As a highly resistant urban ornamental plant, Elaeagnus angustifolia L. is often used in dry land, saline-alkali land shelter forest, and landscape horticulture. It is the main windbreak and sand-fixing tree species in Gansu Province, China. The special geographical and climatic environment makes the distribution and growth of E. angustifolia in Gansu Province show different degrees of difference. In order to evaluate the phenotypic diversity of E. angustifolia in different populations and its variation patterns under different geographical and climatic conditions, 35 phenotypic traits (trunk, branch, leaf, and flower related traits) of 90 plants from 10 populations in Gansu Province were measured and analyzed. The results showed the following: (1) E. angustifolia has rich phenotypic variation. The variation is greater among populations. The traits with the largest and smallest coefficients of variation were “under-branch height” and “flower diameter”, respectively. The variation in the Qilihe population was the largest, and the variation in the Ganzhou population was the smallest. The diversity of flowers and leaves is relatively higher. (2) Correlation analysis showed that most of traits were closely related. Leaf traits showed a gradient variation law dominated by altitude and precipitation. Flower traits were affected by the synergistic effects of various geographical and climatic factors. (3) The results of the principal component analysis (PCA) showed that the primary traits affecting the phenotypic diversity of E. angustifolia were leaf size and branch length among the related traits of trunk, branch, leaf, and flower. (4) Cluster analysis showed that 90 E. angustifolia plants were clustered into four clusters that were not completely clustered according to geographical distance and may be randomly affected by genotypic or environmental factors. These results will lay a foundation for further analysis of the genetic mechanism of phenotypic traits of E. angustifolia and also provide a reference for the collection, preservation, and variety improvement of E. angustifolia germplasm resources.

Plants of the Clematis genus are attractive ornamental plants due to their various flower colors and patterns, and they play an important role as ground cover plants in landscaping. However, the application of Clematis plants in landscaping in arid and semi-arid areas is limited. This study used five common wild Clematis species in Gansu Province as experimental materials, including Clematistangutica, Clematis glauca, Clematis intricata, Clematis nannophylla, and Clematis fruticosa. By simulating different intensities of drought stress with polyethylene glycol (PEG), the germination behavior of seeds and the physiological and biochemical responses of seedlings of these five species to drought stress were observed. The results showed that 15% PEG stress significantly inhibited the seed germination of the five species, which was also the drought threshold for seed germination of C. fruticosa. C. tangutica exhibited the strongest tolerance to drought stress in seed germination. Seedlings of the five Clematis plants showed different levels of tolerance to drought stress, mainly demonstrating higher tolerance to 10% and 20% concentrations of PEG stress, while a 30% concentration of PEG stress caused varying degrees of damage to the seedlings of the five Clematis species. PCA analysis indicated that seedlings of C. intricata and C. glauca had higher scores under drought stress. These findings can provide a theoretical basis for the selection of urban landscaping plant species in arid and semi-arid regions of northwest China.

Elaeagnus angustifolia L. is a highly adaptable urban ornamental plant, playing a key role in dry land and saline-alkali protective forests. The diverse geographical and climatic conditions in Gansu Province have resulted in variations in its distribution and growth. This study assesses the phenotypic diversity of fruits and seeds, and the seed germination characteristics of 82 E. angustifolia plants from nine populations in Gansu Province, exploring their relationship with geographical and climatic factors. We measured 12 phenotypic traits and five germination indices. This study included germination tests under standard conditions, statistical analysis of phenotypic differences, and Pearson and Spearman correlation analyses to examine relationships between traits and geo-climatic factors. Principal component and cluster analyses were also performed to identify key traits and classify populations. The findings were as follows: (1) Significant differences were observed in phenotypic traits and germination characteristics among populations. Single fruit weight showed the highest variation (27.56%), while seed transverse diameter had the lowest (8.76%). The Lanzhou population exhibited the greatest variability (14.27%), while Linze had the lowest (6.29%). (2) A gradient change pattern in traits was observed, primarily influenced by longitude and a combination of geographical and climatic factors. Seed germination was positively correlated with altitude, annual precipitation, and relative humidity, but negatively affected by latitude and traits such as fruit weight. (3) Principal component analysis identified germination rate, germination index, seed shape index, and fruit shape index as primary factors, contributing 27.4%, 20.6%, and 19.9% to the variation, respectively. Cluster analysis grouped the 82 plants into four clusters, not strictly based on geographical distance, suggesting influence from factors such as genotype or environmental conditions. In conclusion, this study lays a foundation for understanding the genetic mechanisms behind the phenotypic diversity and germination characteristics of E. angustifolia. It offers insights into how geo-climatic factors influence these traits, providing valuable information for the species’ conservation, cultivation, and management.

Soil salinization severely restricts vegetation restoration in Northwest China. Native Limonium plants, capable of naturally colonizing saline-alkalisaline–alkali wasteland, are potential germplasm for low-cost ecological restoration. This study focused on three wild Limonium species (Limonium aureum, Limonium bicolor, Limonium gmelinii) in Gansu Province. In this study, we integrated seed phenotypic diversity with stress tolerance. We then investigated seed germination indices (e.g., germination rate, energy, vigor index) and seedling physiological–biochemical indices of three Limonium species under 0, 100, 200, 300 mM NaCl and NaHCO₃ stress. These indices included leaf and root Na⁺ and K⁺ contents, chlorophyll a and b and carotenoid contents, and malondialdehyde (MDA), proline, soluble sugar, and soluble protein contents, plus SOD and CAT activities. Results showed seed area and thickness were key to germination performance, with L. aureum having the largest and thickest seeds and strongest germination potential. The onset concentration of significant inhibition for salt/alkali was 200 mM. At the seedling stage, L. aureum performed best at 100–200 mM, while all three were damaged at 300 mM. Principal component analysis indicated that L. aureum had the highest comprehensive scores under both NaCl and NaHCO₃ stresses, while L. bicolor and L. gmelinii presented distinct stress-specific adaptation differences. Thus, L. bicolor is recommended for salt-dominated soils and L. gmelinii for alkaline environments, and L. aureum can be used for mildly heterogeneous habitats. This study clarifies inter-species differences under stress, providing a direct theoretical basis for ecological restoration in saline–alkali areas.