Photosynthetically versatile thin shade leaves: A paradox of irradiance-response curves |
| |
Authors: | M Tateno H Taneda |
| |
Institution: | (1) Nikko Botanical Garden, Graduate School of Science, University of Tokyo, Nikko, Tochigi 321-1435, Japan |
| |
Abstract: | Thick sun leaves have a larger construction cost per unit leaf area than thin shade leaves. To re-evaluate the adaptive roles
of sun and shade leaves, we compared the photosynthetic benefits relative to the construction cost of the leaves. We drew
photosynthetically active radiation (PAR)-response curves using the leaf-mass-based photosynthetic rate to reflect the cost.
The dark respiration rates of the sun and shade leaves of mulberry (Morus bombycis Koidzumi) seedlings did not differ significantly. At irradiances below 250 μmol m−2 s−1, the shade leaves tended to have a significantly larger net photosynthetic rate (P
N) than the sun leaves. At irradiances above 250 μmol m−2 s−1, the P
N did not differ significantly. The curves indicate that plants with thin shade leaves have a larger daily CO2 assimilation rate per construction cost than those with thick sun leaves, even in an open habitat. These results are consistently
explained by a simple model of PAR extinction in a leaf. We must target factors other than the effective assimilation when
we consider the adaptive roles of thick sun leaves. |
| |
Keywords: | construction cost dark respiration rate mesophyll Morus mulberry net photosynthetic rate photosynthetically active radiation |
本文献已被 SpringerLink 等数据库收录! |
|