biological replicates. The total number of infected plants represents the combined number of plants from three replicates. Asterisks denote significant difference determined by using a two-tailed Student's t test (*p < 0.05, **p < 0.01). The rooting rate (%) = the number of rooted plants/the total number of infected plants × 100%.

      Table 1. 

      Rooting rate of Agrobacterium rhizogenes-transformed rootstocks. The rooting rate was calculated 80 d after transferring to rooting medium.

    • Rootstocks Bacterial concentration (OD600) Total number of infected plants Number of rooted plants Rooting rate (%)
      'M9' 0.4 150 115 76.67
      0.5 162 141 87.04
      0.6 104 68 65.38
      'M26' 0.4 137 105 76.64
      0.5 165 139 84.24
      0.6 124 99 79.84
      Malus xiaojinensis 0.4 138 114 82.61
      0.5 110 101 91.82
      0.6 123 103 83.74
      K599 was used to transform 'M9' and 'M26', whereas MSU440 was employed for the transformation of Malus xiaojinensis. The rooting rate was calculated 80 d after transferring to rooting medium. The rooting rate (%) = the number of rooted plants/the total number of infected plants × 100%.

      Table 2. 

      Rooting rate of transformation with three levels of bacterial culture.

    • Rootstocks Strains Number of
      adventitious roots      		 Adventitious root
      length (cm)      		 Number of
      lateral roots      		 Lateral root
      length (cm)
      'M9' Untransformed 2.2 ± 0.26 3.39 ± 0.4 1.73 ± 0.93 0.13 ± 0.05
      MSU440 3.67 ± 0.61* 3.67 ± 0.73 7.67 ± 2.37* 0.92 ± 0.22**
      K599 4.53 ± 0.71** 2.43 ± 0.29 13.53 ± 2.65** 1.25 ± 0.23**
      'M26' Untransformed 5.94 ± 0.73 5.52 ± 0.65 8.88 ± 2.75 0.47 ± 0.12
      MSU440 7.06 ± 1.03 3.88 ± 0.45* 10.75 ± 3.73 1.08 ± 0.27*
      K599 5.38 ± 0.82 3.74 ± 0.36* 16.38 ± 4.49 1.61 ± 0.27**
      Malus xiaojinensis Untransformed 3.22 ± 0.27 3.81 ± 0.34 7.07 ± 0.86 0.75 ± 0.14
      MSU440 5.89 ± 0.67** 2.85 ± 0.23* 13.07 ± 3.57 1.02 ± 0.21
      K599 2.56 ± 0.35 2.08 ± 0.28** 15.7 ± 4.74 0.5 ± 0.12
      The growth of GUS-positive roots was evaluated 80 d after transferring to root medium. The data are means ± SEM, asterisks denote significant difference determined by using a two-tailed Student's t test (*p < 0.05, **p < 0.01).

      Table 3. 

      Effects of Agrobacterium rhizogenes transformation on root growth.

    • Rootstocks Genotype Rooting rate
      (%)      		 Number of
      adventitious roots      		 Adventitious root
      length (cm)      		 Number of
      lateral roots      		 Lateral root
      length (cm)
      M9 Control 72.01 ± 6.21 4.7 ± 0.58 3.17 ± 0.32 11.41 ± 1.93 1.03 ± 0.12
      AtCKX2 76.11 ± 5.98 6.39 ± 0.66 4.55 ± 0.47* 19.73 ± 3.48* 1.31 ± 0.11
      M26 Control 82.93 ± 2.88 5.74 ± 0.62 4.33 ± 0.34 15.87 ± 2.97 1.71 ± 0.2
      AtCKX2 88.68 ± 3.41 8.3 ± 0.83* 6.65 ± 0.63** 26.52 ± 4.08* 3.29 ± 1.65
      Malus xiaojinensis Control 86.06 ± 2.90 5.46 ± 0.4 2.97 ± 0.17 12.32 ± 1.96 1.01 ± 0.1
      AtCKX2 86.89 ± 2.38 6.54 ± 0.44 3.68 ± 0.2** 19.36 ± 2.96* 1.15 ± 0.1
      The data are the means ± SEM, asterisks denote significant difference determined by using a two-tailed Student's t test (*p < 0.05, **p < 0.01). The rooting rate (%) = the number of rooted plants/the total number of infected plants × 100%.

      Table 4. 

      Effects of overexpressing AtCKX2 gene on root growth. Analyzing the growth of GUS-positive roots.