Abstract
Abstract The mechanism of ABA‐induced callus formation was studied in sterile bud cultures of Citrus [ Citrus sinensis (L.) Osbeck] on defined media. ABA was found to promote callus formation in the abscission zone between the petiole and the branch while inhibiting bud growth. The promoting effect of ABA was dependent on the physiological state of the shoot from which buds were excised, and on the size of the explant. Callus formation was highest in autumn and summer ( i.e. younger) buds, and lowest in older buds excised from previous summer flush. GA was only slightly active in promoting callus formation when applied separately, but showed a highly synergistic effect when applied with ABA: maximal callus formation was attained at a combination of 10 −5 M ABA and 10 −6 MGA in the medium. Subcultures of ABA‐induced callus revealed that ABA inhibited the growth of isolated subcultured callus, while IAA and kinetin, and especially GA, promoted its rapid proliferation. A general decrease in protein synthesis was found in the abscission zone during the first 5 days of induction, while total protein content changed only slightly. The results suggest that ABA‐induced callus formation in Citrus bud explants is a multiphasic phenomenon involving, at least, two stages: (1) activation of certain cells in the abscission zone by ABA, resulting in the formation of callus layers, and (2) subsequent proliferation of the callus tissue, which is dependent on the hormonal balance in the explant. This growth‐promoting effect of ABA seems to be a general phenomenon in explants exposing a cut‐surface.
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Claims 13
Claim · model-written summary
ABA promoted callus formation in the abscission zone.
CitrusNot reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“ABA was found to promote callus formation in the abscission zone between the petiole and the branch while inhibiting bud growth”
t1“Citrus Bud Cultures”
Claim · model-written summary
ABA inhibited bud growth.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“ABA was found to promote callus formation in the abscission zone between the petiole and the branch while inhibiting bud growth”
t1“Citrus Bud Cultures”
Claim · model-written summary
The callus-promoting effect of ABA depended on shoot physiological state and explant size.
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The promoting effect of ABA was dependent on the physiological state of the shoot from which buds were excised, and on the size of the explant”
t1“Citrus Bud Cultures”
Claim · model-written summary
Callus formation was highest in autumn and younger summer buds and lowest in older buds.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Callus formation was highest in autumn and summer ( i.e. younger) buds, and lowest in older buds excised from previous summer flush”
t1“Citrus Bud Cultures”
Claim · model-written summary
GA alone only slightly promoted callus formation.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“GA was only slightly active in promoting callus formation when applied separately”
t1“Citrus Bud Cultures”
Claim · model-written summary
GA with ABA synergistically promoted callus formation, maximized at the stated combination.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“showed a highly synergistic effect when applied with ABA: maximal callus formation was attained at a combination of 10 −5 M ABA and 10 −6 MGA in the medium”
t1“Citrus Bud Cultures”
Claim · model-written summary
ABA inhibited growth of isolated subcultured callus.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“ABA inhibited the growth of isolated subcultured callus”
t1“Citrus Bud Cultures”
Claim · model-written summary
IAA and kinetin promoted rapid proliferation of isolated callus.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“IAA and kinetin, and especially GA, promoted its rapid proliferation”
t1“Citrus Bud Cultures”
Claim · model-written summary
GA especially promoted rapid proliferation of isolated callus.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“IAA and kinetin, and especially GA, promoted its rapid proliferation”
t1“Citrus Bud Cultures”
Claim · model-written summary
Protein synthesis decreased in the abscission zone during the first five days.
- Organ / stage
- abscission zonee0
- Outcome
- protein synthesise0
- Direction
- decreasee0
- Qualifier
- first 5 days of inductione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A general decrease in protein synthesis was found in the abscission zone during the first 5 days of induction”
t1“Citrus Bud Cultures”
Claim · model-written summary
Total protein content changed only slightly.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“total protein content changed only slightly”
t1“Citrus Bud Cultures”
Claim · model-written summary
The authors propose an ABA-activated callus layer stage followed by hormone-dependent proliferation.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“activation of certain cells in the abscission zone by ABA, resulting in the formation of callus layers, and (2) subsequent proliferation of the callus tissue, which is dependent on the hormonal balance in the explant”
t1“Citrus Bud Cultures”
Claim · model-written summary
ABA growth promotion appears general in explants exposing a cut surface.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“This growth‐promoting effect of ABA seems to be a general phenomenon in explants exposing a cut‐surface”
t1“Citrus Bud Cultures”
The same questions in other papers
Gibberellic acid · growth · CitrusResults differ
6 papers in the same direction as this paper · 2 in the opposite direction
- no effect
- no effect
- positive
5 papers more in this group
See all 9 papers →Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.