Abstract
The spring phenology of juveniles of many canopy tree species in deciduous forests predates that of adult conspecifics. To determine whether the earlier phenology of seedlings of Aesculus glabra Willd. (Ohio buckeye) in Illinois, U.S.A., is developmentally or environmentally controlled, seedlings of five maternal parents were grown either in the understory or above a barn roof, simulating environmental conditions experienced at canopy height. Relative to canopy seedlings, understory seedlings had significantly earlier bud break (mean = 6 d), leaf expansion (8 d), leaf senescence (23 d), and leaf drop (18 d). Bud break and leaf expansion of canopy seedlings equalled that of canopy trees of Ohio buckeye, but senescence and leaf drop of canopy seedlings predated canopy trees by 45 and 67 d, respectively. Overall, results show evidence for environmental control over the spring phenology of juveniles. Thermal sums in spring accumulated more rapidly in the forest understory where nighttime temperatures were warmer than above the barn roof. Thus, the environmental control of spring phenology appears to be a non-stage-specific temperature cue that accumulates at different rates along the forest's vertical gradient. In contrast, senescence and leaf drop, while somewhat responsive to the environment, displayed strong developmental constraint.Key words: bud break, developmental constraint, leaf drop, leaf expansion, leaf senescence, thermal sums.
Publisher
Canadian Science Publishing
Cited by
19 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献