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Adaptive Implications of Leaf Thickness for Sun‐ and Shade‐Grown Abutilon Theophrasti
Author(s) -
Yun Jin Il,
Taylor S. Elwynn
Publication year - 1986
Publication title -
ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.144
H-Index - 294
eISSN - 1939-9170
pISSN - 0012-9658
DOI - 10.2307/1938687
Subject(s) - transpiration , abutilon , photosynthesis , photosynthetically active radiation , botany , seedling , biology , horticulture , irradiance , shading , physics , quantum mechanics , weed , art , visual arts
Potentially adaptive effects of leaf thickness on photosynthesis and transpiration were studied for Abutilon theophrasti grown under high (600 μmol°m — 2 °s — 1 ) and low (200 μmol°m — 2 °s — 1 ) levels of photosynthetically active radiation. We determined the relationship of both surface area and volume of mesophyll cells of leaf thickness. Net photosynthesis and transpiration rates were measured on the third leaf of each seedling, under sunny (1200 μmol°m — 2 °s — 1 ) and shaded (250 μmol°m — 2 °s — 1 ) conditions. Plants grown under high light had greater mesophyll surface area and total mesophyll cell volume per unit leaf area than did plants grown under low light, and showed higher net photosynthesis under sunny conditions. There was little difference in transpiration rate between thick and thin leaves. Thick leaves and thin leaves showed similar net photosynthesis under shaded conditions. Consequently, the water use efficiency for thick leaves was greater than that for thin leaves under sunny conditions. Increased productivity without increased water use is potentially of adaptive significance in plants where the mesophyll of sun—grown leaves thickens.