Xylem vessel traits predict the leaf phenology of native and non-native understory species of temperate deciduous forests

Non-native understorey woody species have been shown to extend leaf display and inhabit vacant phenological niches in early spring and late autumn when growing with native counterparts in temperate deciduous forests across the world. Despite the potential competitive advantages, extended leaf duration also subjects non-native species to possible hydraulic risks associated with maintaining leaves during periods of increased frost probability. It remains unclear how non-native species are able to maintain xylem function within this context. Leaf phenology in temperate deciduous trees has been shown to be a function of xylem anatomy, with earlier bud break associated with smaller xylem vessels due to the presumed resistance of smaller vessels to freezing-induced cavitation. We examined relationships between leaf phenology and xylem vessel traits across 82 native and non-native understorey deciduous woody species common to eastern U.S. deciduous forests. We hypothesized that non-native sp...

全球温带落叶林生态系统中，非本土林下木本植物与本土同类伴生时，已被证实可延长叶片展期，并占据早春与晚秋的空物候生态位（phenological niche）。尽管这可能带来竞争优势，但延长的叶片展期也会使非本土物种面临与在霜冻概率升高时段维持叶片相关的潜在水力风险（hydraulic risk）。目前尚不清楚在此情境下非本土物种如何维持木质部（xylem）功能。
温带落叶树的叶片物候（leaf phenology）已被证实与木质部解剖结构相关：由于学界普遍认为小型木质部导管（xylem vessel）更能抵御冰冻诱导的空穴化（cavitation），因此萌芽更早的树种往往具有更小的木质部导管。本研究针对美国东部落叶林常见的82种本土与非本土林下落叶木本植物，分析了叶片物候与木质部导管性状之间的关联。我们提出假说：非本土物种……