Agriculture Reference
In-Depth Information
Low temperature during fl owering may also cause spikelet
sterility, however its effects are not as pronounced as the ones
caused by cold during pollen formation. Based on data reported
by Alvarado (1999), a decrease in temperature of one degree,
below the threshold air temperature of 20ºC, increases spikelet
sterility by 6%.
After low temperature (16ºC) treatment, the net
photosynthetic rate, chlorophyll content and FBPase activity
tended to decrease and ratio of chlorophyll a/b, stomatal
resistance, sucrose and starch content tended to increase in
rice fl ag leaves at heading stage. However, the Pi content and
water potential did not show pronounced change. The fl ag leaf
chloroplasts contained large starch grains after three days at
low temperature (Jie et al. 1981) (Fig. 28).
Decrease
Net photosynthetic rate
Chlorophyll content
FBPase activity
Low
Increase
Rice plant at
heading
Temperature
Chlorophyll a/b ratio
Stomatal resistance
Sucrose & starch content
Fig. 28
Some physiological changes by cold stress on rice at heading.
