Abstract
Three‐month‐old sugarcane ( Saccharum officinarum ) plants were raised from single‐eye cuttings and grown in aerated nutrient solution for an additional 28 days at an air temperature fluctuating between 21.5 C (night) and 30.5 C (day). The nutrient solutions in which the roots were immersed were kept at eight different temperatures ranging from 12.5 C to 33.5 C. Half the number of plants in each temperature treatment were treated weekly with gibberellic acid (GA). The GA (100 µg) was applied in 0.1 ml of water per plant in the folded leaves above the top visible dewlap. A loss in mean dry weight of the plants at a root temperature of 12.5 C indicated a higher respiratory than photosynthetic activity. Above 15.5 C an increase in root temperature resulted in an almost linear increase in dry matter production up to 30.5 C. The effect of GA on dry matter production was more pronounced at 18.5 C than at 27.5 C to 30.5 C. There was very little response to GA application at intermediate temperatures. Tiller production was reduced by root temperature below 24.5 C, above which there was an increase in the mean number and mean dry weight of tillers with increasing temperature. GA caused a reduction in tiller dry weight at 27.5 C; however, the effect decreased above that temperature. It is suggested that GA production in the roots, or translocation from the roots, or both, are inhibited by root temperatures below 18.5 C, which would explain the high response to applied GA at 18.5 C. At temperatures of 27.5 C and 30.5 C a positive response to exogenous GA might be the result of depletion, through consumption of endogenous GA due to the rapid growth rate of the plants at these temperatures. The growth of the GA‐treated plants was maximum at a root temperature of 30.5 C under the conditions of the experiment. for the control plants maximum growth was attained at the root temperature of 33.5 C. However, the maximum response to GA, compared to the controls at the same temperature, occured at 18.5 C.
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Claims 11
Claim · model-written summary
At 12.5 C root temperature, plant mean dry weight declined.
Not reportedComparator
Verbatim
e0“A loss in mean dry weight of the plants at a root temperature of 12.5 C”
t0“sugarcane”
t1“sugarcane”
Claim · model-written summary
Above 15.5 C, increasing root temperature raised dry matter production almost linearly to 30.5 C.
Verbatim
e0“Above 15.5 C an increase in root temperature resulted in an almost linear increase in dry matter production up to 30.5 C.”
t0“sugarcane”
t1“sugarcane”
Claim · model-written summary
GA affected dry matter production more at 18.5 C than 27.5 to 30.5 C.
Verbatim
e0“The effect of GA on dry matter production was more pronounced at 18.5 C than at 27.5 C to 30.5 C.”
t0“sugarcane”
t1“sugarcane”
Claim · model-written summary
GA application produced very little response at intermediate temperatures.
- Taxon
- sugarcanet0
- Treatment
- GA applicatione0
- Outcome
- very little responsee0
- Qualifier
- intermediate temperaturese0
Not reportedComparatorDirection
Verbatim
e0“There was very little response to GA application at intermediate temperatures.”
t0“sugarcane”
t1“sugarcane”
Claim · model-written summary
Root temperatures below 24.5 C reduced tiller production.
- Taxon
- sugarcanet0
- Treatment
- root temperature below 24.5 Ce0
- Outcome
- Tiller productione0
- Direction
- reducede0
Not reportedComparator
Verbatim
e0“Tiller production was reduced by root temperature below 24.5 C”
t0“sugarcane”
t1“sugarcane”
Claim · model-written summary
Above 24.5 C, increasing temperature raised tiller number and dry weight.
Verbatim
e0“above which there was an increase in the mean number and mean dry weight of tillers with increasing temperature.”
t0“sugarcane”
t1“sugarcane”
Claim · model-written summary
GA reduced tiller dry weight at 27.5 C.
Not reportedComparator
Verbatim
e0“GA caused a reduction in tiller dry weight at 27.5 C”
t0“sugarcane”
t1“sugarcane”
Claim · model-written summary
The GA effect on tiller dry weight diminished above 27.5 C.
Verbatim
e0“however, the effect decreased above that temperature.”
t0“sugarcane”
t1“sugarcane”
Claim · model-written summary
GA treated plants grew most at 30.5 C root temperature.
Verbatim
e0“The growth of the GA‐treated plants was maximum at a root temperature of 30.5 C under the conditions of the experiment.”
t0“sugarcane”
t1“sugarcane”
Claim · model-written summary
Control plants attained maximum growth at 33.5 C root temperature.
Verbatim
e0“for the control plants maximum growth was attained at the root temperature of 33.5 C.”
t0“sugarcane”
t1“sugarcane”
Claim · model-written summary
The maximum GA response relative to controls occurred at 18.5 C.
Verbatim
e0“the maximum response to GA, compared to the controls at the same temperature, occured at 18.5 C.”
t0“sugarcane”
t1“sugarcane”
The same questions in other papers
Gibberellic acid · yield · Saccharum officinarum (sugarcane)Positive and negative results
9 papers in the same direction as this paper · 1 in the opposite direction
- no effect
- positive
- positive
7 papers more in this group
See all 11 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.