Growth and leaf senescence in spring wheat (Triticum aestivum) grown at different ozone concentrations in open‐top field chambers

Abstract

J. 1989. Growth and leaf senescence in spring: wheat (Triticum aestivum) grown at different ozone concentrations in open-top field chambers. -Physiol. Plant. 77: 389-394.Spring wheat (Triticum aestivum L. cv. Albis) was grown during two consecutive seasons (1987, 1988) in open-top field fumigation chambers at a site in central Switzerland and exposed to different doses of ozone (O3) in order to study O3 effects on growth and leaf senescence. The O3 dose in nonfiltered air (NF) was 42.6 (il I"' h in 1987 and 49.2 [ill"' h in 1988. The other treatments used were: charcoal-filtered air (CF) (0.5 X O3 dose in nonfiltered air) and nonfiltered air with one of two levels of O3 added daily (0900-1700 h) (O3-I with 1.5 x O3 dose in nonfiltered air and O3-2 with L9 X O3 dose in nonfiltered air). From anthesis through senescence, dry weight of individual ears, and chlorophyll and protein content, glutamate dehydrogenase activity (GDH, EC 1.4.1.3), and the content of free and conjugated 1-aminocyclopropane-1-carboxylic acid (ACC and MACC) in flag leaves were determined. With increasing O3 dose, the decline in chlorophyll and soluble protein contents started earlier, but the rate of decline decreased. Independent of the treatment used, GDH activity was highest during the period of maximal protein loss. With increasing O3 dose, the content of MACC increased, while that of free ACC remained unaffected. In 1988, temporal changes in MACC were related to other senescence processes. It is suggested that with increasing stress from chronic O3 exposure leaf duration is reduced, but that the pattern of senescence processes remains unchanged. OEoneinduced acceleration of flag leaf senescence could contribute to the observed reduction in ear dry weight accumulation, which may account for yield reduction in spring wheat.

Effects of ozone on foliar nitrogen metabolism of Pinus taeda L. and implications for carbohydrate metabolism

“…In herbaceous plants, only the activity of GDH and amino acid content increased upon ozone exposure (Grandjean & Fuhrer, 1989;Bender et al, 1991;Manderscheid et al, 1991). The reason for this contrasting response could be due to the differences in leaf life span and growth rate between herbs and conifers.…”

“…At the highest ozone concentration a clear decline in growth rate and pigment concentration was observed and, in one of the three chambers, the trees had lost their second flush of 1989 needles. This process clearly indicated early senescence of the needles, a well-known effect of ozone (Grandjean & Fuhrer, 1989;Adams et al, 19906).…”

“…Ozone is known to accelerate leaf senescence in herbaceous plants (Grandjean & Fuhrer, 1989;Manderscheid et al, 1991) and conifers (Adams et al, 19906;this study). Leaf senescence is a clearly ordered process that is directed towards achieving a high degree of nutrient withdrawal from the leaves and effecting an efficient reallocation of nutrients to the storage sites or the young foliage (Peoples & Dailing, 1988).…”

“…Other aspects, e.g. the consequences of ozone-induced accelerated leaf senescence (Grandjean & Fuhrer, 1989;Adams et al, 19906) for nitrogen metabolism, have scarcely been investigated.…”

Estimating Trends of Mean Monthly Ozone Emission in Urbanised Areas of Malaysia

“…O3 damage to crops has been well related to the reduction in photosynthesis and mis allocation of carbon (Grantz and Yang, 2000); senescence of leaves (Grandjean and Fuhrer, 1989); increased plant infection and injury . Generally, studies of Pleijel et al, 1999;Vorne et al, 2002 have found dicot plants to suffer more yield losses due to ozone exposure than the monocot plants.…”