The effect of a seaweed application on the rooting of pine cuttings

Seaweed extracts are known to have stimulatory effects on the growth and development of plants. This study investigated the root promoting properties of a commercial seaweed preparation on conifer cuttings. Various concentrations of Kelpak were used as an initial application to the bases of Pinus patula cuttings for differing time intervals during summer and early autumn. While the cuttings treated in summer showed very poor rooting, the effects of the Kelpak treatments on the autumn-set cuttings were more pronounced. High (1:1) and low (1:100) concentrations of Kelpak generally resulted in a lower rooting percentage with the former treatment also producing poor root development. The most successful treatments; producing up to 70% rooting; were those in which cuttings were exposed to an intermediate level of Kelpak (1:10) for 1 to 12 h prior to establishment in the rooting medium. In these treatments, not only did the percentage rooting increase over and above that of the controls, but rooting quality also improved, resulting in the development of a vigorous root system consisting of numerous lateral roots. Anatomical studies, conducted to ascertain whether a functional vascular system had developed between the root and the shoot, indicated that this was the case, even in treatments where rooting quality was poor.