Js. Kuehny et al., CHANGES IN CARBOHYDRATE AND NITROGEN RELATIONSHIPS DURING EPISODIC GROWTH OF LIGUSTRUM-JAPONICUM THUNB, Journal of the American Society for Horticultural Science, 122(5), 1997, pp. 634-641
Rooted cuttings of Ligustrum japonicum Thunb., an episodically growing
species, were-grown hydroponically in a controlIed-environment growth
chamber to determine allocation of glucose, mannitol, total soluble s
ugars, and total protein in mature leaves, flush leaves, stems, and ro
ots, During the 65 days of episodic growth, 43% of the total soluble s
ugars was glucose and 33% mannitol. Glucose concentrations of mature l
eaves decreased during the first root growth episode, increased in alm
ost all plant tissue during a shoot growth episode and decreased in al
l plant tissue at initiation of a second root growth episode. Mannitol
concentrations in the roots and stems decreased during episodes of ro
ot growth and increased during a shoot growth episode when leaf flush
mannitol concentrations increased. Radiolabeled C applied to leaves be
fore thr initiation of the first period of shoot elongation was transl
ocated to the roots. After shoot elongation, just before a root growth
episode, most labeled C was translocated to new shoots and roots, Aut
oradiographs indicated that subsequent episodes of shoot growth were s
upported by photosynthate from the previous shoot flush, Protein conce
ntrations decreased in all plant tissues during shoot growth but incre
ased in roots and mature leaves during root growth. Concentrations of
N-15 in leaf and stem tissue indicated retranslocated N supported each
episode of shoot growth. Changes in endogenous and N concentrations a
nd allocation patterns in ligustrum were linked to the control of epis
odic shoot and root growth.