Acaia Byssinica Hochst. Exbenth: Pod and Seed Characteristics, Germination Physiology and Potentials for Seedling Establishment on Degraded Land
No Thumbnail Available
Date
1998-06
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Addis Ababa University
Abstract
This study was conducted on pod and seed characteristics, gel1ninalion physiology as well as the potentials of
Acacia abyssinica Hochst. ex Benlll ssp. abyssinica fOI' growing on degraded land. Mature pods of A. abyssinica
were collected ji'01/l Irees found in alld around Addis Ababa (wilhin a radius of 35 km). One hundred pods pel' tree
were collected ji'on, 26 diJ)erellt frees. Comparison of the lIIeans of pod lenglh, pod widlh and seed nUlllber per
pod showed Significant dij)erences (p < 0.05) among samples obtained ji'om the dij)erent localities. Pod lenglh,
pod width and number of seeds per pod ranged between 3.7 and 14.4 cm, 1.0 and 2.7 CIII and 2 and 13
respeclively. 11lere was no significant correlation benveen pod lenglh and widlh. Pod lenglh and number of seeds
per pod were significanlly correlated (p ~ O. OOO). On the other hand, pod widlh and number of seeds pel' pod were
negalively cOI1'elaled (p ~ 0.000). Seeds collecled ji'om 35 dij)erent h'ees were made into 17 bulks (each
containing 1000 seeds). 111e weight oflhe bulks ranged ji'om 74.01 to 116.11 g. There were significant dij)erences
(p ~ O. OOO) among Ihe mean weights of the 17 seed bulks.
E.Dects of gibberrelic acid (GA;I, indole-3-aceclic acid (lAA) and kinetin wilh concenh'alions ranging ji'01n 1IJ'
M to 11J7 JIIi on percentage gennination and radicle length of chemically scarified seeds ofA. abyssinica were
exall/ined None of Ihe plant growth regulators significantly increased Ihe total percenlage gel1l1ination of seeds
as compared to the control. Gennination percentage decreased Significantly at higher concenh'ations of fAA (IIJ'
,vi and 10-' Ai) and kinetin (I (f' ill!). 1AA at 11J' }.i delayed genllination for aboul a week as compared to the other
concenh'alions of the same, Ihough 63% of the seeds genllinated wilhin 10-15 days after incubalioll. GA, (at 11J'
ill!) Significantly increased radicle length, while 1AA at 10-' 1'v1, 1IJ'M and 11J7 ivi significantly decreased the
radicle length as call/pared 10 the confrol.
The investigation on the potential of Ihe species for growing on degraded land involved the growing of seedlings
(GA, 10-' }v1 h'eated and Ihe conh'ol) in plastic bags in Ihe greenhouse. Soil samples ji'Oln degraded land were
collecled ji'om geomorphicolly different locations ji'om an area co 4 km' along Ihe road on Ihe l'vfodjo-Zeway
road, at aboul 81 km soulh of Addis Ababa. Soil samples that served as a control were collected ji'01l/ places in
and orollnd Addis Ababa where A. abyssinica is currently found growing. Gel1ninants ji'om 10-' JIIi GA, and the
conh'ol were plan led in bolh types of soils and were left 10 grow in Ihe greenhouse fOI' 12 weeks. All the seedlings
slllvived until ha/vest. Chemical and physical analyses of the soil samples were conducled in Ihe National Soils
Laborato/y in Addis Ababa. The results of the analyses indicate that 10talnih'Ogen, organic carbon and available
phosphorus were Significantly higher (p < O. 05) in the soils collecled ji'om places where A. abyssinica is cun'enlly
grolVing than those ji'om Ihe deg/'Qded land On fhe other hand pH, No, K, Co, and CEC were found Significantly higher (p ~ 0.00) ill the soils collectedjimll degraded land The JIIeall vollies of plant height. IIIlmber ofbrallches.
IIl1l1/ber of leaves. shoot dry weight alld root dry weight were fOlllld to be sigllificalltly higher ill the controls. FroJII
the resllits. it cOllld be cOllelllded that: (I) the presellce of hard seed coats is the most ill/portallt factor inhibitillg
gel7nillalioll ill seeds of A. abyssillica; (2) provided that seeds are carejilily scarified (chemically or
mechanically), no gennination stimulators are required for obtaining maximum percentage germination; and (3)
the slllvival (IIntii hmvesl) of the seedlillgs ill soils collected ji'om degraded lalld cOllld illdicate that A. abyssillica
has the potelllials for growillg ill degraded land provided that the minimllm moistllre reqllirements of the species
is met.
Description
Keywords
Biology