Figures (4)  Tables (5)

    • Figure 1. 

      Effects of plant growth regulator treatments on (a) bud number, (b) increase in rhizome diameter, and (c) rhizome weight in three Iris species (I. ensata, I. ensata var. variegata, and I. sanguinea). The treatments included: A0 (control group), A1 (low concentration of 6-BA, 1,000 mg/L), A2 (high concentration of 6-BA, 2,000 mg/L), A3 (low concentration of PC, 500 mg/L), and A4 (high concentration of PC, 1,000 mg/L). Each bar represents the mean (n = 12) ± standard error. The significant differences within each species compared to the A0 (control group) were analyzed using Tukey's HSD test following one-way ANOVA (* p < 0.05, ** p < 0.01, *** p < 0.001).

    • Figure 2. 

      Effects of plant growth regulator treatments on plant height of three Iris species (I. ensata, I. ensata var. variegata, and I. sanguinea) during the growing season. The treatments included: A0 (control group), A1 (low concentration of 6-BA, 1,000 mg/L), A2 (high concentration of 6-BA, 2,000 mg/L), A3 (low concentration of PC, 500 mg/L), and A4 (high concentration of PC, 1,000 mg/L). (a) May; (b) June; (c) July; (d) August; (e) September; and (f) October. Each bar represents the mean (n = 12) ± standard error. The significant differences within each species compared to the A0 (control group) were analyzed using Tukey's HSD test following one-way ANOVA (* p < 0.05, ** p < 0.01, *** p < 0.001).

    • Figure 3. 

      Effects of plant growth regulator treatments on (a) number of flowers per plant, and (b) flower stalk height in three Iris species (I. ensata, I. ensata var. variegata, and I. sanguinea). The treatments included: A0 (control group), A1 (low concentration of 6-BA, 1,000 mg/L), A2 (high concentration of 6-BA, 2,000 mg/L), A3 (low concentration of PC, 500 mg/L), and A4 (high concentration of PC, 1,000 mg/L). Each bar represents an average (n = 12) ± standard error. The significant differences within each species compared to the A0 (control group) were analyzed using Tukey's HSD test following one-way ANOVA (* p < 0.05, ** p < 0.01, *** p < 0.001).

    • Figure 4. 

      Changes in key growth parameters of three Iris species (I. ensata, I. ensata var. variegata, and I. sanguinea) in response to plant growth regulator treatments. The most significant indicators identified from the dataset are presented. Treatments included two concentrations of 6-BA (1,000 and 2,000 mg/L), and PC (500 and 1,000 mg/L). Values represent the changes relative to the control.

    • Treatment Plant growth regulator Application concentration
      A0 − −
      A1 6-BA 1,000 mg/L
      A2 6-BA 2,000 mg/L
      A3 PC 500 mg/L
      A4 PC 1,000 mg/L
      6-BA, 6-Benzylaminopurine; PC, Prohexadione-Ca. Treatment A0 served as the control group, where plants were treated with distilled water. Each treatment received 1,000 mL per application on Oct. 30, Nov. 30, and Dec. 30, 2019, and on Jan. 30 and Feb. 29, 2020.

      Table 1. 

      Experimental treatments and application concentrations of PGRs.

