Rapid leaf trait response to growing-season meteorology inVitis:Implications for leaf physiognomic paleoclimate reconstructions

Abstract

18PREMISE OF THE STUDY: The size and shape (physiognomy) of woody, dicotyledonous 19 angiosperm leaves are correlated with climate and these relationships have been used to develop 20 paleoclimate proxies. These proxies assume that leaf morphology plastically responds to 21 meteorological conditions and that leaf traits change isometrically through development. 22 METHODS:We used Digital Leaf Physiognomy (DiLP) to measure leaf characters of multiple 23Vitis species from the USDA Germplasm Repository in Geneva, NY from the 2012-2013 and 24 2014-2015 growing seasons. These growing seasons had different temperature and precipitation. 25 KEY RESULTS: We found three primary results: (1) there were predictable significant 26 differences in leaf characters in leaves of different developmental stages along the vine, (2) there 27 were significant differences in leaf characters in leaves of the same developmental stage between 28 the growing seasons, and (3) there were significant differences in leaf characters between 29 growing seasons. 30 CONCLUSIONS:We found that Vitis leaf shape had the strongest relationship with growing 31 season meteorological conditions in taxa growing in their native range. In addition, leaves have 32 variable phenotypic plasticity along the vine. We interpret that the meteorological signal was 33 strongest in those leaves that have completed allometric expansion. This is significant for leaf 34 physiognomic-paleoclimate proxies because these leaves are most likely to be preserved in leaf 35 litter and reflect the type of leaves included in paleoclimate reconstructions. We found that leaf 36 development does have the potential to be a confounding factor, but it is unlikely to exert a 37 significant influence on analysis due to differential preservation potential. 38 39 Keywords: paleoclimate proxy, phenotypic plasticity, Vitis, leaf development, leaf physiognomy 40 41 <d<e, <d<f; Wing and Greenwood, <ddD; Wolfe, <ddD; Wilf, <ddg; Wilf et al., <ddh; Jacobs, <ddd, 46 @cc@; Gregory-Wodzicki, @ccc; Adams et al., @cch; Peppe et al., @c<<). Angiosperm leaves 47 riparia has the widest range and spans from southern Canada to the Gulf of Mexico and from the 132 Rocky Mountains to the Atlantic Ocean; the collection area is within its native geographic range. 133 V. aestivalis spans from the northern United States to southern Texas and from Great Plains to 134 the Atlantic Ocean, with the collection site being within its native geographic range. V. acerifolia 135 spans from central Great Plains to northern Mexico and from the western Great Plains to the Gulf 136 of Mexico. The collection area for this species is outside of its native geographic range. The 137