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Biomass, reproductive output, and physiological responses of rapid‐cycling Brassica ( Brassica rapa ) to ozone and modified root temperature
Author(s) -
KLEIER CATHERINE,
FARNSWORTH BLAKE,
WINNER WILLIAM
Publication year - 1998
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1046/j.1469-8137.1998.00229.x
Subject(s) - brassica rapa , photosynthesis , brassica , biomass (ecology) , shoot , stomatal conductance , biology , dry weight , horticulture , ozone , botany , agronomy , chemistry , organic chemistry
Brassica rapa L. (rapid‐cycling Brassica), was grown in environmentally controlled chambers to determine the interactive effects of ozone (O 3 ) and increased root temperature (RT) on biomass, reproductive output, and photosynthesis. Plants were grown with or without an average treatment of 63 ppb O 3 . RT treatments were 13°C (LRT) and 18°C (HRT). Air temperatures were 25°C/15°C day/night for all RT treatments. Ozone affected plant biomass more than did root temperature. Plants in O 3 had significantly smaller total plant d. wt, shoot weight, leaf weight, leaf area and leaf number than plants grown without O 3 . LRT plants tended to have slightly smaller total plant d. wt, shoot weight, root weight, leaf weight, leaf area, and leaf number than HRT plants. For all variables, LRT plants grown in O 3 had the smallest biomass, and plants grown in HRT without O 3 had the largest biomass. Ozone reduced both fruit weight and fruit number; LRT also reduced fruit weight but had no effect on fruit number. Ozone reduced photosynthesis but RT had no effect. Conductance and internal CO 2 were unaffected by O 3 or RT. These studies indicate that plant growth with LRT might be more reduced in the presence of O 3 than growth in plants with HRT, which might be able to compensate for O 3 ‐caused reductions in photosynthesis to avoid decreased biomass and reproductive output.