    • Iris species Bud number Plant
      height
      in May      		 Plant
      height
      in June      		 Plant
      height
      in July      		 Plant
      height
      in Aug.      		 Plant
      height
      in Sep.      		 Plant
      height
      in Oct.      		 Number of
      flowers per
      plant      		 Flower
      stalk
      height      		 Increase in
      rhizome
      diameter      		 Rhizome
      weight
      Iris species 1 −0.062 0.152* −0.168* −0.538** −0.559** −0.649** −0.369** 0.835** −0.761** −0.045 −0.104
      Bud number −0.062 1 0.484** 0.271** 0.111 0.122 0.104 0.409** −0.568** 0.417** 0.370** 0.727**
      Plant height in May 0.152* 0.484** 1 0.612** 0.372** 0.297** 0.271** 0.317** −0.286** 0.252* 0.283** 0.501**
      Plant height in June −0.168* 0.271** 0.612** 1 0.675** 0.571** 0.548** 0.259** −0.315** 0.129 0.137 0.281**
      Plant height in July −0.538** 0.111 0.372** 0.675** 1 0.865** 0.899** 0.367** −0.455** 0.293** 0.137 0.163*
      Plant height in Aug. −0.559** 0.122 0.297** 0.571** 0.865** 1 0.872** 0.351** −0.499** 0.360** 0.128 0.174*
      Plant height in Sep. −0.649** 0.104 0.271** 0.548** 0.899** 0.872** 1 0.453** −0.528** 0.483** 0.149 0.198*
      Plant height in Oct. −0.369** 0.409** 0.317** 0.259** 0.367** 0.351** 0.453** 1 −0.564** 0.553** 0.192* 0.458**
      Number of flowers per plant 0.835** −0.568** −0.286** −0.315** −0.455** −0.499** −0.528** −0.564** 1 −0.688** −0.232* −0.544**
      Flower stalk height −0.761** 0.417** 0.252* 0.129 0.293** 0.360** 0.483** 0.553** −0.688** 1 0.229 0.357**
      Increase in rhizome diameter −0.045 0.370** 0.283** 0.137 0.137 0.128 0.149 0.192* −0.232* 0.229 1 0.520**
      Rhizome weight −0.104 0.727** 0.501** 0.281** 0.163* 0.174* 0.198* 0.458** −0.544** 0.357** 0.520** 1
      * Significant (p < 0.05), ** Highly significant (p < 0.01).

      Table 2. 

      Correlation analysis of growth indices and plant growth regulator treatments in wetland irises.

    • Treatments Bud
      number      		 Plant
      height
      in May      		 Plant
      height
      in June      		 Plant
      height
      in July      		 Plant
      height
      in Aug.      		 Plant
      height
      in Sep.      		 Plant
      height
      in Oct.      		 Number of
      flowers per
      plant      		 Flower
      stalk
      height      		 Increase in
      rhizome
      diameter      		 Rhizome
      weight
      Treatments 1 0.159 0.152 0.085 0.075 0.064 0.116 0.066 −0.027 −0.660* 0.020 0.051
      Bud number 0.159 1 0.421** 0.379** 0.310* 0.298* 0.314* −0.058 0.095 −0.481 0.099 0.354**
      Plant height in May 0.152 0.421** 1 0.849** 0.671** 0.660** 0.713** 0.060 0.103 −0.582 0.358** 0.383**
      Plant height in June 0.085 0.379** 0.849** 1 0.836** 0.753** 0.805** 0.109 0.152 −0.451 0.201 0.361**
      Plant height in July 0.075 0.310* 0.671** 0.836** 1 0.853** 0.937** 0.129 0.212 −0.538 0.166 0.306*
      Plant height in Aug. 0.064 0.298* 0.660** 0.753** 0.853** 1 0.891** 0.086 0.258 −0.512 0.172 0.296*
      Plant height in Sep. 0.116 0.314* 0.713** 0.805** 0.937** 0.891** 1 0.138 0.298 −0.588 0.118 0.282*
      Plant height in Oct. 0.066 −0.058 0.060 0.109 0.129 0.086 0.138 1 0.185 −0.122 −0.078 −0.097
      Number of flowers per plant −0.027 0.095 0.103 0.152 0.212 0.258 0.298 0.185 1 NA −0.012 0.088
      Flower stalk height −0.660* −0.481 −0.582 −0.451 −0.538 −0.512 −0.588 −0.122 NA 1 −0.436 −0.511
      Increase in rhizome diameter 0.020 0.099 0.358** 0.201 0.166 0.172 0.118 −0.078 −0.012 −0.436 1 0.540**
      Rhizome weight 0.051 0.354** 0.383** 0.361** 0.306* 0.296* 0.282* −0.097 0.088 −0.511 0.540** 1
      * Significant (p < 0.05), ** Highly significant (p < 0.01).
      NA indicates that it cannot be calculated because at least one variable is a constant.

      Table 3. 

      Correlation analysis of growth indices and plant growth regulator treatments in I. ensata.

