Hydraulic and Economical Traits in Short- and Long-Shoot Leaves of Ginkgo biloba Males and Females

Ginkgo biloba is a dioecious heterophyllous tree species with two leaf types. Short shoots always bear many leaves, which are undivided or slightly bilobed, but long-shoot leaves are smaller and are deeply divided into two or more lobes. To clarify the functional difference between the two leaf types, we investigated the morphology, anatomy, gas exchange, and hydraulic traits of the two leaf types in male and female trees. Our results showed that long-shoot leaves possessed a lower specific leaf area (SLA), higher leaf thickness, gas exchange rates, and average tracheid number than short-shoot leaves. When compared to short-shoot leaves, long-shoot leaves in male trees had higher leaf hydraulic conductance (K-leaf) and leaf water potential of 50% loss in K-leaf (leaf P50), while female trees exhibited relatively higher K-leaf. When comparing sexual differences, male trees possessed higher leaf thickness, leaf dissection index, vein density (VD), and predawn leaf water potential and lower SLA, tracheid number, and midday leaf water potential, while no significant difference in leaf P50 was observed between the two sexes. Male trees exhibited greater leaf gas exchange rates, which were tightly associated with other functional traits, such as VD and K-leaf. We found strong shoot-based and sex-related heterogeneities in the leaf hydrology, anatomy, and economy of Ginkgo biloba. Moreover, male ginkgoes may perform better due to their greater leaf hydraulic efficiency and gas exchange rates.

Automated summary

Ginkgo biloba is a dioecious heterophyllous tree species with two leaf types. Long-shoot leaves have lower specific leaf area (SLA) and higher leaf thickness, gas exchange rates, and average tracheid number compared to short-shoot leaves. Male trees have higher leaf hydraulic conductance (K-leaf) and leaf water potential of 50% loss in K-leaf (leaf P50) than short-shoot leaves, while female trees exhibit relatively higher K-leaf. Male trees also have greater leaf gas exchange rates, leaf thickness, leaf dissection index, vein density (VD), and predawn leaf water potential compared to female trees.