Measurement of stem water potential as a sensitive indicator of water stress in neck orange (Citrus reticulata Blanco)

Measurements of stem water potential, leaf water potential and stomatal conductance were simultaneously done in3-year old trees of neck orange. The trees were subjected to 3 levels of watering: 1) daily watering (control), 2) 4-dayinterval watering and 3) 8-day interval watering. It was found that stem water potential was more sensitive to soil moisturethan leaf water potential. This led to high correlation between soil moisture and stem water potential (r2 = 0.80), but the correlation between soil moisture and leaf water potential was low (r2 = 0.66). Likewise, stomatal conductance was highly correlated with stem water potential (r2 = 0.74). The correlation was higher than that of stomatal conductance with leaf water potential (r2 = 0.62).Therefore, stem water potential appears to be a sensitive indicator to assess water stress in neck orange.