5种蕨类植物的羽片与叶柄水力协调研究OA

To explore the hydraulic coordination mechanism between leaflets and petioles of ferns,the pressure-volume curves of leaflets of five fern species(Cyclosorus interruptus,Diplazium donianum,Nephrolepis cordifolia,Psilotum nudum and Pteris vittata)were measured,and the correlations between the morphological structures of leaflets and petioles and their hydraulic functions were analyzed.The results showed that the hydraulic efficiency[theoretical water conductivity of leaflets(Kleaf)and theoretical water conductivity of petioles(Kth)]and the hydraulic safety[water potential at the loss of turgor pressure(Ψtlp)]of Pteris vittata were higher than those of other species.The pinnae of D.donianum exhibited the highest water storage capacity[absolute water capacity(CT)and saturated water content(SWC)],but its safety was the lowest.Diplazium donianum had the most dense and smaller stomata and the highest minimum leaf surface conductance(gmin),while Psilotum nudum had the most sparse and larger stomata.The maximum theoretical stomatal conductance(gs,max)of Pteris vittata was higher than that of other species.The supply and consumption of water by petioles and leaflets of ferns were coordinated.The water supply function of petioles was significantly correlated with the stomatal traits.Higher Kth was accompanied by smaller and denser stomatal distribution and larger gs,max.In addition,gs,max was significantly positively correlated with the area of xylem in petiole)(P<0.05),and gmin is significantly positively correlated with SWC(P<0.05).The hydraulic efficiency was coordinated with hydraulic safety in pinnae(P<0.01),meaning that pinnae with higher Kleaf have more negative Ψtlp.This revealed the hydraulic coordination mechanism between pinnae and petioles of ferns,indicating that ferns achieve a dynamic balance between water transport efficiency and transpiration demand through structural-functional coordination.This adaptive strategy might enhance their adaptability to the environment.