What question did this study set out to answer?

To examine how varying crop loads and canopy shading affect foliar carbohydrate concentrations, nitrogen levels, and leaf gas exchange in mature navel orange trees prior to harvest.

September 1, 2003Tree PhysiologyOpen Access

Fruit load and canopy shading affect leaf characteristics and net gas exchange of 'Spring' navel orange trees

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Authors

JSJ. P. SyvertsenNew Mexico State University CGCármen GoñiInstituto Nacional de Investigación Agropecuaria AOAlvaro OteroInstituto Nacional de Investigación Agropecuaria

Discussion

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Implication

Controlled experiment reveals that fruit load and canopy shading alter gas exchange in navel orange trees, indicating sink demand and heat regulate photosynthesis.

Key Points

To examine how varying crop loads and canopy shading affect foliar carbohydrate concentrations, nitrogen levels, and leaf gas exchange in mature navel orange trees prior to harvest.
Subjected 5-year-old 'Spring' navel orange trees to three fruit-load treatments: completely defruited, 50% defruited, or fully laden.
Applied 50% shade cloth over half of the trees across all crop-load treatments for 4 months before winter harvest.
Measured leaf nitrogen, carbohydrate levels, leaf dry mass per area, stomatal conductance, and net CO2 assimilation on clear winter days.
Sunlit leaves on defruited trees showed over 40% lower net CO2 assimilation (Ac) and stomatal conductance (gs), but accumulated higher starch and greater leaf dry mass per area compared to fruited trees.
Under warm conditions where leaf temperature exceeded 25 °C, canopy shading increased Ac and gs without altering the internal-to-ambient CO2 ratio (Ci/Ca), while improving fruit exterior coloration.
Leaves located adjacent to fruit had lower leaf dry mass per area, reduced nitrogen and carbohydrate levels, and lower Ac compared to leaves on non-fruiting branches of the same trees.

Cite This Study

Syvertsen et al. (2003) studied this question.

synapsesocial.com/papers/6a8992e61fe1bad943eb2ddd https://doi.org/10.1093/treephys/23.13.899

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Implication

Controlled experiment reveals that fruit load and canopy shading alter gas exchange in navel orange trees, indicating sink demand and heat regulate photosynthesis.

Fruit load and canopy shading affect leaf characteristics and net gas exchange of 'Spring' navel orange trees

Discussion

Member takes

Implication

Key Points

Cite This Study

Fruit load and canopy shading affect leaf characteristics and net gas exchange of 'Spring' navel orange trees

Discussion

Member takes

Implication

Key Points

Cite This Study

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Also Consider