Short-day treatment enhances root egress of summer-planted Picea abies seedlings under dry conditions

Abstract

Second year Norway spruce [Picea abies (L.) Karst.] container seedlings, short-day (SD) treated for 3 weeks in July, were exposed together with untreated control seedlings (Co) to three different drought treatments for 5 weeks after planting in early August. The treatments were: (1) regular watering (0 week drought); (2) 2 weeks of drought and 3 weeks of watering; and (3) no watering (5 week drought). No difference was found in the vigour and shoot xylem water potential between the SD-treated and the Co seedlings after the drought treatments. The root growth decreased less for the SD seedlings than for the Co seedlings along with the increase in the length of the drought period.