Asexual Propagation of Juniperus Procera Hochst. Ex Endl. Through Rooting of Branch Cuttings
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Date
1997-06
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Addis Ababa University
Abstract
The rooting responses of branch cuttings of Juniperus procera Hochst. ex Endl., obtained from
juvenile and mature source plants to foul' plant growth regulators (PGRs), namely, indole-3-acetic
acid (IAA), indole-3-butydc acid (lBA), naphthaleneacetic acid (NAA), and 2,4-
dichlorophenoxyacetic acid (2,4-D) at vadous concentrations (lrrJ to lrr9 iW) were examined ill sand
culture. Assessments 011 survival, callusing and rooting of the cuttings were conducted 16 and 32
weeks after the treatments. Odgin of root primordia was examilled microscopically, amI
establishment and perfonnance of stecklil;gs were done 011 sample rooted cuttings. It was found that
the developmental stage of the source plants from which the cuttings were derived, and the type, as
well as the cOllcentratioll of the PGR, markedly affected the survival of the cuttings. About 77% of
the cuttings obtained from Class 111 source plants (mature) died out withill the first 30 days after
treatment; while 34% of the cuttings obtained from Class 11 (mature), and 90% of the cuttings
obtained from Class I source plants (juvenile) survived until the end of the investigatioll. Callusing
and rootillg of the cuttings were greatly affected by the developmental stages of the source plants.
Sixteen weeks after treahnent, meall percentage callusillg of cuttillgs obtained from Class I source
plants was significantly greater thall that obtailled from Class 11 source plants (p ,:; 0.05). The
highest attainable percelltage of callused cuttings obtained from Class I source plants was 56, treated
at 10-' 1'vlIAA and lrrs lW NAA. The corresponding percentage for the cuttillgs obtained from Class
II source plants was 29, treated at 10-' M IBA. At this time, ollly 2% of the cuttings obtained from
Class 1 source plants were rooted. Thirty two weeks after treatment, 24% of the cuttings obtained
from Class 1 source plants were rooted. By this time, only a single cutting from Class II source
plants rooted. The highest attainable percentages of rooted cuttings obtailled from Class I source
plallts was 60 treated at 1 rr7 1'1'1 IAA. The cOlrespondillg percentages were 50, 44 and 25 for NAA
(treated at 1rrJ J'rI), IBA (h'eated at lrrs 1'vI) alld 2,4-D (treated at 10-' and lrr7 M), respectively. The
control resulted in 29% rooting. The melli/maximum attainable root numbers pel' rooted cuttings in
IAA (treated at 10-' iW), IBA (h'eated at 1rr3 M), 2,4-D (treated at lrr9 M) and NAA (treated at lrrs
i',I) were 17.0 ± 4.1, 14.5 ± 12.5, 9.7 ± 6.7 and 7.0 ± 3.0, respectively. The mean root number
per rooted cuttings ill the conh'ol was 17.0 ± 1.7. The highest attainable mellll root length was 372
± 51.5 mm, for cuttillgs treated at lrrJ M NAA. The correspollding values for IBA (h'eated at lrr3
M), IAA (treated at 10-' M) and 2,4-D (treated at 10-' M) were 113.7 ± 11.7mm, 90.7 ± 5.6 mm
and 67.7 ± B.B 111m, respectively. The /IIean root length of the cuttillgs rooted ill the cOllh'ol was
93.9 ± 7.3 /11m. Regression analysis showed that the cOllflibution of callusing to rootillg is velY
small (Rt = 0.2070, P ,:; 0.05). III this species, cells of callus tissue, xylem rays, trach~ids, c011ex
alld cambium resulted ill the fonnatioll root primordia. Stecklings with well developed root systems
were easily established and grew well, indicatillg the possibility of propagating the species by asexual
means.
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Biology