Photosynthesis and Growth Responses of Parthenocissus quinquefolia (L.) Planch to Soil Water Availability

Photosynthesis and growth characteristics of Parthenocissus quinquefolia were measured under differing soil water availability within a pot. Decreased soil moisture significantly reduced the leaf relative water content (RWC) and the above- and below-ground biomass. However, more biomass was allocated to the root than to the leaf. Net photosynthetic rate (P_N), stomatal conductance (g_s), and transpiration rate (E) were also significantly decreased but water use efficiency (WUE) was increased. Midday depressions in P_N and g_s were not evident for the well-irrigated plants. With the lower water availability, midday reductions in P_N and g_s were much more marked and the duration of the depression was longer. Additionally, the P_N-irradiance response curves also indicated that water supply affected photosynthesis capacity. The growth and photosynthetic response of P. quinquefolia to water supply indicated that this species could resilient to water availabilities and adapt to Hunshandak conditions very well.