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Seasonal Changes in the Photosynthetic Capacity of Winter Rape Plants under Different Nitrogen Regimes Measured in the Field
Author(s) -
Kappen L.,
Hammler A.,
Schultz G.
Publication year - 1998
Publication title -
journal of agronomy and crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.095
H-Index - 74
eISSN - 1439-037X
pISSN - 0931-2250
DOI - 10.1111/j.1439-037x.1998.tb00415.x
Subject(s) - photosynthesis , nitrogen , agronomy , productivity , photosynthetic capacity , respiration , growing season , leaf area index , field experiment , biology , horticulture , botany , environmental science , chemistry , organic chemistry , economics , macroeconomics
Winter rape (cv.‘Falcon’) grown under different nitrogen regimes (N 0 , N 120 ; 0 and 120 kg.ha −1 , respectively) in northern Germany was investigated over the 1996 spring–summer season. Using a CO 2 , H 2 O diffusion porometer, diurnal courses or net photosynthesis and respiration were measured in situ and were related to microclimatic conditions and leaf water relations. Photosynthesis was modelled and daily CO 2 gain was calculated. In contrast to the N 120 plants, plants of the low nitrogen plot (N 0 ) grew less densely and their leaves behaved more like sun leaves. Increased nitrogen supply had little influence on photosynthetic capacity but it increased productivity through higher leaf area index and an extended period of photosynthetic activity. N 120 plants also appeared to be better acclimated to hot, summer conditions. Higher nitrogen supply substantially increased seed production with the yield of the N 120 plants being 16% of the N 0 plants.