Articles
The non-leaf tissues at the top of dwarf tomato canopy inhibit its photosynthesis
Article number
1423_3
Pages
17 – 24
Language
English
Abstract
Dwarf tomatoes offer numerous advantages when cultivated in a plant factory with artificial light (PFAL), also known as a vertical farm.
In PFALs, downward lighting emitted from lamps above the plants is usually used for illumination, and most of the light is absorbed by the topmost canopy.
At the reproductive stage, the proportion of projected non-leaf tissue area to the projected total plant area from the top canopy can increase to 31.5% in ‘Micro-Tom’, a famous dwarf and determinate tomato cultivar.
However, it is unclear whether the photosynthetic rate of non-leaf tissues is as high as that of leaves in dwarf tomatoes under the same lighting conditions.
An open-type assimilation chamber was used to measure the photosynthetic rates of the whole plant and non-leaf tissues using 63-day-old plants.
The leaf photosynthetic rate was measured by a LI-6400XT portable photosynthesis system.
Additionally, the proportion of CO2 fixation by non-leaf tissues to that by the whole canopy was calculated.
The results evidently demonstrated that the photosynthetic rate of the non-leaf tissues was 20% of the leaf photosynthetic rate.
In addition, the canopy photosynthetic rate was lower than the leaf photosynthetic rate but higher than the photosynthetic rate of the non-leaf tissues.
The CO2 fixation by non-leaf tissues was 9.2% by the whole canopy.
In conclusion, the non-leaf tissues at the top of the canopy inhibit the photosynthesis of the canopy and further reduce radiation-use efficiency at the reproductive growth stage.
Change in light direction may improve radiation-use efficiency and photosynthetic rate of the canopy and reduce light consumption by the non-leaf tissues.
In PFALs, downward lighting emitted from lamps above the plants is usually used for illumination, and most of the light is absorbed by the topmost canopy.
At the reproductive stage, the proportion of projected non-leaf tissue area to the projected total plant area from the top canopy can increase to 31.5% in ‘Micro-Tom’, a famous dwarf and determinate tomato cultivar.
However, it is unclear whether the photosynthetic rate of non-leaf tissues is as high as that of leaves in dwarf tomatoes under the same lighting conditions.
An open-type assimilation chamber was used to measure the photosynthetic rates of the whole plant and non-leaf tissues using 63-day-old plants.
The leaf photosynthetic rate was measured by a LI-6400XT portable photosynthesis system.
Additionally, the proportion of CO2 fixation by non-leaf tissues to that by the whole canopy was calculated.
The results evidently demonstrated that the photosynthetic rate of the non-leaf tissues was 20% of the leaf photosynthetic rate.
In addition, the canopy photosynthetic rate was lower than the leaf photosynthetic rate but higher than the photosynthetic rate of the non-leaf tissues.
The CO2 fixation by non-leaf tissues was 9.2% by the whole canopy.
In conclusion, the non-leaf tissues at the top of the canopy inhibit the photosynthesis of the canopy and further reduce radiation-use efficiency at the reproductive growth stage.
Change in light direction may improve radiation-use efficiency and photosynthetic rate of the canopy and reduce light consumption by the non-leaf tissues.
Authors
X. Ke, K. Saito, H. Yoshida, S. Hikosaka, E. Goto
Keywords
‘Micro-Tom’, open-type assimilation chamber, photosynthetic rate, PFAL
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