Plantlet morphology and the regulation of net water loss in tissue‐cultured Douglas‐fir

Abstract

Tissue‐culture plantlets of Douglas‐fir [Pseudotsuga menziesii (Mirb.) Franco] were highly susceptible to detrimental water loss upon removal from culture in vitro. Control of net water loss was related to shoot and root morphology. Relative water content after 3 h of atmospheric water stress was positively correlated to root number, root surface area, and the length of the longest root, and was inversely correlated to the ratio of needle surface area/root surface area. High relative water content apparently was a result of a higher rate of water uptake among plantlets with beneficial morphological features. It is recommended that, to improve the ability of a plantlet to withstand water stress during acclimatization, beneficial root system features be focused upon during plantlet production.