兰州市主要绿化植物气孔性状特征

气孔是植物叶片与外界环境进行水汽交换的门户, 利用气孔特征反映植物对环境变化的响应与适应有助于了解干旱区绿化植物的适应策略。于2019年7月通过气孔印迹法对兰州市40种主要绿化植物气孔性状进行观察与测定。采用标准化主轴估计和系统独立比较分析建立气孔性状间的相关关系; 通过计算Blomgerg’sK值以检验系统发育信号; 利用聚类分析和主成分分析对气孔性状特征进行功能群划分。结果表明: (1)在所研究的植物中, 气孔性状特征在个体间差异显著, 植物生长型(乔木、小乔木、灌木和草本)会显著影响气孔长度、宽度、开度和密度, 叶习性(落叶和常绿)仅对气孔开度有显著影响; (2)气孔长度与宽度、气孔开度与面积间均为显著的异速生长关系, 气孔密度与面积和开度间为负异速生长关系; (3)系统发育会对气孔性状的相关关系产生显著影响, 虽然气孔性状的系统发育保守性不强(K < 1), 但气孔开度和气孔开张比具有显著的系统发育信号; 4)依据气孔性状特征可以将绿化植物划分为: 低密度-大面积、高密度-小面积和中等密度-适中面积共3种功能群。结合系统发育和异速生长理论能更好地解释气孔性状变异及适应策略。

Stomatal traits of main greening plant species in Lanzhou

Aims Stomata are the main channels for water and gas exchange between plants and the atmosphere. Stomatal traits reflect plant responses to environmental changes, and thus could help us better understand plant adaptation strategies to arid environments.Methods In July 2019, six traits for stomata were measured from 40 main greening plant species in Lanzhou, Gansu Province. One-way ANOVA was used to test the traits difference among the growth forms (tree, semi-tree, shrub and herb) and leaf habits (deciduous and evergreen). Standardized major axis estimation and phylogenetically independent contrast analysis were used to compare the allometry relationship between stomatal traits. Then the Blomberg’sK value was calculated to determine phylogenetic signal. Functional groups were partition by k-means clustering and principal component analysis.Important findings The stomatal traits varied significantly among greening plant species. Different growth forms (trees, semi-trees, shrubs and herbs) showed significant variations in stomatal length (SL), width (SW), opening level (SOL) and density (SD), while deciduous and evergreen plants only differed in SOL. Significant allometric relations were detected between SL vs. SW, SOL vs. SA. We also observed negative allometric relations between SD vs. SA and SD vs. SOL. Phylogeny significantly influenced the correlations among stomatal traits. Although the phylogenetic conservatism of stomatal traits was not strong (K< 1),SOL and stomatal opening ratio (SOR) showed significant phylogenetic signals (p < 0.05). According to the stomatal traits, greening plants can be divided into three functional groups: lower-density with larger area, higher-density with smaller area, or medium- density with moderate area. The combination of phylogeny and allometric scaling relations can provide a better explanation for stomatal trait variations and adaptation strategies.