Population characteristics and growth status of Impatiens macrovexilla in heterogeneous habitats

【Objective】 The growth status，flower characteristics and population characteristics of wild population of Impatiens macrovexilla in heterogeneous habitats were investigated with the aim of providing a theoretical references for the growth status evaluation and protection of wild I.macrovexilla.【Method】A total of 18 wild populations of I.macrovexilla in Yangshuo County，Guilin were selected as investigation objects and their population size，basic habitat parameters，plant characteristics such as plant height，crown width and number of branches，and flowering characteristics such as flower color，size and quantity.A total of 14 quantitative indexes were recorded in detail to analyze the growth of I.macrovexilla in heterogeneous habitats in combination with soil nutrient content，habitat types and the interference of different species.【Result】The size of the 18 populations of I.macrovexilla varied greatly，with the number of populations ranging from 20 to >10000 plants and the area from 3 to >10000 m².Canopy density and soil depth in the habitats also differed.The plant height，crown width and branch number of different populations varied significantly，with the maximum being 3.23，3.13 and 7.50 times of the minimum，respectively.In terms of flowering characteristics，the differences in flower quantity could be more than 10 times，and flower length，flower width (flag petal width)，flower depth and wing petal width were significantly different among a few populations，with their maximum values 43.67%，27.73%，26.62% and 25.96% higher than their minimum values，respectively.The soil nutrient contents among different populations varied greatly，mainly due to human activities.Cluster analysis revealed that 11 out of the 18 populations possessed good comprehensive growth conditions，with Population 11 being the best and Population 17 the worst.The growth status much depended on habitat types.It was noted that human disturbance had effect on that growth of I.macrovexilla populations，but no obvious regularity was identified.【Conclusion】The plant height，crown width，number of branches and number of flowering are important parameters affecting population continuity and vary greatly among different populations of I.macrovexilla in heterogeneous habitats.As I.macrovexilla does not have high requirements on soil，this is not a primary factor affecting growth in I.macrovexilla populations.Population 11 exhibits the best overall performance and can be selected as an excellent germplasm resource for further development.