The effects of exogenous IAA and GAs on phloem and xylem production in Pinus sylvestris and Picea abies
Cui, K.M.; Little, C.H.A.
Chinese Journal of Botany 5(2): 145-153
IAA significantly promoted xylem and phloem production, and its effect is more prominant in the top than in the middle of the cuttings in Pinus sylvestris L. and Picea abies L. GAs significantly inhibited xylem production in Picea abies L. However, the effects of GAs on phloem production were inconsistent. GA-3 is more effective on phloem production than GA-4/7 or GA-9. GA-3 also has significant effect on the component proportion in the newly formed phloem. The highest percentage of the parenchyma cells in phloem was demonstrated when the debudded cuttings were treated with GA-3 or GA-9. The original cell morphological feature of cambial zone was lost bemuse the transverse division occurred in the cambial fusiform initials in the debudded cuttings treated with lanolin alone or with GA-3 or GA-9.