Optimising Lai in Bent Rose Shoots

Pien, Helga; Bobelyn, Els; Lemeur, Raoul; Labeke, Marie-Christine Van

doi:10.17660/actahortic.2001.547.38

Cited by 13 publications

(9 citation statements)

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“…LAI between 1 and 3.5 is recommended for optimizing the photosynthetic area in the bent shoot system (Pien et al, 2001). We validated the models with our measured data, and verifi ed the lack of fi t between NDVI and LAI in the higher values; therefore we assumed that SRI was more reliable in our experiment.…”

Section: Resultssupporting

confidence: 57%

Leaf Area Index, Water Index, and Red: Far Red Ratio Calculated by Spectral Reflectance and its Relation to Plant Architecture and Cut Rose Production

Mascarini¹,

Lorenzo²,

Vilella³

2006

jashs

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In roses (Rosa ×hybrida L.), the bending of branches is a technique that modifies the canopy of the plant and could affect such parameters as the leaf area index (LAI), the quality of reflected light, and the water index (WI) of the plant. The measurement of spectral reflectance with remote sensors is a nondestructive, quick, and simple method to study these parameters. The aim of this paper is to quantify the modification of reflected radiation quality, the LAI and the water index of the plant with different canopies, and its impact on flowering and the number and quality of flowers produced. In R. ×hybrida `Terracotta', using the spectral crop reflectance, the red: far red ratio [red (R) = 680 nm; far red (FR) = 730 nm], percentage of blue light of reflected radiation, and vegetation indices [normalized difference vegetation index (NDVI), simple ratio index (SRI), water index (WI)] were calculated in two architectural managements: traditional (upright hedge) and bent shoot. NDVI had a greater correlation with LAI than SRI (r2 = 0.98 and 0.85, respectively), but SRI was more reliable for LAI values of 1 to 3.5. The bent shoot system compared to the traditional one decreased the R:FR ratio of reflected radiation and increased LAI and plant water content. These changes were related to a higher commercial quality of the flowers (longer flowering shoots with a larger stem diameter and fresh weight), although there was no significant difference in the number of flowers harvested. The period that showed the largest difference in the quality of the flower using the bent shoot system had a LAI of 2.8 vs. 1.8 with traditional management and a marked reduction in the R:FR of the light reflected by bent plants. The bent shoot system advanced the peak production by 1 month at the end of winter and improved the flowers at a time when sun radiation is limiting factor for production.

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Section: Resultssupporting

confidence: 57%

Leaf Area Index, Water Index, and Red: Far Red Ratio Calculated by Spectral Reflectance and its Relation to Plant Architecture and Cut Rose Production

Mascarini¹,

Lorenzo²,

Vilella³

2006

jashs

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“…simulation results, discussed that the contribution of bent shoots to whole-canopy would depend on the light availability to the bent shoots and the density of bent and erect shoots of a canopy. Under low light conditions, maintaining many bent shoots in the canopy could be detrimental to whole-canopy assimilation (Kim and Lieth, 2002;Pien et al, 2001). At a single-leaf scale, the negative effect of bending on A was most pronounced at light saturated conditions (Fig.…”

Section: Discussionmentioning

confidence: 99%

Bending Alters Water Balance and Reduces Photosynthesis of Rose Shoots

Kim¹,

Shackel²,

Lieth³

2004

jashs

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Shoot-bending has become a standard cultural practice in cut-flower rose (Rosa hybrida L.) production. Physiological effects of shoot-bending on leaf net photosynthesis (A), stomatal conductance (gs), transpiration rate (E), and stem water potential (ψ) were investigated for rose plants. With saturating light conditions, shoot-bending decreased rates of A, gs, and E in comparison with the rates prior to shoot-bending. A, gs, and E of bent shoots were significantly lower than those of the control shoots that were not bent. The differences in A between bent and control shoots decreased over time, disappearing within 3 weeks after bending. Bent shoots exhibited reduced ψ. Leaves projecting upward on a bent stem were found to have higher A, gs, and E than those projecting downward. This was probably due to the destruction of xylem vessels serving the leaves attached to the lower side (compression side) of the bent stem. Our results support the hypothesis that hydraulic conductivity is reduced in bent shoots probably due to disturbed xylem tissues, and that reduced photosynthetic rates of bent shoots are a function of water status.

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“…Increasing leaf area does not enhance canopy assimilation rate unlimitedly due to leaves mutual shading caused by clumping effect. Lower layer of the bent shoots contributes negatively to the total canopy carbohydrate balance if its leaf area exceeds an optimal range (Pien et al, 2001). As a consequence, before adopting any type of training system or pruning strategy one should consider the results of in situ researches and try to optimize the canopy architecture and morphology based on environmental conditions and plant physiological and phonological characteristics.…”

Section: Training Systems and Canopy Photosynthesismentioning

confidence: 99%

Light Harvesting and Photosynthesis by the Canopy

Matloobi¹

2012

Advances in Photosynthesis - Fundamental Aspects

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Optimising Lai in Bent Rose Shoots

Cited by 13 publications

References 0 publications

Leaf Area Index, Water Index, and Red: Far Red Ratio Calculated by Spectral Reflectance and its Relation to Plant Architecture and Cut Rose Production

Leaf Area Index, Water Index, and Red: Far Red Ratio Calculated by Spectral Reflectance and its Relation to Plant Architecture and Cut Rose Production

Bending Alters Water Balance and Reduces Photosynthesis of Rose Shoots

Light Harvesting and Photosynthesis by the Canopy

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