    • Treatments Bud
      number      		 Plant
      height
      in May      		 Plant
      height
      in June      		 Plant
      height
      in July      		 Plant
      height
      in Aug.      		 Plant
      height
      in Sep.      		 Plant
      height
      in Oct.      		 Number of
      flowers per
      plant      		 Flower
      stalk
      height      		 Increase in
      rhizome
      diameter      		 Rhizome
      weight
      Treatments 1 −0.136 −0.171 −0.161 −0.512** −0.535** −0.477** −0.275* −0.038 −0.613** −0.027 0.291*
      Bud number −0.136 1 −0.186 −0.047 −0.126 −0.105 −0.159 0.063 −0.277 0.264 0.231 0.158
      Plant height in May −0.171 −0.186 1 0.733** 0.633** 0.630** 0.597** 0.350** −0.127 0.350 −0.414** −0.100
      Plant height in June −0.161 −0.047 0.733** 1 0.678** 0.615** 0.599** 0.423** −0.270 0.467* −0.282 −0.029
      Plant height in July −0.512** −0.126 0.633** 0.678** 1 0.745** 0.796** 0.667** −0.011 0.655** 0.005 0.035
      Plant height in Aug. −0.535** −0.105 0.630** 0.615** 0.745** 1 0.747** 0.416** −0.103 0.603** −0.142 −0.079
      Plant height in Sep. −0.477** −0.159 0.597** 0.599** 0.796** 0.747** 1 0.643** 0.196 0.624** 0 0.027
      Plant height in Oct. −0.275* 0.063 0.350** 0.423** 0.667** 0.416** 0.643** 1 0.167 0.639** 0.150 0.139
      Number of flowers per plant −0.038 −0.277 −0.127 −0.270 −0.011 −0.103 0.196 0.167 1 0.118 0.031 −0.148
      Flower stalk height −0.613** 0.264 0.350 0.467* 0.655** 0.603** 0.624** 0.639** 0.118 1 0.087 −0.274
      Increase in rhizome diameter −0.027 0.231 −.414** −0.282 0.005 −0.142 0 0.150 0.031 0.087 1 0.407**
      Rhizome weight 0.291* 0.158 −0.100 −0.029 0.035 −0.079 0.027 0.139 −0.148 −0.274 0.407** 1
      * Significant (p < 0.05), ** Highly significant (p < 0.01).

      Table 4. 

      Correlation analysis of growth indices and plant growth regulator treatments in I. ensata var. variegata.

    • Treatments Bud
      number      		 Plant
      height
      in May      		 Plant
      height
      in June      		 Plant
      height
      in July      		 Plant
      height
      in Aug.      		 Plant
      height
      in Sep.      		 Plant
      height
      in Oct.      		 Number of
      flowers per
      plant      		 Flower
      stalk
      height      		 Increase in
      rhizome
      diameter      		 Rhizome
      weight
      Treatments 1 0.116 −0.150 0.019 −0.181 −0.178 −0.343** −0.032 −0.119 −0.189 −0.521** −0.281*
      Bud number 0.116 1 −0.068 0.200 0.035 0.064 −0.104 −0.270* −0.142 0.059 −0.080 0.227
      Plant height in May −0.150 −0.068 1 0.190 0.513** 0.109 0.312* 0.270* 0.073 0.191 0.283 0.072
      Plant height in June 0.019 0.200 0.190 1 0.410** 0.103 0.203 0.014 −0.047 −0.071 0.044 0.239
      Plant height in July −0.181 0.035 0.513** 0.410** 1 0.720** 0.824** 0.248 0.164 −0.056 0.395* 0.489**
      Plant height in Aug. −0.178 0.064 0.109 0.103 0.720** 1 0.704** 0.231 0.209 −0.063 0.436* 0.466**
      Plant height in Sep. −0.343** −0.104 0.312* 0.203 0.824** 0.704** 1 0.429** 0.210 0.196 0.479** 0.545**
      Plant height in Oct. −0.032 −0.270* 0.270* 0.014 0.248 0.231 0.429** 1 0.078 −0.006 0.056 0.002
      Number of flowers per plant −0.119 −0.142 0.073 −0.047 0.164 0.209 0.210 0.078 1 0.007 0.196 −0.022
      Flower stalk height −0.189 0.059 0.191 −0.071 −0.056 −0.063 0.196 −0.006 0.007 1 0.054 −0.087
      Increase in rhizome diameter −0.521** −0.080 0.283 0.044 0.395* 0.436* 0.479** 0.056 0.196 0.054 1 0.661**
      Rhizome weight −0.281* 0.227 0.072 0.239 0.489** 0.466** 0.545** 0.002 −0.022 −0.087 0.661** 1
      * Significant (p < 0.05), ** Highly significant (p < 0.01).

      Table 5. 

      Correlation analysis of growth indices and plant growth regulator treatments in I. sanguinea.