Premium
Some Effects of Leaf Area, Solar Radiation, Air Temperature, and Variety on Net Photosynthesis in Field‐Grown Soybeans 1
Author(s) -
Jeffers D. L.,
Shibles R. M.
Publication year - 1969
Publication title -
crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.76
H-Index - 147
eISSN - 1435-0653
pISSN - 0011-183X
DOI - 10.2135/cropsci1969.0011183x000900060027x
Subject(s) - leaf area index , photosynthesis , biology , radiation , air temperature , photosynthetically active radiation , botany , horticulture , atmospheric sciences , physics , quantum mechanics
The effect of leaf area index, solar radiation, and air temperature on photosynthesis (net CO 2 assimilation) leaf canopies of three soybean ( Glycine max L., Merr.) varieties was studied. Sections of field plots (1.16‐m 2 ) were enclosed in transparent chambers, and CO 2 assimilation rates were determined by infrared gas analysis. From a maximum of about 60 mg CO 2 2/dm 2 (ground area) .hr on July 5, the assimilation rate declined to 53 mg CO 2 /dm 2 .hr by Sept. 9. Maximum variety differences were 8 mg CO 2 /dm 2 .hr. An interaction occurred between LAI and solar radiation in their effect of photosynthesis; the critic:d LAI was 5 to 6 at 0.2 ly/min solar radiation and greater than 8 (maximum LAI attained) at 1.2 ly/min. Below LAI of four canopies showed light saturation. Optimum air temperature was 25–30 C.