FOLIAR RAFFINOSE AND SUCROSE IN 4 CONIFER SPECIES - RELATIONSHIP TO SEASONAL TEMPERATURE

Foliar raffinose and sucrose concentrations in eastern white pine (Pinus strobus L.), eastern redcedar (Juniperus virginiana L.), Leyland cypress (xCupressocyparis leylandii Dallim.), and Virginia pine (Pinus virginiana L.) were measured monthly over 2 years. During cold weather, foliage of white pine and redcedar contained higher concentrations of raffinose and sucrose than did Leyland cypress and Virginia pine. Raffinose concentrations were highest during winter and were best correlated with the frequency of occurrence of daily minima less-than-or-equal-to 1.7C during the 30 days before sampling. Sucrose concentrations, which also reached maximum levels during the winter, were best correlated with the frequency of occurrence of daily minima less-than-or-equal-to 7.2C in the prior 30 days. Sucrose concentrations were relatively high during fall and spring. Raffinose and sucrose concentrations increased in response to recurring low temperature, with correlations highest for raffinose.