Indole-3-butyric acid accelerates adventitious root formation and impedes shoot growth of Pinus elliottii var. elliottii?×?P. caribaea var. hondurensis cuttings

Many plantation tree species are cloned to achieve the growth, disease resistance and wood quality characteristics required for a successful economic venture. However, clonal propagation is limited by declines in adventitious root formation with increasing stock plant age. We examined the effects of immediate or delayed IBA application on adventitious root formation and subsequent root and shoot development of cuttings harvested from 8-year-old clonal hedge plants of Pinus elliottii var. elliottii × P. caribaea var. hondurensis. IBA applied at the time of setting accelerated root formation, elevating the percentage of cuttings with roots at 13 weeks post-setting from 45 to 78% and from 83 to 93% for a low- and a high-rooting clone, respectively. Final rooting percentages for the same treatments and clones (78 and 85%, and 88 and 100%, respectively, at 20 weeks post-setting) were not significantly affected by IBA application. IBA increased the root:shoot ratio of rooted cuttings by decreasing shoot weight compared with untreated cuttings, without affecting root weight, root length, root surface area or root volume. IBA was only effective when applied at the time of setting. A simple IBA treatment for cuttings from 8-year-old clonal hedges, by accelerating root production, has potential for reducing nursery costs and increasing the root system quality of containerised pine cuttings.     

Emissions of saturated C6-C10 aldehydes from poplar(Populus simonii×P.pyramidalis ‘Opera 8277’) cuttings at different levels of light intensity

Aldehydes play an important role in atmospheric chemistry and plant direct and indirect defense against environmental stresses.In this study,the emissions of saturated C6-C10 aldehydes from Populus simonii × P.pyramidalis 'Opera 8277' cuttings were examined by using a gas chromatography/mass spectrometry(GC/MS) technique at three levels of light intensity(400,800 and 1 200 μmol·m-2·s-1).A positive correlation between the emissions of these aldehydes and light intensity was found.Moreover,nordi-hydroguaiaret...