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Arid directly affects crop growth and yield, such as reduces photosynthesis,
weakens respiration rate, slows down the material transport, disorders stomatal
switch, blocks the synthesis of chlorophyll, affects the cell wall and protein
synthesis, etc., eventually leads to the reduction of output. How to solve this
problem? This paper proposes a drought index based on thermal imaging
technology.
Canopy temperature distribution can reflect the growth of crops. And using
thermal imaging technology can access to crop canopy temperature distribution
quickly. Physiological indexes such as the changes of stomatal conductance and
chlorophyll content is the important basis of crop drought resistance
identification.So this paper studied the distribution of wheat canopy
temperature with the change of stomatal conductance and chlorophyll content
under drought conditions.
The study was based on different drought resistant genotypes of winter
wheat in Xinjiang with German JENOPTIK portable infrared thermal imager for
canopy temperature information. The canopy leaf stomatal conductance and
chlorophyll content was measured by SC-1 porosity meter and SPAD chlorophyll
meter. Results prove that winter wheat canopy temperature decreases with the
increase of stomatal conductance in dry conditions, which has a good linear
relationship (r=-0.67). The correlation of canopy temperature and stomatal
conductance of poor drought resistance(-0.93) is greater than that of good
one(-0.46). There is significant difference between stomatal conductance and
chlorophyll content of different drought resistance varieties(P<0.05). The variety
of poor drought resistance is greater that of good one in morning-afternoon
stomatal conductance change. And the chlorophyll content of the variety of good
drought resistance is greater that of poor one.
The conclusions above show that canopy temperature distribution has good
correlation with the crop drought resistance indexes and can be used as an early
indicator of drought resistance identification.This conclusion has important
significance for drought resistance identification, the reasonable irrigation
guidance and improving the water use efficiency.
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