Abstract
Leaf area development is an important determinant of the proportion of the incident radiation intercepted and consequently of stem yield for paper pulp production in kenaf (Hibiscus cannabinus L.). Relationships were developed describing the component processes of node production, leaf area per node and leaf area senescence, to predict green leaf area of non-branching plants of kenaf during the period from sowing to flowering. Data were collected on cultivar Guatemala 4 grown under irrigation at a range of plant population densities at three sites in tropical Australia. The thermal time required for production of new nodes remained constant from sowing to flowering at 36.3¦C days node-' at a population of 50 plants m-2. Leaf area per node was described quantitatively in terms of three phases where, as node number increased, leaf area per node at first increased linearly, reached a plateau and finally declined linearly. The rate at which the leaf area at old nodes was senesced was found to be equivalent to the rate of production of new nodes, such that the number of nodes bearing green leaves was relatively constant; at a population of 50 plants m-2 there was green leaf area at 7 nodes plant-1 over time. Empirical functions describing the effects of plant population on rates of node production and senescence and on maximum leaf area per node were developed. In limited testing, these functions predicted leaf area development of crops of kenaf grown under optimal conditions. The functions developed here, when combined with others in this series of papers, provide algorithms to be used in the development of a crop simulation model of kenaf for use in the semi-arid tropics of northern Australia.
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Claims 6
Claim · model-written summary
At 50 plants m-2, thermal time per new node remained constant at 36.3¦C days node-1 from sowing to flowering.
- Taxon
- kenaf
Hibiscus cannabinust0 - Outcome
- thermal time required for production of new nodese0
- Direction
- remained constante0
- Value
- 36.3¦C days node-'e0
- Qualifier
- 50 plants m-2e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“kenaf”
e0“The thermal time required for production of new nodes remained constant from sowing to flowering at 36.3¦C days node-' at a population of 50 plants m-2.”
Claim · model-written summary
Leaf area per node increased linearly, plateaued, then declined linearly with node number.
- Taxon
- kenafHibiscus cannabinust0
- Outcome
- leaf area per nodee0
- Direction
- increased linearly, reached a plateau and finally declined linearlye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“kenaf”
e0“as node number increased, leaf area per node at first increased linearly, reached a plateau and finally declined linearly”
Claim · model-written summary
Old-node leaf senescence matched production of new nodes.
- Taxon
- kenafHibiscus cannabinust0
- Organ / stage
- old nodese0
- Outcome
- rate at which the leaf area at old nodes was senescede0
- Direction
- equivalente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“kenaf”
e0“The rate at which the leaf area at old nodes was senesced was found to be equivalent to the rate of production of new nodes”
Claim · model-written summary
At 50 plants m-2, green leaves occupied seven nodes per plant over time.
- Taxon
- kenafHibiscus cannabinust0
- Outcome
- green leaf areae0
- Value
- 7 nodes plant-1e0
- Qualifier
- 50 plants m-2e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“kenaf”
e0“at a population of 50 plants m-2 there was green leaf area at 7 nodes plant-1 over time”
Claim · model-written summary
Empirical functions described effects of plant population on node production, senescence and maximum leaf area per node.
- Taxon
- kenafHibiscus cannabinust0
- Outcome
- rates of node production and senescence and on maximum leaf area per nodee0
- Comparator
- plant populatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“kenaf”
e0“Empirical functions describing the effects of plant population on rates of node production and senescence and on maximum leaf area per node were developed.”
Claim · model-written summary
In limited testing, the functions predicted leaf area development under optimal crop conditions.
- Taxon
- kenafHibiscus cannabinuse0
- Outcome
- leaf area developmente0
- Qualifier
- under optimal conditionse0
Not reportedComparatorValue
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In limited testing, these functions predicted leaf area development of crops of kenaf grown under optimal conditions.”