The Roles of the Cotyledons and Auxin in the Adventitious Root Formation of Hypocotyl Cuttings of Light-Grown Cucumber Seedlings

1969 ◽  
Vol 22 (5) ◽  
pp. 993-1000 ◽  
Author(s):  
Masayuki Katsumi ◽  
Yoshiko Chiba ◽  
Machi Fukuvama
Keyword(s):  
Adventitious Root ◽  
Root Formation ◽  
Adventitious Root Formation ◽  
Cucumber Seedlings ◽  
Hypocotyl Cuttings

Effect of polar auxin transport and gibberellins on xylem formation in pine cuttings under adventitious rooting conditions

2020 ◽  
Vol 67 (1-2) ◽  
pp. 27-39 ◽  
Author(s):  
Alberto Pizarro ◽  
Carmen Díaz-Sala
Keyword(s):  
Adventitious Root ◽  
Root Formation ◽  
Auxin Transport ◽  
Adventitious Rooting ◽  
Adventitious Root Formation ◽  
Polar Auxin Transport ◽  
Root Induction ◽  
Xylem Differentiation ◽  
Xylem Formation ◽  
Hypocotyl Cuttings

Maturation-related decline of adventitious root formation is one of the major factors affecting adventitious rooting in forest tree species. We demonstrate that inhibition of polar auxin transport promoted cambium and xylem differentiation in rooting-competent hypocotyl cuttings from Pinus radiata under conditions of adventitious root formation. Treatments with bioactive gibberellins inhibited rooting while at the same time inducing both the differentiation of a continuous ring of cambium and xylem formation. Treatments with inhibitors of gibberellin biosynthesis did not affect the rooting response. The results demonstrate that xylem parenchyma and procambial cells at the xylem poles of rooting-competent hypocotyl cuttings after excision and under conditions of adventitious root induction become adventitious root meristems or xylem, depending on the directional auxin flow. Gibberellin may interact with this pathway, inducing xylem differentiation and inhibiting rooting. We conclude that modifications of auxin flow at the rooting sites, and the priming of cambial cells to differentiate into xylem during tree ageing, may be associated with the maturation-related decline of adventitious root formation.

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