Agriculture Reference
In-Depth Information
Effect on timing of bud burst, cessation of growth, altered concentra-
tions of carbohydrates and plant hormones in turn altered the dormancy
status of trees thereby changing the timing of bud burst and the length of
the active growing period. Flowering and fruiting of trees are likely to be
hastened under conditions of elevated carbon dioxide. The evidence for
an effect of carbon dioxide concentration on leaf senescence and leaf fall
is rather contradictory and may be species dependent. Most predictions of
the direct effects of carbon dioxide suggested that average yields will in-
crease by about 40-50% with a doubling of carbon dioxide concentrations
Leaves are able to detect and respond rapidly to carbon dioxide concentra-
tion. Stomata opening decreases in response to increased carbon dioxide
concentration.
3.2.13 EFFECTS OF OZONE EXPOSURE FRUIT YIELD AND
QUALITY
Higher concentrations of atmospheric ozone are found during summer
due to increase in nitrogen species and emission of volatile organic com-
pounds (Mauzerall and Wang, 2001). Concentrations are at maximum
values in the late afternoon and at minimum values in the early morning
hours, notably in industrialized cities and vicinities. The opposite phenom-
enon occurs at high latitude sites. Another potential source for increased
levels of ozone in a certain region is via the movement by local winds or
downdrafts from the stratosphere.
3.2.14 EFFECT ON INCIDENCE OF MOSSES AND ALGAE
The increase in temperature, especially if combined with wetter winters,
causes increased incidence of mosses and algae, many of which have low-
er threshold temperatures for growth than those of most flowering plants.
Hotter and drier summers may limit or counter this increase, or at least
result in the mosses and algae adopting their dry resting state for a larger
proportion of the summer.
