热带园林灌木翅荚决明对水分胁迫的生长响应

Growth Response of Tropical Landscape Shrubs Senna alata to Water Stress

摘要:

华南地区强季节性降雨导致植物频繁遭受水分胁迫，滨水区园林植物选择与应用成为海绵城市建设的关键问题。为探究滨水区热带园林植物的形态响应策略，对翅荚决明(Senna alata)幼苗在持续水淹、持续干旱和旱涝交替3种水分胁迫下的叶性状、根系性状和生物量分配等进行测量。结果表明，水分胁迫对翅荚决明叶面积、叶厚度、比根长、根组织密度、根生物量和叶生物量等15个指标均存在显著影响(P<0.05)。持续水淹对叶性状影响较大，根系性状对持续干旱更为敏感，旱涝交替胁迫对翅荚决明的叶性状、根系性状和生物量影响较小，水分胁迫对直径为0.50 mm≤d<2.00 mm的根系影响最为显著。翅荚决明叶-根系性状间存在一定的相关性；水分胁迫下，翅荚决明生长策略倾向于缓慢投资收益型。因此，翅荚决明对旱涝交替胁迫的适应性更好，宜于滨水绿地、雨水花园等可能出现旱涝交替胁迫的城市绿地推广应用。

Abstract:

The strong seasonal rainfall in south China frequently subjects plants to water stress, making the selection and application of water-edge garden plants a key issue in the construction of sponge cities. To explore the morphological response strategies of tropical garden plants in water-edge areas, the leaf traits, root traits and biomass allocation of Senna alata seedlings under three water stress conditions, namely continuous flooding, continuous drought and alternate drought and flooding, were measured. The results showed that water stress had a significant impact on 15 indicators including leaf area, leaf thickness, specific root length, root tissue density, root biomass and leaf biomass of S. alata (P<0.05). Continuous flooding had a greater impact on leaf traits, while root traits were more sensitive to continuous drought. Alternate drought and flooding stress had a relatively small impact on the leaf traits, root traits and biomass of S. alata. The impact of water stress on roots with a diameter of 0.50 mm≤d<2.00 mm was the most significant. There was a certain correlation between the leaf and root traits of S. alata. Under water stress, the growth strategy of S. alata tended to be slow investment and return type. Therefore, Senna alata has better adaptability to alternate drought and flooding stress and is suitable for promotion and application in urban green spaces such as water-edge green spaces and rain gardens where alternate drought and flooding stress may occur.