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Increased growth of young citrus trees under reduced radiation load in a semi-arid climate
Year:
2003
Source of publication :
Journal of Experimental Botany
Authors :
Cohen, Shabtai
;
.
Grava, Avraham
;
.
Raveh, Eran
;
.
Volume :
54
Co-Authors:
Raveh, E., Institute of Horticulture, ARO Volcani Center, POB 6, Bet Dagan 50250, Israel
Cohen, S., Dept. of Environ. Phys./Irrigation, Inst. of Soil, Water/Environ. Sci., ARO Volcani Center, POB 6, Bet Dagan 50250, Israel
Raz, T., Inst. of Plant Sci./Genet. in Agric., Hebrew University of Jerusalem, Rehovot 76100, Israel
Yakir, D., Department of Environmental Sciences, Weizmann Inst. of Science, Rehovot 76100, Israel
Grava, A., Dept. of Environ. Phys./Irrigation, Inst. of Soil, Water/Environ. Sci., ARO Volcani Center, POB 6, Bet Dagan 50250, Israel
Goldschmidt, E.E., Inst. of Plant Sci./Genet. in Agric., Hebrew University of Jerusalem, Rehovot 76100, Israel
Facilitators :
From page:
365
To page:
373
(
Total pages:
9
)
Abstract:
This study investigated the effects of radiation heat-load reduction by shading on the growth and development of citrus trees in a warm subtropical region. The experiment was conducted from mid-June until late October when daily maximal air temperature averaged 29.3°C. Two-year-old de-fruited Murcott tangor (Citrus reticulata Blanco x Citrus sinensis (L.) Osb.) trees were grown under 30% or 60% shade tunnels, or 60% flat shade (providing midday shade only), using highly reflective aluminized nets. Non-shaded trees were used as the control. Shading reduced direct more than diffuse radiation. Daily radiation was reduced by 35% for the 30% Tunnel and 60% Flat treatments, and by 55% for the 60% Tunnel. Two days of intensive measurement showed that shading increased average sunlit leaf conductance by 44% and photosynthesis by 29%. Shading did not significantly influence root and stem dry weight growth, but it increased the increment in leaf dry weight during the three month period by an average of 28% relative to the control, while final tree height in the 30% Tunnel treatment exceeded the control by 35%. Shoot to root and shoot mass ratios increased and root mass ratio decreased due to shading because of the increase in leaf dry weight. Shading increased starch concentration in leaves while the shadiest treatment, 60% Tunnel, decreased starch concentration in the roots. Carbon isotope ratio (δ13C) of exposed leaves that developed under shading was significantly reduced by 1.9‰ in the 60% Tunnel, indicating that shading increased CO2 concentrations at the chloroplasts (Cc), as would be expected from increased conductance. Substomatal CO2 concentrations, Ci, computed from leaf net CO2 assimilation rate and conductance values, also indicate that shading increases internal CO2 concentrations. Based on tree dry mass, tree height, and total carbohydrates fractions, the 30% Tunnel and the 60% Flat were the optimal shade treatments.
Note:
Related Files :
carbohydrates
climatology
Growth, Development and Aging
Leaf conductance
partitioning
photosynthesis
shade
tree
trees
Show More
Related Content
More details
DOI :
10.1093/jxb/54.381.365
Article number:
0
Affiliations:
Database:
Scopus
Publication Type:
article
;
.
Language:
English
Editors' remarks:
ID:
30995
Last updated date:
02/03/2022 17:27
Creation date:
17/04/2018 00:58
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Scientific Publication
Increased growth of young citrus trees under reduced radiation load in a semi-arid climate
54
Raveh, E., Institute of Horticulture, ARO Volcani Center, POB 6, Bet Dagan 50250, Israel
Cohen, S., Dept. of Environ. Phys./Irrigation, Inst. of Soil, Water/Environ. Sci., ARO Volcani Center, POB 6, Bet Dagan 50250, Israel
Raz, T., Inst. of Plant Sci./Genet. in Agric., Hebrew University of Jerusalem, Rehovot 76100, Israel
Yakir, D., Department of Environmental Sciences, Weizmann Inst. of Science, Rehovot 76100, Israel
Grava, A., Dept. of Environ. Phys./Irrigation, Inst. of Soil, Water/Environ. Sci., ARO Volcani Center, POB 6, Bet Dagan 50250, Israel
Goldschmidt, E.E., Inst. of Plant Sci./Genet. in Agric., Hebrew University of Jerusalem, Rehovot 76100, Israel
Increased growth of young citrus trees under reduced radiation load in a semi-arid climate
This study investigated the effects of radiation heat-load reduction by shading on the growth and development of citrus trees in a warm subtropical region. The experiment was conducted from mid-June until late October when daily maximal air temperature averaged 29.3°C. Two-year-old de-fruited Murcott tangor (Citrus reticulata Blanco x Citrus sinensis (L.) Osb.) trees were grown under 30% or 60% shade tunnels, or 60% flat shade (providing midday shade only), using highly reflective aluminized nets. Non-shaded trees were used as the control. Shading reduced direct more than diffuse radiation. Daily radiation was reduced by 35% for the 30% Tunnel and 60% Flat treatments, and by 55% for the 60% Tunnel. Two days of intensive measurement showed that shading increased average sunlit leaf conductance by 44% and photosynthesis by 29%. Shading did not significantly influence root and stem dry weight growth, but it increased the increment in leaf dry weight during the three month period by an average of 28% relative to the control, while final tree height in the 30% Tunnel treatment exceeded the control by 35%. Shoot to root and shoot mass ratios increased and root mass ratio decreased due to shading because of the increase in leaf dry weight. Shading increased starch concentration in leaves while the shadiest treatment, 60% Tunnel, decreased starch concentration in the roots. Carbon isotope ratio (δ13C) of exposed leaves that developed under shading was significantly reduced by 1.9‰ in the 60% Tunnel, indicating that shading increased CO2 concentrations at the chloroplasts (Cc), as would be expected from increased conductance. Substomatal CO2 concentrations, Ci, computed from leaf net CO2 assimilation rate and conductance values, also indicate that shading increases internal CO2 concentrations. Based on tree dry mass, tree height, and total carbohydrates fractions, the 30% Tunnel and the 60% Flat were the optimal shade treatments.
Scientific Publication
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