Greenwood M S, Weir R J
University of Maine, 5755 Nutting Hall, Orono, ME 04469-5755, USA.
Tree Physiol. 1995 Jan;15(1):41-5. doi: 10.1093/treephys/15.1.41.
After about 20 days, hypocotyl cuttings from 20-day-old loblolly pine (Pinus taeda L.) seedlings rooted easily in the presence of the auxin indole-3-butyric acid (IBA), with roots forming directly from xylem parenchyma. In contrast, woody cuttings from 1-2-year-old hedged seedlings formed roots indirectly from callus tissue in 60-90 days, but IBA had little effect on rooting. Variation in rooting among hypocotyls from both half- and full-sib families was highly significant in response to IBA, and rooting did not occur within 20 days unless IBA was applied. Hypocotyls from poor rooting families tended to produce fewer roots per cutting than hypocotyls from good rooting families. Rooting by woody cuttings and hypocotyl cuttings from the same nine full-sib families was weakly correlated, raising the possibility that at least some common genetically controlled processes were affecting rooting by both types of cutting. The phytotropin N-1-naphthylphthalamic acid (NPA), supplied at 1 micro M with 10 micro M IBA, significantly inhibited rooting by hypocotyl cuttings from both good and poor rooting families, but there was no significant family x treatment interaction. Family variation in rooting ability may be a function of the frequency of occurrence of auxin-responsive cells in the hypocotyls.
约20天后，20日龄火炬松（Pinus taeda L.）幼苗的下胚轴插条在生长素吲哚 - 3 - 丁酸（IBA）存在的情况下很容易生根，根直接从木质部薄壁组织形成。相比之下，1 - 2年生绿篱苗的木质插条在60 - 90天内从愈伤组织间接形成根，但IBA对生根影响很小。来自半同胞和全同胞家系的下胚轴在生根方面对IBA的反应差异非常显著，并且除非施用IBA，否则在20天内不会生根。生根较差家系的下胚轴每插条产生的根往往比生根良好家系的下胚轴少。来自相同九个全同胞家系的木质插条和下胚轴插条的生根情况相关性较弱，这增加了至少一些共同的基因控制过程影响两种插条生根的可能性。以1微摩尔/升与10微摩尔/升IBA一起供应的植物生长素N - 1 - 萘基邻苯二甲酸（NPA）显著抑制了来自生根良好和生根较差家系的下胚轴插条生根，但没有显著的家系×处理交互作用。生根能力的家系差异可能是下胚轴中生长素反应性细胞出现频率的函数。
