Cotton leaf photosynthesis and age relationship is influenced by leaf position
Photosynthesis rate per unit leaf area and leaf longevity are significant components of field cotton performance. The objective of this study was to determine the relationship between photosynthesis rate and age for leaves located at different positions in canopy. Cotton cultivars 'Sri Sumrong 60' was sowed weekly from June to September 1995 and on May 30, 1996 at Kasetsart University's Suwan experiment station. Net photosynthesis rates at light saturation (Pmax) were measured using open system portable photosynthesis system equipped with LED lamp. The relationship between Pmax and main stem leaf age, without regard to nodal position, was influenced by plant age. Furthermore, relationships between Pmax and leaf age appeared to be similar for main stem leaves on nodes 3- 10. For leaves on nodes 12-15, Pmax declined at slower rate than for nodes 3-15. The main difference of Pmax-age relationships of sympodial and monopodial from main stem leaves seemed to be the proportion of leaves that had Pmax less than the average for main stem leaf at the same leaf age. At specific leaf age, Pmax tended to decline with increase sympodial position. In addition, Pmax of monopodial leaves had very large variation, and were less responsive to leaf age than for main stem leaves. Analysis of Pinax-node position for specific age revealed that for main stem leaves at lower node Pmax peaked earlier and longevity was shorter than leaves at higher modes. Differences in Pmax-age relationships for leaves at various main stem, sympodia, and monopodial position were thought to result from leaf acclimation to limiting available PPF resources.
| Main Authors: | , , |
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| Format: | article biblioteca |
| Language: | eng |
| Subjects: | F61 - Physiologie végétale - Nutrition, Gossypium, feuille, photosynthèse, âge, stade de développement végétal, couvert, http://aims.fao.org/aos/agrovoc/c_3335, http://aims.fao.org/aos/agrovoc/c_4243, http://aims.fao.org/aos/agrovoc/c_5812, http://aims.fao.org/aos/agrovoc/c_186, http://aims.fao.org/aos/agrovoc/c_5959, http://aims.fao.org/aos/agrovoc/c_1262, |
| Online Access: | http://agritrop.cirad.fr/6570/ |
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