T. Lawson et al., Effects of elevated carbon dioxide and ozone on the growth and yield of potatoes (Solanum tuberosum) grown in open-top chambers, ENVIR POLLU, 111(3), 2001, pp. 479-491
Potato (Solanum tuberosum cv. Bintje) was grown in open-top chambers under
three carbon dioxide (ambient and seasonal mean concentrations of 550 and 6
80 mu mol mol(-1) CO2) and two ozone concentrations (ambient and an 8 h day
(-1) seasonal mean of 50 nmol mol(-1) O-3) between emergence and final harv
est. Periodic non-destructive measurements were made and destructive harves
ts were carried out at three key developmental stages (24, 49 and 101 days
after emergence) to establish effects on growth and tuber yield. Season-lon
g exposure to elevated O-3 reduced above-ground dry weight at final harvest
by 8.4% (P < 0.05), but did not affect tuber yields. There was no signific
ant interaction between CO2 and O-3 for any of the growth and yield variabl
es examined. Non-destructive analyses revealed no significant effect of ele
vated CO2 on plant height, leaf number or green leaf area ratio. However, d
estructive harvests at tuber initiation and 500<degrees>Cd after emergence
showed that above-ground dry weight (8 and 7% respectively) and tuber yield
(88 and 44%) were significantly increased (P < 0.05) in the 550 <mu>mol mo
l(-1) CO2 treatment. Responses to 550 and 680 mu mol mol(-1) CO2 were not s
ignificantly different for most parameters examined, suggesting the existen
ce of an upper limit to the beneficial influence of CO2 enrichment. Signifi
cant effects on above-ground dry weight and tuber yield were no longer appa
rent at final harvest, although tuber numbers were increased (P < 0.05) und
er elevated CO2, particularly in the smaller size categories. The results s
how that the O-3 treatment imposed was insufficient to reduce tuber yields
and that, although elevated CO2 enhanced crop growth during the early stage
s of the season, this beneficial effect was not sustained to maturity. (C)
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