Desert winds cam4
Variable wind speed creates unsteady effects on sap flow, due to internal dynamics responses in plants.
For example, it has been discovered that the maximum water uptake rate by the roots lags behind the maximum transpiration rate (Edwards L. They incorporated a time constant parameter into the resistance–capacitance model and estimated the time constant to be ∼48 min for loblolly pine trees.
Their results show that wind increases stomatal resistance in an exponential manner.
Wind speeds (2004) studied the effects of wind speed on photosynthesis of tomato seedlings in a wind tunnel-type chamber.
In the natural world, water transport from the soil into plants and from plants into the atmosphere is largely dependent on five environmental parameters: wind, radiation, temperature, humidity, and soil moisture.
Among them, wind has long been recognized as an important factor influencing plant transpiration.
Under the same wind speed, the steady sap flow rate was smaller than that in the daytime, indicating differences between diurnal and nocturnal hydraulic function, and incomplete stomatal closure at night.
Their results showed that the nocturnal sap flow correlated well with vapour pressure deficit (VPD) and temperature, but the influence of wind speed on night-time transpiration was insignificant.The steady sap flow rate increased as the wind speed increased at low wind speeds.Once the wind speed exceeded 8.0 m s, the steady sap flow rate did not increase further.Dawson (2007) used porometry, stable isotope tracer and heat ratio sap flow sensors to study the night-time transpiration rate of a variety of vegetation types.They found that night-time transpiration rates exceeded 20% of the maximum transpiration rate measured at noon under warm and dry summer conditions; on some occasions night-time transpiration rates exceeding 40% of maximum were observed.
In consequence, the growth of the leaf area was reduced as wind speed increased.