Effects of water stress on photosynthesis, yield, and water use
efficiency in winter wheat
Drought has become one of the major constraints on agricultural
development, particularly in areas lacking water. Studying the effects
of different water stresses on photosynthesis, growth, yield, water use
efficiency (WUE) and water productivity (IWP) of winter wheat will
provide scientific irrigation strategies for developing water-saving
agriculture. According to the water field capacity, four different water
stress levels were set, i.e., 30–40% of water field capacity (severe
stress), 40–50% (moderate stress), 50–60% (mild stress) and 60–80%
(well-watered), through an automatic irrigation system by controlling
the irrigation amount. The results showed that the diurnal and seasonal
changes in photosynthetic parameters such as net photosynthetic rate
(Pn), intercellular carbon concentration (Ci), stomatal conductance
(Gs), and transpiration (E) significantly decreased under moderate and
severe stress. The Pn of mild stress only slightly decreased compared to
that of well-watered and was even higher after May 16th. As a result,
the dry biomass and 1000-grain weight under mild stress increased 2.07%
and 1.95% compared with well-watered. Under all water stresses, the
heights and straw weights of the winter wheat significantly decreased.
It was also found that mild water stress increased the WUE and IWP,
which further resulted in the negligible decrease of the fresh weight of
the aboveground biomass, dry biomass weight, spike weight, grain weight.
Conversely, WUE and IWP significantly decreased under moderate and
severe stress, which can affect the growth of winter wheat. So the fresh
weight of the aboveground biomass, dry biomass weight, spike weight,
grain weight also significantly decreased under moderate and severe
stress. Thus, mild stress results in the optimal use of water resources
without a significant reduction in yield in the North China Plain.
Therefore, mild stress can be considered as a suitable environment for
winter wheat growth in arid areas.