Light quality (red:far-red ratio): does it affect photosynthetic activity, net CO2assimilation, and morphology of young white clover leaves?
作者:
V Heraut-Bron,
C Robin,
C Varlet-Grancher,
D Afif,
A Guckert,
期刊:
Canadian Journal of Botany
(NRC Available online 2000)
卷期:
Volume 77,
issue 10
页码: 1425-1431
ISSN:0008-4026
年代: 2000
DOI:10.1139/b99-099
出版商: NRC Research Press
数据来源: NRC
摘要:
We assessed the effects of red:far-red (R:FR) ratio on net CO2assimilation, photosynthetic activity, and morphology of young white clover leaves developed under a simulated canopy light environment. Isolated cuttings ofTrifolium repensL. were grown in controlled conditions under two irradiances in combination with two R:FR ratios. We used far-red light emitting diodes to reduce the R:FR ratio on leaves that were successively developing on the main stolon and were subject to strong competition for light within a sward. A leaf that developed under a low R:FR ratio had a lower chlorophyll content than the controls. However, this change had no consequences on the net CO2assimilation rate and on the biomass allocated to shoots. The low R:FR ratio modified the leaf morphology by increasing the leaf area. A leaf that developed in lower irradiance had a lower net CO2assimilation rate and a greater leaf area and petiole length than leaves that developed in higher irradiance. Therefore, irradiance was the main factor limiting the leaf CO2assimilation under a canopy. Capture of light by clover leaves was improved by FR light only via modifications of leaf morphology, because there were no significant effects of FR light on photosynthesis.
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