Abstract
Phytochrome-regulated stem and petiole elongation is of great horticultural importance due to their effects on height and compactness of plants. Although it is believed that phytochrome action during cell elongation is controlled via gibberellin (GA) biosynthesis, conclusive evidence has not been presented. In this study, watermelon plants pre-treated with GAs or GA biosynthesis inhibitors were briefly exposed to red (R) or far-red (FR) at the end of photoperiod to investigate the involvement of GAs in phytochrome-regulated stem and petiole elongation. Two-week-old watermelon plants were applied with either GAs, GA 3 (25 ppm) or GA 4+7 (25 ppm), or GA biosynthesis inhibitors, paclobutrazol (early stage inhibitor, 2 ppm) or prohexadione-Ca (late stage inhibitor, 200 ppm). Following chemical application, plants were treated with low-intensity R or FR light for 15 min at the end of photoperiod for 8 days. The increased petiole length and increased dry mass partitioned to petioles caused by FR were further increased when plants were pre-treated with GA 3 and GA 4+7 , but reduced when plants were pre-treated with paclobutrazol or prohexadione-Ca. Pre-treatment with paclobutrazol or prohexadione-Ca further reduced the petiole length and dry mass partitioned to petioles caused by R alone, but effects of R were reversed when plants were pre-treated with GA 3 and GA 4+7 . Petiole growth changes were significant after 2 to 3 days of treatments and there was no light or growth regulator effects on stem growth. Low leaf chlorophyll content and higher photosynthesis resulted in FR-treated plants were not observed when plants were pre-treated with paclobutrazol or prohexadione-Ca. Prohexadione-Ca was more effective in reversing FR induced petiole elongation than paclobutrazol, while GA 4+7 was more effective than GA 3 in promoting the effects of FR and reversing the effects of R. These results provide further evidence that phytochrome regulated growth changes in watermelon are due to the changes in GA biosynthesis. It is also suggestive that phytochrome has differential regulation of GA biosynthesis.
Abstract from the paper’s OpenAlex record, shown for indexing and research. Copyright remains with the authors or the publisher. Read at the source ↗
The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.
Claims 12
Claim · model-written summary
Gibberellin pretreatment further increased far red induced petiole length and dry mass partitioning.
- Taxon
- Watermelon
Citrullus lanatust0 - Treatment
- GA 3 and GA 4+7e0
- Outcome
- petiole length and increased dry mass partitioned to petiolese0
- Direction
- further increasede0
- Comparator
- FRe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The increased petiole length and increased dry mass partitioned to petioles caused by FR were further increased when plants were pre-treated with GA 3 and GA 4+7”
t0“Watermelon”
Claim · model-written summary
Inhibitor pretreatment reduced the far red petiole response.
- Taxon
- WatermelonCitrullus lanatust0
- Treatment
- paclobutrazol or prohexadione-Cae0
- Outcome
- reducede0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“but reduced when plants were pre-treated with paclobutrazol or prohexadione-Ca.”
t0“Watermelon”
Claim · model-written summary
Inhibitors further reduced red light petiole length and dry mass partitioning.
- Taxon
- WatermelonCitrullus lanatust0
- Treatment
- paclobutrazol or prohexadione-Cae0
- Outcome
- petiole length and dry mass partitioned to petiolese0
- Direction
- further reducede0
- Comparator
- R alonee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Pre-treatment with paclobutrazol or prohexadione-Ca further reduced the petiole length and dry mass partitioned to petioles caused by R alone”
t0“Watermelon”
Claim · model-written summary
Gibberellins reversed red light effects.
- Taxon
- WatermelonCitrullus lanatust0
- Treatment
- GA 3 and GA 4+7e0
- Outcome
- effects of Re0
- Direction
- reversede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“effects of R were reversed when plants were pre-treated with GA 3 and GA 4+7”
t0“Watermelon”
Claim · model-written summary
Petiole growth changes became significant after 2 to 3 days.
- Taxon
- WatermelonCitrullus lanatust0
- Outcome
- Petiole growth changese0
- Value
- 2 to 3 dayse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Petiole growth changes were significant after 2 to 3 days of treatments”
t0“Watermelon”
Claim · model-written summary
Light and growth regulators had no observed effect on stem growth.
- Taxon
- WatermelonCitrullus lanatust0
- Treatment
- light or growth regulatore0
- Outcome
- stem growthe0
- Direction
- noe0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“there was no light or growth regulator effects on stem growth”
t0“Watermelon”
Claim · model-written summary
Far red plants had low chlorophyll content and higher photosynthesis.
- Taxon
- WatermelonCitrullus lanatust0
- Treatment
- FRe0
- Outcome
- leaf chlorophyll content and higher photosynthesise0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Low leaf chlorophyll content and higher photosynthesis resulted in FR-treated plants”
t0“Watermelon”
Claim · model-written summary
Inhibitors prevented those far red photosynthetic responses.
- Taxon
- WatermelonCitrullus lanatust0
- Treatment
- paclobutrazol or prohexadione-Cae0
- Outcome
- were not observede0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“were not observed when plants were pre-treated with paclobutrazol or prohexadione-Ca”
t0“Watermelon”
Claim · model-written summary
Prohexadione-Ca reversed far red petiole elongation more effectively than paclobutrazol.
- Taxon
- WatermelonCitrullus lanatust0
- Treatment
- Prohexadione-Cae0
- Outcome
- reversing FR induced petiole elongatione0
- Direction
- more effectivee0
- Comparator
- paclobutrazole0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Prohexadione-Ca was more effective in reversing FR induced petiole elongation than paclobutrazol”
t0“Watermelon”
Claim · model-written summary
GA 4+7 was more effective than GA 3 for far red promotion and red effect reversal.
- Taxon
- WatermelonCitrullus lanatust0
- Treatment
- GA 4+7e0
- Outcome
- promoting the effects of FR and reversing the effects of Re0
- Direction
- more effectivee0
- Comparator
- GA 3e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“GA 4+7 was more effective than GA 3 in promoting the effects of FR and reversing the effects of R”
t0“Watermelon”
Claim · model-written summary
Authors attributed watermelon phytochrome growth responses to changed GA biosynthesis.
- Taxon
- WatermelonCitrullus lanatust0
- Outcome
- phytochrome regulated growth changese0
- Qualifier
- changes in GA biosynthesise0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“phytochrome regulated growth changes in watermelon are due to the changes in GA biosynthesis”
t0“Watermelon”
Claim · model-written summary
Phytochrome may differentially regulate GA biosynthesis.
- Taxon
- WatermelonCitrullus lanatust0
- Outcome
- differential regulation of GA biosynthesise0
- Qualifier
- phytochromee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“phytochrome has differential regulation of GA biosynthesis”
t0“Watermelon”
The same questions in other papers
paclobutrazol · growth · Citrullus lanatus (watermelon)Positive and negative results
1 in the opposite direction
- positive
Gibberellic acid · growth · Citrullus lanatus (watermelon)Results agree
7 papers in the same direction as this paper
- positive
- positive
- positive
4 papers more in this group
See all 8 papers →light · growth · Citrullus lanatus (watermelon)Results differ
11 papers in the same direction as this paper · 21 in the opposite direction
- positive
- positive
- positive
29 papers more in this group
See all 33 papers →class · growth · Citrullus lanatus (watermelon)Positive and negative results
2 papers in the same direction as this paper · 7 in the opposite direction
- positive
- positive
- positive
6 papers more in this group
See all 10 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.